1782 lines
51 KiB
Java
1782 lines
51 KiB
Java
/* TreeMap.java -- a class providing a basic Red-Black Tree data structure,
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mapping Object --> Object
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Copyright (C) 1998, 1999, 2000, 2001, 2002, 2004, 2005 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301 USA.
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Linking this library statically or dynamically with other modules is
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making a combined work based on this library. Thus, the terms and
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conditions of the GNU General Public License cover the whole
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combination.
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As a special exception, the copyright holders of this library give you
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permission to link this library with independent modules to produce an
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executable, regardless of the license terms of these independent
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modules, and to copy and distribute the resulting executable under
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terms of your choice, provided that you also meet, for each linked
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independent module, the terms and conditions of the license of that
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module. An independent module is a module which is not derived from
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or based on this library. If you modify this library, you may extend
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this exception to your version of the library, but you are not
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obligated to do so. If you do not wish to do so, delete this
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exception statement from your version. */
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package java.util;
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import java.io.IOException;
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import java.io.ObjectInputStream;
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import java.io.ObjectOutputStream;
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import java.io.Serializable;
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/**
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* This class provides a red-black tree implementation of the SortedMap
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* interface. Elements in the Map will be sorted by either a user-provided
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* Comparator object, or by the natural ordering of the keys.
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*
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* The algorithms are adopted from Corman, Leiserson, and Rivest's
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* <i>Introduction to Algorithms.</i> TreeMap guarantees O(log n)
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* insertion and deletion of elements. That being said, there is a large
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* enough constant coefficient in front of that "log n" (overhead involved
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* in keeping the tree balanced), that TreeMap may not be the best choice
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* for small collections. If something is already sorted, you may want to
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* just use a LinkedHashMap to maintain the order while providing O(1) access.
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*
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* TreeMap is a part of the JDK1.2 Collections API. Null keys are allowed
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* only if a Comparator is used which can deal with them; natural ordering
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* cannot cope with null. Null values are always allowed. Note that the
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* ordering must be <i>consistent with equals</i> to correctly implement
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* the Map interface. If this condition is violated, the map is still
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* well-behaved, but you may have suprising results when comparing it to
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* other maps.<p>
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*
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* This implementation is not synchronized. If you need to share this between
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* multiple threads, do something like:<br>
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* <code>SortedMap m
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* = Collections.synchronizedSortedMap(new TreeMap(...));</code><p>
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*
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* The iterators are <i>fail-fast</i>, meaning that any structural
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* modification, except for <code>remove()</code> called on the iterator
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* itself, cause the iterator to throw a
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* <code>ConcurrentModificationException</code> rather than exhibit
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* non-deterministic behavior.
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*
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* @author Jon Zeppieri
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* @author Bryce McKinlay
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* @author Eric Blake (ebb9@email.byu.edu)
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* @see Map
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* @see HashMap
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* @see Hashtable
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* @see LinkedHashMap
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* @see Comparable
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* @see Comparator
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* @see Collection
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* @see Collections#synchronizedSortedMap(SortedMap)
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* @since 1.2
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* @status updated to 1.4
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*/
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public class TreeMap extends AbstractMap
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implements SortedMap, Cloneable, Serializable
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{
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// Implementation note:
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// A red-black tree is a binary search tree with the additional properties
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// that all paths to a leaf node visit the same number of black nodes,
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// and no red node has red children. To avoid some null-pointer checks,
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// we use the special node nil which is always black, has no relatives,
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// and has key and value of null (but is not equal to a mapping of null).
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/**
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* Compatible with JDK 1.2.
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*/
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private static final long serialVersionUID = 919286545866124006L;
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/**
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* Color status of a node. Package visible for use by nested classes.
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*/
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static final int RED = -1,
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BLACK = 1;
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/**
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* Sentinal node, used to avoid null checks for corner cases and make the
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* delete rebalance code simpler. The rebalance code must never assign
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* the parent, left, or right of nil, but may safely reassign the color
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* to be black. This object must never be used as a key in a TreeMap, or
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* it will break bounds checking of a SubMap.
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*/
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static final Node nil = new Node(null, null, BLACK);
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static
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{
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// Nil is self-referential, so we must initialize it after creation.
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nil.parent = nil;
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nil.left = nil;
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nil.right = nil;
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}
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/**
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* The root node of this TreeMap.
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*/
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private transient Node root;
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/**
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* The size of this TreeMap. Package visible for use by nested classes.
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*/
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transient int size;
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/**
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* The cache for {@link #entrySet()}.
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*/
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private transient Set entries;
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/**
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* Counts the number of modifications this TreeMap has undergone, used
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* by Iterators to know when to throw ConcurrentModificationExceptions.
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* Package visible for use by nested classes.
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*/
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transient int modCount;
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/**
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* This TreeMap's comparator, or null for natural ordering.
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* Package visible for use by nested classes.
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* @serial the comparator ordering this tree, or null
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*/
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final Comparator comparator;
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/**
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* Class to represent an entry in the tree. Holds a single key-value pair,
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* plus pointers to parent and child nodes.
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*
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* @author Eric Blake (ebb9@email.byu.edu)
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*/
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private static final class Node extends AbstractMap.BasicMapEntry
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{
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// All fields package visible for use by nested classes.
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/** The color of this node. */
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int color;
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/** The left child node. */
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Node left = nil;
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/** The right child node. */
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Node right = nil;
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/** The parent node. */
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Node parent = nil;
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/**
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* Simple constructor.
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* @param key the key
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* @param value the value
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*/
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Node(Object key, Object value, int color)
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{
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super(key, value);
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this.color = color;
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}
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}
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/**
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* Instantiate a new TreeMap with no elements, using the keys' natural
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* ordering to sort. All entries in the map must have a key which implements
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* Comparable, and which are <i>mutually comparable</i>, otherwise map
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* operations may throw a {@link ClassCastException}. Attempts to use
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* a null key will throw a {@link NullPointerException}.
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*
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* @see Comparable
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*/
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public TreeMap()
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{
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this((Comparator) null);
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}
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/**
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* Instantiate a new TreeMap with no elements, using the provided comparator
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* to sort. All entries in the map must have keys which are mutually
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* comparable by the Comparator, otherwise map operations may throw a
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* {@link ClassCastException}.
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*
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* @param comparator the sort order for the keys of this map, or null
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* for the natural order
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*/
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public TreeMap(Comparator c)
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{
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comparator = c;
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fabricateTree(0);
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}
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/**
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* Instantiate a new TreeMap, initializing it with all of the elements in
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* the provided Map. The elements will be sorted using the natural
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* ordering of the keys. This algorithm runs in n*log(n) time. All entries
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* in the map must have keys which implement Comparable and are mutually
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* comparable, otherwise map operations may throw a
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* {@link ClassCastException}.
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*
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* @param map a Map, whose entries will be put into this TreeMap
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* @throws ClassCastException if the keys in the provided Map are not
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* comparable
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* @throws NullPointerException if map is null
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* @see Comparable
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*/
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public TreeMap(Map map)
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{
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this((Comparator) null);
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putAll(map);
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}
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/**
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* Instantiate a new TreeMap, initializing it with all of the elements in
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* the provided SortedMap. The elements will be sorted using the same
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* comparator as in the provided SortedMap. This runs in linear time.
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*
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* @param sm a SortedMap, whose entries will be put into this TreeMap
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* @throws NullPointerException if sm is null
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*/
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public TreeMap(SortedMap sm)
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{
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this(sm.comparator());
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int pos = sm.size();
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Iterator itr = sm.entrySet().iterator();
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fabricateTree(pos);
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Node node = firstNode();
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while (--pos >= 0)
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{
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Map.Entry me = (Map.Entry) itr.next();
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node.key = me.getKey();
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node.value = me.getValue();
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node = successor(node);
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}
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}
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/**
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* Clears the Map so it has no keys. This is O(1).
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*/
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public void clear()
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{
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if (size > 0)
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{
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modCount++;
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root = nil;
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size = 0;
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}
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}
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/**
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* Returns a shallow clone of this TreeMap. The Map itself is cloned,
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* but its contents are not.
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*
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* @return the clone
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*/
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public Object clone()
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{
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TreeMap copy = null;
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try
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{
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copy = (TreeMap) super.clone();
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}
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catch (CloneNotSupportedException x)
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{
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}
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copy.entries = null;
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copy.fabricateTree(size);
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Node node = firstNode();
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Node cnode = copy.firstNode();
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while (node != nil)
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{
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cnode.key = node.key;
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cnode.value = node.value;
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node = successor(node);
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cnode = copy.successor(cnode);
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}
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return copy;
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}
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/**
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* Return the comparator used to sort this map, or null if it is by
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* natural order.
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*
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* @return the map's comparator
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*/
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public Comparator comparator()
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{
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return comparator;
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}
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/**
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* Returns true if the map contains a mapping for the given key.
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*
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* @param key the key to look for
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* @return true if the key has a mapping
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* @throws ClassCastException if key is not comparable to map elements
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* @throws NullPointerException if key is null and the comparator is not
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* tolerant of nulls
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*/
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public boolean containsKey(Object key)
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{
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return getNode(key) != nil;
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}
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/**
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* Returns true if the map contains at least one mapping to the given value.
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* This requires linear time.
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*
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* @param value the value to look for
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* @return true if the value appears in a mapping
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*/
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public boolean containsValue(Object value)
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{
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Node node = firstNode();
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while (node != nil)
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{
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if (equals(value, node.value))
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return true;
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node = successor(node);
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}
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return false;
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}
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/**
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* Returns a "set view" of this TreeMap's entries. The set is backed by
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* the TreeMap, so changes in one show up in the other. The set supports
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* element removal, but not element addition.<p>
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*
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* Note that the iterators for all three views, from keySet(), entrySet(),
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* and values(), traverse the TreeMap in sorted sequence.
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*
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* @return a set view of the entries
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* @see #keySet()
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* @see #values()
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* @see Map.Entry
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*/
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public Set entrySet()
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{
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if (entries == null)
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// Create an AbstractSet with custom implementations of those methods
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// that can be overriden easily and efficiently.
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entries = new AbstractSet()
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{
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public int size()
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{
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return size;
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}
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public Iterator iterator()
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{
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return new TreeIterator(ENTRIES);
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}
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public void clear()
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{
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TreeMap.this.clear();
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}
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public boolean contains(Object o)
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{
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if (! (o instanceof Map.Entry))
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return false;
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Map.Entry me = (Map.Entry) o;
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Node n = getNode(me.getKey());
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return n != nil && AbstractSet.equals(me.getValue(), n.value);
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}
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public boolean remove(Object o)
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{
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if (! (o instanceof Map.Entry))
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return false;
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Map.Entry me = (Map.Entry) o;
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Node n = getNode(me.getKey());
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if (n != nil && AbstractSet.equals(me.getValue(), n.value))
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{
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removeNode(n);
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return true;
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}
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return false;
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}
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};
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return entries;
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}
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/**
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* Returns the first (lowest) key in the map.
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*
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* @return the first key
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* @throws NoSuchElementException if the map is empty
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*/
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public Object firstKey()
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{
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if (root == nil)
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throw new NoSuchElementException();
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return firstNode().key;
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}
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/**
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* Return the value in this TreeMap associated with the supplied key,
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* or <code>null</code> if the key maps to nothing. NOTE: Since the value
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* could also be null, you must use containsKey to see if this key
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* actually maps to something.
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*
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* @param key the key for which to fetch an associated value
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* @return what the key maps to, if present
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* @throws ClassCastException if key is not comparable to elements in the map
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* @throws NullPointerException if key is null but the comparator does not
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* tolerate nulls
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* @see #put(Object, Object)
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* @see #containsKey(Object)
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*/
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public Object get(Object key)
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{
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// Exploit fact that nil.value == null.
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return getNode(key).value;
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}
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/**
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* Returns a view of this Map including all entries with keys less than
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* <code>toKey</code>. The returned map is backed by the original, so changes
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* in one appear in the other. The submap will throw an
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* {@link IllegalArgumentException} for any attempt to access or add an
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* element beyond the specified cutoff. The returned map does not include
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* the endpoint; if you want inclusion, pass the successor element.
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*
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* @param toKey the (exclusive) cutoff point
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* @return a view of the map less than the cutoff
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* @throws ClassCastException if <code>toKey</code> is not compatible with
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* the comparator (or is not Comparable, for natural ordering)
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* @throws NullPointerException if toKey is null, but the comparator does not
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* tolerate null elements
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*/
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public SortedMap headMap(Object toKey)
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{
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return new SubMap(nil, toKey);
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}
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/**
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* Returns a "set view" of this TreeMap's keys. The set is backed by the
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* TreeMap, so changes in one show up in the other. The set supports
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* element removal, but not element addition.
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*
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* @return a set view of the keys
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* @see #values()
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* @see #entrySet()
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*/
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public Set keySet()
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{
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if (keys == null)
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// Create an AbstractSet with custom implementations of those methods
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// that can be overriden easily and efficiently.
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keys = new AbstractSet()
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{
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public int size()
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{
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return size;
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}
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public Iterator iterator()
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{
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return new TreeIterator(KEYS);
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}
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public void clear()
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{
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TreeMap.this.clear();
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}
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public boolean contains(Object o)
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{
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return containsKey(o);
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}
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public boolean remove(Object key)
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{
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Node n = getNode(key);
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if (n == nil)
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return false;
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removeNode(n);
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return true;
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}
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};
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return keys;
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}
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/**
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* Returns the last (highest) key in the map.
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*
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* @return the last key
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* @throws NoSuchElementException if the map is empty
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*/
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public Object lastKey()
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{
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if (root == nil)
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throw new NoSuchElementException("empty");
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return lastNode().key;
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}
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/**
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* Puts the supplied value into the Map, mapped by the supplied key.
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* The value may be retrieved by any object which <code>equals()</code>
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* this key. NOTE: Since the prior value could also be null, you must
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* first use containsKey if you want to see if you are replacing the
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* key's mapping.
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*
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* @param key the key used to locate the value
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* @param value the value to be stored in the Map
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* @return the prior mapping of the key, or null if there was none
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* @throws ClassCastException if key is not comparable to current map keys
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* @throws NullPointerException if key is null, but the comparator does
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* not tolerate nulls
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* @see #get(Object)
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* @see Object#equals(Object)
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*/
|
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public Object put(Object key, Object value)
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{
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Node current = root;
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Node parent = nil;
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int comparison = 0;
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// Find new node's parent.
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while (current != nil)
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{
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parent = current;
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comparison = compare(key, current.key);
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if (comparison > 0)
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current = current.right;
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else if (comparison < 0)
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current = current.left;
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else // Key already in tree.
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return current.setValue(value);
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}
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// Set up new node.
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Node n = new Node(key, value, RED);
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n.parent = parent;
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|
|
|
// Insert node in tree.
|
|
modCount++;
|
|
size++;
|
|
if (parent == nil)
|
|
{
|
|
// Special case inserting into an empty tree.
|
|
root = n;
|
|
return null;
|
|
}
|
|
if (comparison > 0)
|
|
parent.right = n;
|
|
else
|
|
parent.left = n;
|
|
|
|
// Rebalance after insert.
|
|
insertFixup(n);
|
|
return null;
|
|
}
|
|
|
|
/**
|
|
* Copies all elements of the given map into this TreeMap. If this map
|
|
* already has a mapping for a key, the new mapping replaces the current
|
|
* one.
|
|
*
|
|
* @param m the map to be added
|
|
* @throws ClassCastException if a key in m is not comparable with keys
|
|
* in the map
|
|
* @throws NullPointerException if a key in m is null, and the comparator
|
|
* does not tolerate nulls
|
|
*/
|
|
public void putAll(Map m)
|
|
{
|
|
Iterator itr = m.entrySet().iterator();
|
|
int pos = m.size();
|
|
while (--pos >= 0)
|
|
{
|
|
Map.Entry e = (Map.Entry) itr.next();
|
|
put(e.getKey(), e.getValue());
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Removes from the TreeMap and returns the value which is mapped by the
|
|
* supplied key. If the key maps to nothing, then the TreeMap remains
|
|
* unchanged, and <code>null</code> is returned. NOTE: Since the value
|
|
* could also be null, you must use containsKey to see if you are
|
|
* actually removing a mapping.
|
|
*
|
|
* @param key the key used to locate the value to remove
|
|
* @return whatever the key mapped to, if present
|
|
* @throws ClassCastException if key is not comparable to current map keys
|
|
* @throws NullPointerException if key is null, but the comparator does
|
|
* not tolerate nulls
|
|
*/
|
|
public Object remove(Object key)
|
|
{
|
|
Node n = getNode(key);
|
|
if (n == nil)
|
|
return null;
|
|
// Note: removeNode can alter the contents of n, so save value now.
|
|
Object result = n.value;
|
|
removeNode(n);
|
|
return result;
|
|
}
|
|
|
|
/**
|
|
* Returns the number of key-value mappings currently in this Map.
|
|
*
|
|
* @return the size
|
|
*/
|
|
public int size()
|
|
{
|
|
return size;
|
|
}
|
|
|
|
/**
|
|
* Returns a view of this Map including all entries with keys greater or
|
|
* equal to <code>fromKey</code> and less than <code>toKey</code> (a
|
|
* half-open interval). The returned map is backed by the original, so
|
|
* changes in one appear in the other. The submap will throw an
|
|
* {@link IllegalArgumentException} for any attempt to access or add an
|
|
* element beyond the specified cutoffs. The returned map includes the low
|
|
* endpoint but not the high; if you want to reverse this behavior on
|
|
* either end, pass in the successor element.
|
|
*
|
|
* @param fromKey the (inclusive) low cutoff point
|
|
* @param toKey the (exclusive) high cutoff point
|
|
* @return a view of the map between the cutoffs
|
|
* @throws ClassCastException if either cutoff is not compatible with
|
|
* the comparator (or is not Comparable, for natural ordering)
|
|
* @throws NullPointerException if fromKey or toKey is null, but the
|
|
* comparator does not tolerate null elements
|
|
* @throws IllegalArgumentException if fromKey is greater than toKey
|
|
*/
|
|
public SortedMap subMap(Object fromKey, Object toKey)
|
|
{
|
|
return new SubMap(fromKey, toKey);
|
|
}
|
|
|
|
/**
|
|
* Returns a view of this Map including all entries with keys greater or
|
|
* equal to <code>fromKey</code>. The returned map is backed by the
|
|
* original, so changes in one appear in the other. The submap will throw an
|
|
* {@link IllegalArgumentException} for any attempt to access or add an
|
|
* element beyond the specified cutoff. The returned map includes the
|
|
* endpoint; if you want to exclude it, pass in the successor element.
|
|
*
|
|
* @param fromKey the (inclusive) low cutoff point
|
|
* @return a view of the map above the cutoff
|
|
* @throws ClassCastException if <code>fromKey</code> is not compatible with
|
|
* the comparator (or is not Comparable, for natural ordering)
|
|
* @throws NullPointerException if fromKey is null, but the comparator
|
|
* does not tolerate null elements
|
|
*/
|
|
public SortedMap tailMap(Object fromKey)
|
|
{
|
|
return new SubMap(fromKey, nil);
|
|
}
|
|
|
|
/**
|
|
* Returns a "collection view" (or "bag view") of this TreeMap's values.
|
|
* The collection is backed by the TreeMap, so changes in one show up
|
|
* in the other. The collection supports element removal, but not element
|
|
* addition.
|
|
*
|
|
* @return a bag view of the values
|
|
* @see #keySet()
|
|
* @see #entrySet()
|
|
*/
|
|
public Collection values()
|
|
{
|
|
if (values == null)
|
|
// We don't bother overriding many of the optional methods, as doing so
|
|
// wouldn't provide any significant performance advantage.
|
|
values = new AbstractCollection()
|
|
{
|
|
public int size()
|
|
{
|
|
return size;
|
|
}
|
|
|
|
public Iterator iterator()
|
|
{
|
|
return new TreeIterator(VALUES);
|
|
}
|
|
|
|
public void clear()
|
|
{
|
|
TreeMap.this.clear();
|
|
}
|
|
};
|
|
return values;
|
|
}
|
|
|
|
/**
|
|
* Compares two elements by the set comparator, or by natural ordering.
|
|
* Package visible for use by nested classes.
|
|
*
|
|
* @param o1 the first object
|
|
* @param o2 the second object
|
|
* @throws ClassCastException if o1 and o2 are not mutually comparable,
|
|
* or are not Comparable with natural ordering
|
|
* @throws NullPointerException if o1 or o2 is null with natural ordering
|
|
*/
|
|
final int compare(Object o1, Object o2)
|
|
{
|
|
return (comparator == null
|
|
? ((Comparable) o1).compareTo(o2)
|
|
: comparator.compare(o1, o2));
|
|
}
|
|
|
|
/**
|
|
* Maintain red-black balance after deleting a node.
|
|
*
|
|
* @param node the child of the node just deleted, possibly nil
|
|
* @param parent the parent of the node just deleted, never nil
|
|
*/
|
|
private void deleteFixup(Node node, Node parent)
|
|
{
|
|
// if (parent == nil)
|
|
// throw new InternalError();
|
|
// If a black node has been removed, we need to rebalance to avoid
|
|
// violating the "same number of black nodes on any path" rule. If
|
|
// node is red, we can simply recolor it black and all is well.
|
|
while (node != root && node.color == BLACK)
|
|
{
|
|
if (node == parent.left)
|
|
{
|
|
// Rebalance left side.
|
|
Node sibling = parent.right;
|
|
// if (sibling == nil)
|
|
// throw new InternalError();
|
|
if (sibling.color == RED)
|
|
{
|
|
// Case 1: Sibling is red.
|
|
// Recolor sibling and parent, and rotate parent left.
|
|
sibling.color = BLACK;
|
|
parent.color = RED;
|
|
rotateLeft(parent);
|
|
sibling = parent.right;
|
|
}
|
|
|
|
if (sibling.left.color == BLACK && sibling.right.color == BLACK)
|
|
{
|
|
// Case 2: Sibling has no red children.
|
|
// Recolor sibling, and move to parent.
|
|
sibling.color = RED;
|
|
node = parent;
|
|
parent = parent.parent;
|
|
}
|
|
else
|
|
{
|
|
if (sibling.right.color == BLACK)
|
|
{
|
|
// Case 3: Sibling has red left child.
|
|
// Recolor sibling and left child, rotate sibling right.
|
|
sibling.left.color = BLACK;
|
|
sibling.color = RED;
|
|
rotateRight(sibling);
|
|
sibling = parent.right;
|
|
}
|
|
// Case 4: Sibling has red right child. Recolor sibling,
|
|
// right child, and parent, and rotate parent left.
|
|
sibling.color = parent.color;
|
|
parent.color = BLACK;
|
|
sibling.right.color = BLACK;
|
|
rotateLeft(parent);
|
|
node = root; // Finished.
|
|
}
|
|
}
|
|
else
|
|
{
|
|
// Symmetric "mirror" of left-side case.
|
|
Node sibling = parent.left;
|
|
// if (sibling == nil)
|
|
// throw new InternalError();
|
|
if (sibling.color == RED)
|
|
{
|
|
// Case 1: Sibling is red.
|
|
// Recolor sibling and parent, and rotate parent right.
|
|
sibling.color = BLACK;
|
|
parent.color = RED;
|
|
rotateRight(parent);
|
|
sibling = parent.left;
|
|
}
|
|
|
|
if (sibling.right.color == BLACK && sibling.left.color == BLACK)
|
|
{
|
|
// Case 2: Sibling has no red children.
|
|
// Recolor sibling, and move to parent.
|
|
sibling.color = RED;
|
|
node = parent;
|
|
parent = parent.parent;
|
|
}
|
|
else
|
|
{
|
|
if (sibling.left.color == BLACK)
|
|
{
|
|
// Case 3: Sibling has red right child.
|
|
// Recolor sibling and right child, rotate sibling left.
|
|
sibling.right.color = BLACK;
|
|
sibling.color = RED;
|
|
rotateLeft(sibling);
|
|
sibling = parent.left;
|
|
}
|
|
// Case 4: Sibling has red left child. Recolor sibling,
|
|
// left child, and parent, and rotate parent right.
|
|
sibling.color = parent.color;
|
|
parent.color = BLACK;
|
|
sibling.left.color = BLACK;
|
|
rotateRight(parent);
|
|
node = root; // Finished.
|
|
}
|
|
}
|
|
}
|
|
node.color = BLACK;
|
|
}
|
|
|
|
/**
|
|
* Construct a perfectly balanced tree consisting of n "blank" nodes. This
|
|
* permits a tree to be generated from pre-sorted input in linear time.
|
|
*
|
|
* @param count the number of blank nodes, non-negative
|
|
*/
|
|
private void fabricateTree(final int count)
|
|
{
|
|
if (count == 0)
|
|
{
|
|
root = nil;
|
|
size = 0;
|
|
return;
|
|
}
|
|
|
|
// We color every row of nodes black, except for the overflow nodes.
|
|
// I believe that this is the optimal arrangement. We construct the tree
|
|
// in place by temporarily linking each node to the next node in the row,
|
|
// then updating those links to the children when working on the next row.
|
|
|
|
// Make the root node.
|
|
root = new Node(null, null, BLACK);
|
|
size = count;
|
|
Node row = root;
|
|
int rowsize;
|
|
|
|
// Fill each row that is completely full of nodes.
|
|
for (rowsize = 2; rowsize + rowsize <= count; rowsize <<= 1)
|
|
{
|
|
Node parent = row;
|
|
Node last = null;
|
|
for (int i = 0; i < rowsize; i += 2)
|
|
{
|
|
Node left = new Node(null, null, BLACK);
|
|
Node right = new Node(null, null, BLACK);
|
|
left.parent = parent;
|
|
left.right = right;
|
|
right.parent = parent;
|
|
parent.left = left;
|
|
Node next = parent.right;
|
|
parent.right = right;
|
|
parent = next;
|
|
if (last != null)
|
|
last.right = left;
|
|
last = right;
|
|
}
|
|
row = row.left;
|
|
}
|
|
|
|
// Now do the partial final row in red.
|
|
int overflow = count - rowsize;
|
|
Node parent = row;
|
|
int i;
|
|
for (i = 0; i < overflow; i += 2)
|
|
{
|
|
Node left = new Node(null, null, RED);
|
|
Node right = new Node(null, null, RED);
|
|
left.parent = parent;
|
|
right.parent = parent;
|
|
parent.left = left;
|
|
Node next = parent.right;
|
|
parent.right = right;
|
|
parent = next;
|
|
}
|
|
// Add a lone left node if necessary.
|
|
if (i - overflow == 0)
|
|
{
|
|
Node left = new Node(null, null, RED);
|
|
left.parent = parent;
|
|
parent.left = left;
|
|
parent = parent.right;
|
|
left.parent.right = nil;
|
|
}
|
|
// Unlink the remaining nodes of the previous row.
|
|
while (parent != nil)
|
|
{
|
|
Node next = parent.right;
|
|
parent.right = nil;
|
|
parent = next;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Returns the first sorted node in the map, or nil if empty. Package
|
|
* visible for use by nested classes.
|
|
*
|
|
* @return the first node
|
|
*/
|
|
final Node firstNode()
|
|
{
|
|
// Exploit fact that nil.left == nil.
|
|
Node node = root;
|
|
while (node.left != nil)
|
|
node = node.left;
|
|
return node;
|
|
}
|
|
|
|
/**
|
|
* Return the TreeMap.Node associated with key, or the nil node if no such
|
|
* node exists in the tree. Package visible for use by nested classes.
|
|
*
|
|
* @param key the key to search for
|
|
* @return the node where the key is found, or nil
|
|
*/
|
|
final Node getNode(Object key)
|
|
{
|
|
Node current = root;
|
|
while (current != nil)
|
|
{
|
|
int comparison = compare(key, current.key);
|
|
if (comparison > 0)
|
|
current = current.right;
|
|
else if (comparison < 0)
|
|
current = current.left;
|
|
else
|
|
return current;
|
|
}
|
|
return current;
|
|
}
|
|
|
|
/**
|
|
* Find the "highest" node which is < key. If key is nil, return last
|
|
* node. Package visible for use by nested classes.
|
|
*
|
|
* @param key the upper bound, exclusive
|
|
* @return the previous node
|
|
*/
|
|
final Node highestLessThan(Object key)
|
|
{
|
|
if (key == nil)
|
|
return lastNode();
|
|
|
|
Node last = nil;
|
|
Node current = root;
|
|
int comparison = 0;
|
|
|
|
while (current != nil)
|
|
{
|
|
last = current;
|
|
comparison = compare(key, current.key);
|
|
if (comparison > 0)
|
|
current = current.right;
|
|
else if (comparison < 0)
|
|
current = current.left;
|
|
else // Exact match.
|
|
return predecessor(last);
|
|
}
|
|
return comparison <= 0 ? predecessor(last) : last;
|
|
}
|
|
|
|
/**
|
|
* Maintain red-black balance after inserting a new node.
|
|
*
|
|
* @param n the newly inserted node
|
|
*/
|
|
private void insertFixup(Node n)
|
|
{
|
|
// Only need to rebalance when parent is a RED node, and while at least
|
|
// 2 levels deep into the tree (ie: node has a grandparent). Remember
|
|
// that nil.color == BLACK.
|
|
while (n.parent.color == RED && n.parent.parent != nil)
|
|
{
|
|
if (n.parent == n.parent.parent.left)
|
|
{
|
|
Node uncle = n.parent.parent.right;
|
|
// Uncle may be nil, in which case it is BLACK.
|
|
if (uncle.color == RED)
|
|
{
|
|
// Case 1. Uncle is RED: Change colors of parent, uncle,
|
|
// and grandparent, and move n to grandparent.
|
|
n.parent.color = BLACK;
|
|
uncle.color = BLACK;
|
|
uncle.parent.color = RED;
|
|
n = uncle.parent;
|
|
}
|
|
else
|
|
{
|
|
if (n == n.parent.right)
|
|
{
|
|
// Case 2. Uncle is BLACK and x is right child.
|
|
// Move n to parent, and rotate n left.
|
|
n = n.parent;
|
|
rotateLeft(n);
|
|
}
|
|
// Case 3. Uncle is BLACK and x is left child.
|
|
// Recolor parent, grandparent, and rotate grandparent right.
|
|
n.parent.color = BLACK;
|
|
n.parent.parent.color = RED;
|
|
rotateRight(n.parent.parent);
|
|
}
|
|
}
|
|
else
|
|
{
|
|
// Mirror image of above code.
|
|
Node uncle = n.parent.parent.left;
|
|
// Uncle may be nil, in which case it is BLACK.
|
|
if (uncle.color == RED)
|
|
{
|
|
// Case 1. Uncle is RED: Change colors of parent, uncle,
|
|
// and grandparent, and move n to grandparent.
|
|
n.parent.color = BLACK;
|
|
uncle.color = BLACK;
|
|
uncle.parent.color = RED;
|
|
n = uncle.parent;
|
|
}
|
|
else
|
|
{
|
|
if (n == n.parent.left)
|
|
{
|
|
// Case 2. Uncle is BLACK and x is left child.
|
|
// Move n to parent, and rotate n right.
|
|
n = n.parent;
|
|
rotateRight(n);
|
|
}
|
|
// Case 3. Uncle is BLACK and x is right child.
|
|
// Recolor parent, grandparent, and rotate grandparent left.
|
|
n.parent.color = BLACK;
|
|
n.parent.parent.color = RED;
|
|
rotateLeft(n.parent.parent);
|
|
}
|
|
}
|
|
}
|
|
root.color = BLACK;
|
|
}
|
|
|
|
/**
|
|
* Returns the last sorted node in the map, or nil if empty.
|
|
*
|
|
* @return the last node
|
|
*/
|
|
private Node lastNode()
|
|
{
|
|
// Exploit fact that nil.right == nil.
|
|
Node node = root;
|
|
while (node.right != nil)
|
|
node = node.right;
|
|
return node;
|
|
}
|
|
|
|
/**
|
|
* Find the "lowest" node which is >= key. If key is nil, return either
|
|
* nil or the first node, depending on the parameter first.
|
|
* Package visible for use by nested classes.
|
|
*
|
|
* @param key the lower bound, inclusive
|
|
* @param first true to return the first element instead of nil for nil key
|
|
* @return the next node
|
|
*/
|
|
final Node lowestGreaterThan(Object key, boolean first)
|
|
{
|
|
if (key == nil)
|
|
return first ? firstNode() : nil;
|
|
|
|
Node last = nil;
|
|
Node current = root;
|
|
int comparison = 0;
|
|
|
|
while (current != nil)
|
|
{
|
|
last = current;
|
|
comparison = compare(key, current.key);
|
|
if (comparison > 0)
|
|
current = current.right;
|
|
else if (comparison < 0)
|
|
current = current.left;
|
|
else
|
|
return current;
|
|
}
|
|
return comparison > 0 ? successor(last) : last;
|
|
}
|
|
|
|
/**
|
|
* Return the node preceding the given one, or nil if there isn't one.
|
|
*
|
|
* @param node the current node, not nil
|
|
* @return the prior node in sorted order
|
|
*/
|
|
private Node predecessor(Node node)
|
|
{
|
|
if (node.left != nil)
|
|
{
|
|
node = node.left;
|
|
while (node.right != nil)
|
|
node = node.right;
|
|
return node;
|
|
}
|
|
|
|
Node parent = node.parent;
|
|
// Exploit fact that nil.left == nil and node is non-nil.
|
|
while (node == parent.left)
|
|
{
|
|
node = parent;
|
|
parent = node.parent;
|
|
}
|
|
return parent;
|
|
}
|
|
|
|
/**
|
|
* Construct a tree from sorted keys in linear time. Package visible for
|
|
* use by TreeSet.
|
|
*
|
|
* @param s the stream to read from
|
|
* @param count the number of keys to read
|
|
* @param readValue true to read values, false to insert "" as the value
|
|
* @throws ClassNotFoundException if the underlying stream fails
|
|
* @throws IOException if the underlying stream fails
|
|
* @see #readObject(ObjectInputStream)
|
|
* @see TreeSet#readObject(ObjectInputStream)
|
|
*/
|
|
final void putFromObjStream(ObjectInputStream s, int count,
|
|
boolean readValues)
|
|
throws IOException, ClassNotFoundException
|
|
{
|
|
fabricateTree(count);
|
|
Node node = firstNode();
|
|
|
|
while (--count >= 0)
|
|
{
|
|
node.key = s.readObject();
|
|
node.value = readValues ? s.readObject() : "";
|
|
node = successor(node);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Construct a tree from sorted keys in linear time, with values of "".
|
|
* Package visible for use by TreeSet.
|
|
*
|
|
* @param keys the iterator over the sorted keys
|
|
* @param count the number of nodes to insert
|
|
* @see TreeSet#TreeSet(SortedSet)
|
|
*/
|
|
final void putKeysLinear(Iterator keys, int count)
|
|
{
|
|
fabricateTree(count);
|
|
Node node = firstNode();
|
|
|
|
while (--count >= 0)
|
|
{
|
|
node.key = keys.next();
|
|
node.value = "";
|
|
node = successor(node);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Deserializes this object from the given stream.
|
|
*
|
|
* @param s the stream to read from
|
|
* @throws ClassNotFoundException if the underlying stream fails
|
|
* @throws IOException if the underlying stream fails
|
|
* @serialData the <i>size</i> (int), followed by key (Object) and value
|
|
* (Object) pairs in sorted order
|
|
*/
|
|
private void readObject(ObjectInputStream s)
|
|
throws IOException, ClassNotFoundException
|
|
{
|
|
s.defaultReadObject();
|
|
int size = s.readInt();
|
|
putFromObjStream(s, size, true);
|
|
}
|
|
|
|
/**
|
|
* Remove node from tree. This will increment modCount and decrement size.
|
|
* Node must exist in the tree. Package visible for use by nested classes.
|
|
*
|
|
* @param node the node to remove
|
|
*/
|
|
final void removeNode(Node node)
|
|
{
|
|
Node splice;
|
|
Node child;
|
|
|
|
modCount++;
|
|
size--;
|
|
|
|
// Find splice, the node at the position to actually remove from the tree.
|
|
if (node.left == nil)
|
|
{
|
|
// Node to be deleted has 0 or 1 children.
|
|
splice = node;
|
|
child = node.right;
|
|
}
|
|
else if (node.right == nil)
|
|
{
|
|
// Node to be deleted has 1 child.
|
|
splice = node;
|
|
child = node.left;
|
|
}
|
|
else
|
|
{
|
|
// Node has 2 children. Splice is node's predecessor, and we swap
|
|
// its contents into node.
|
|
splice = node.left;
|
|
while (splice.right != nil)
|
|
splice = splice.right;
|
|
child = splice.left;
|
|
node.key = splice.key;
|
|
node.value = splice.value;
|
|
}
|
|
|
|
// Unlink splice from the tree.
|
|
Node parent = splice.parent;
|
|
if (child != nil)
|
|
child.parent = parent;
|
|
if (parent == nil)
|
|
{
|
|
// Special case for 0 or 1 node remaining.
|
|
root = child;
|
|
return;
|
|
}
|
|
if (splice == parent.left)
|
|
parent.left = child;
|
|
else
|
|
parent.right = child;
|
|
|
|
if (splice.color == BLACK)
|
|
deleteFixup(child, parent);
|
|
}
|
|
|
|
/**
|
|
* Rotate node n to the left.
|
|
*
|
|
* @param node the node to rotate
|
|
*/
|
|
private void rotateLeft(Node node)
|
|
{
|
|
Node child = node.right;
|
|
// if (node == nil || child == nil)
|
|
// throw new InternalError();
|
|
|
|
// Establish node.right link.
|
|
node.right = child.left;
|
|
if (child.left != nil)
|
|
child.left.parent = node;
|
|
|
|
// Establish child->parent link.
|
|
child.parent = node.parent;
|
|
if (node.parent != nil)
|
|
{
|
|
if (node == node.parent.left)
|
|
node.parent.left = child;
|
|
else
|
|
node.parent.right = child;
|
|
}
|
|
else
|
|
root = child;
|
|
|
|
// Link n and child.
|
|
child.left = node;
|
|
node.parent = child;
|
|
}
|
|
|
|
/**
|
|
* Rotate node n to the right.
|
|
*
|
|
* @param node the node to rotate
|
|
*/
|
|
private void rotateRight(Node node)
|
|
{
|
|
Node child = node.left;
|
|
// if (node == nil || child == nil)
|
|
// throw new InternalError();
|
|
|
|
// Establish node.left link.
|
|
node.left = child.right;
|
|
if (child.right != nil)
|
|
child.right.parent = node;
|
|
|
|
// Establish child->parent link.
|
|
child.parent = node.parent;
|
|
if (node.parent != nil)
|
|
{
|
|
if (node == node.parent.right)
|
|
node.parent.right = child;
|
|
else
|
|
node.parent.left = child;
|
|
}
|
|
else
|
|
root = child;
|
|
|
|
// Link n and child.
|
|
child.right = node;
|
|
node.parent = child;
|
|
}
|
|
|
|
/**
|
|
* Return the node following the given one, or nil if there isn't one.
|
|
* Package visible for use by nested classes.
|
|
*
|
|
* @param node the current node, not nil
|
|
* @return the next node in sorted order
|
|
*/
|
|
final Node successor(Node node)
|
|
{
|
|
if (node.right != nil)
|
|
{
|
|
node = node.right;
|
|
while (node.left != nil)
|
|
node = node.left;
|
|
return node;
|
|
}
|
|
|
|
Node parent = node.parent;
|
|
// Exploit fact that nil.right == nil and node is non-nil.
|
|
while (node == parent.right)
|
|
{
|
|
node = parent;
|
|
parent = parent.parent;
|
|
}
|
|
return parent;
|
|
}
|
|
|
|
/**
|
|
* Serializes this object to the given stream.
|
|
*
|
|
* @param s the stream to write to
|
|
* @throws IOException if the underlying stream fails
|
|
* @serialData the <i>size</i> (int), followed by key (Object) and value
|
|
* (Object) pairs in sorted order
|
|
*/
|
|
private void writeObject(ObjectOutputStream s) throws IOException
|
|
{
|
|
s.defaultWriteObject();
|
|
|
|
Node node = firstNode();
|
|
s.writeInt(size);
|
|
while (node != nil)
|
|
{
|
|
s.writeObject(node.key);
|
|
s.writeObject(node.value);
|
|
node = successor(node);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Iterate over TreeMap's entries. This implementation is parameterized
|
|
* to give a sequential view of keys, values, or entries.
|
|
*
|
|
* @author Eric Blake (ebb9@email.byu.edu)
|
|
*/
|
|
private final class TreeIterator implements Iterator
|
|
{
|
|
/**
|
|
* The type of this Iterator: {@link #KEYS}, {@link #VALUES},
|
|
* or {@link #ENTRIES}.
|
|
*/
|
|
private final int type;
|
|
/** The number of modifications to the backing Map that we know about. */
|
|
private int knownMod = modCount;
|
|
/** The last Entry returned by a next() call. */
|
|
private Node last;
|
|
/** The next entry that should be returned by next(). */
|
|
private Node next;
|
|
/**
|
|
* The last node visible to this iterator. This is used when iterating
|
|
* on a SubMap.
|
|
*/
|
|
private final Node max;
|
|
|
|
/**
|
|
* Construct a new TreeIterator with the supplied type.
|
|
* @param type {@link #KEYS}, {@link #VALUES}, or {@link #ENTRIES}
|
|
*/
|
|
TreeIterator(int type)
|
|
{
|
|
// FIXME gcj cannot handle this. Bug java/4695
|
|
// this(type, firstNode(), nil);
|
|
this.type = type;
|
|
this.next = firstNode();
|
|
this.max = nil;
|
|
}
|
|
|
|
/**
|
|
* Construct a new TreeIterator with the supplied type. Iteration will
|
|
* be from "first" (inclusive) to "max" (exclusive).
|
|
*
|
|
* @param type {@link #KEYS}, {@link #VALUES}, or {@link #ENTRIES}
|
|
* @param first where to start iteration, nil for empty iterator
|
|
* @param max the cutoff for iteration, nil for all remaining nodes
|
|
*/
|
|
TreeIterator(int type, Node first, Node max)
|
|
{
|
|
this.type = type;
|
|
this.next = first;
|
|
this.max = max;
|
|
}
|
|
|
|
/**
|
|
* Returns true if the Iterator has more elements.
|
|
* @return true if there are more elements
|
|
* @throws ConcurrentModificationException if the TreeMap was modified
|
|
*/
|
|
public boolean hasNext()
|
|
{
|
|
if (knownMod != modCount)
|
|
throw new ConcurrentModificationException();
|
|
return next != max;
|
|
}
|
|
|
|
/**
|
|
* Returns the next element in the Iterator's sequential view.
|
|
* @return the next element
|
|
* @throws ConcurrentModificationException if the TreeMap was modified
|
|
* @throws NoSuchElementException if there is none
|
|
*/
|
|
public Object next()
|
|
{
|
|
if (knownMod != modCount)
|
|
throw new ConcurrentModificationException();
|
|
if (next == max)
|
|
throw new NoSuchElementException();
|
|
last = next;
|
|
next = successor(last);
|
|
|
|
if (type == VALUES)
|
|
return last.value;
|
|
else if (type == KEYS)
|
|
return last.key;
|
|
return last;
|
|
}
|
|
|
|
/**
|
|
* Removes from the backing TreeMap the last element which was fetched
|
|
* with the <code>next()</code> method.
|
|
* @throws ConcurrentModificationException if the TreeMap was modified
|
|
* @throws IllegalStateException if called when there is no last element
|
|
*/
|
|
public void remove()
|
|
{
|
|
if (last == null)
|
|
throw new IllegalStateException();
|
|
if (knownMod != modCount)
|
|
throw new ConcurrentModificationException();
|
|
|
|
removeNode(last);
|
|
last = null;
|
|
knownMod++;
|
|
}
|
|
} // class TreeIterator
|
|
|
|
/**
|
|
* Implementation of {@link #subMap(Object, Object)} and other map
|
|
* ranges. This class provides a view of a portion of the original backing
|
|
* map, and throws {@link IllegalArgumentException} for attempts to
|
|
* access beyond that range.
|
|
*
|
|
* @author Eric Blake (ebb9@email.byu.edu)
|
|
*/
|
|
private final class SubMap extends AbstractMap implements SortedMap
|
|
{
|
|
/**
|
|
* The lower range of this view, inclusive, or nil for unbounded.
|
|
* Package visible for use by nested classes.
|
|
*/
|
|
final Object minKey;
|
|
|
|
/**
|
|
* The upper range of this view, exclusive, or nil for unbounded.
|
|
* Package visible for use by nested classes.
|
|
*/
|
|
final Object maxKey;
|
|
|
|
/**
|
|
* The cache for {@link #entrySet()}.
|
|
*/
|
|
private Set entries;
|
|
|
|
/**
|
|
* Create a SubMap representing the elements between minKey (inclusive)
|
|
* and maxKey (exclusive). If minKey is nil, SubMap has no lower bound
|
|
* (headMap). If maxKey is nil, the SubMap has no upper bound (tailMap).
|
|
*
|
|
* @param minKey the lower bound
|
|
* @param maxKey the upper bound
|
|
* @throws IllegalArgumentException if minKey > maxKey
|
|
*/
|
|
SubMap(Object minKey, Object maxKey)
|
|
{
|
|
if (minKey != nil && maxKey != nil && compare(minKey, maxKey) > 0)
|
|
throw new IllegalArgumentException("fromKey > toKey");
|
|
this.minKey = minKey;
|
|
this.maxKey = maxKey;
|
|
}
|
|
|
|
/**
|
|
* Check if "key" is in within the range bounds for this SubMap. The
|
|
* lower ("from") SubMap range is inclusive, and the upper ("to") bound
|
|
* is exclusive. Package visible for use by nested classes.
|
|
*
|
|
* @param key the key to check
|
|
* @return true if the key is in range
|
|
*/
|
|
boolean keyInRange(Object key)
|
|
{
|
|
return ((minKey == nil || compare(key, minKey) >= 0)
|
|
&& (maxKey == nil || compare(key, maxKey) < 0));
|
|
}
|
|
|
|
public void clear()
|
|
{
|
|
Node next = lowestGreaterThan(minKey, true);
|
|
Node max = lowestGreaterThan(maxKey, false);
|
|
while (next != max)
|
|
{
|
|
Node current = next;
|
|
next = successor(current);
|
|
removeNode(current);
|
|
}
|
|
}
|
|
|
|
public Comparator comparator()
|
|
{
|
|
return comparator;
|
|
}
|
|
|
|
public boolean containsKey(Object key)
|
|
{
|
|
return keyInRange(key) && TreeMap.this.containsKey(key);
|
|
}
|
|
|
|
public boolean containsValue(Object value)
|
|
{
|
|
Node node = lowestGreaterThan(minKey, true);
|
|
Node max = lowestGreaterThan(maxKey, false);
|
|
while (node != max)
|
|
{
|
|
if (equals(value, node.getValue()))
|
|
return true;
|
|
node = successor(node);
|
|
}
|
|
return false;
|
|
}
|
|
|
|
public Set entrySet()
|
|
{
|
|
if (entries == null)
|
|
// Create an AbstractSet with custom implementations of those methods
|
|
// that can be overriden easily and efficiently.
|
|
entries = new AbstractSet()
|
|
{
|
|
public int size()
|
|
{
|
|
return SubMap.this.size();
|
|
}
|
|
|
|
public Iterator iterator()
|
|
{
|
|
Node first = lowestGreaterThan(minKey, true);
|
|
Node max = lowestGreaterThan(maxKey, false);
|
|
return new TreeIterator(ENTRIES, first, max);
|
|
}
|
|
|
|
public void clear()
|
|
{
|
|
SubMap.this.clear();
|
|
}
|
|
|
|
public boolean contains(Object o)
|
|
{
|
|
if (! (o instanceof Map.Entry))
|
|
return false;
|
|
Map.Entry me = (Map.Entry) o;
|
|
Object key = me.getKey();
|
|
if (! keyInRange(key))
|
|
return false;
|
|
Node n = getNode(key);
|
|
return n != nil && AbstractSet.equals(me.getValue(), n.value);
|
|
}
|
|
|
|
public boolean remove(Object o)
|
|
{
|
|
if (! (o instanceof Map.Entry))
|
|
return false;
|
|
Map.Entry me = (Map.Entry) o;
|
|
Object key = me.getKey();
|
|
if (! keyInRange(key))
|
|
return false;
|
|
Node n = getNode(key);
|
|
if (n != nil && AbstractSet.equals(me.getValue(), n.value))
|
|
{
|
|
removeNode(n);
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
};
|
|
return entries;
|
|
}
|
|
|
|
public Object firstKey()
|
|
{
|
|
Node node = lowestGreaterThan(minKey, true);
|
|
if (node == nil || ! keyInRange(node.key))
|
|
throw new NoSuchElementException();
|
|
return node.key;
|
|
}
|
|
|
|
public Object get(Object key)
|
|
{
|
|
if (keyInRange(key))
|
|
return TreeMap.this.get(key);
|
|
return null;
|
|
}
|
|
|
|
public SortedMap headMap(Object toKey)
|
|
{
|
|
if (! keyInRange(toKey))
|
|
throw new IllegalArgumentException("key outside range");
|
|
return new SubMap(minKey, toKey);
|
|
}
|
|
|
|
public Set keySet()
|
|
{
|
|
if (this.keys == null)
|
|
// Create an AbstractSet with custom implementations of those methods
|
|
// that can be overriden easily and efficiently.
|
|
this.keys = new AbstractSet()
|
|
{
|
|
public int size()
|
|
{
|
|
return SubMap.this.size();
|
|
}
|
|
|
|
public Iterator iterator()
|
|
{
|
|
Node first = lowestGreaterThan(minKey, true);
|
|
Node max = lowestGreaterThan(maxKey, false);
|
|
return new TreeIterator(KEYS, first, max);
|
|
}
|
|
|
|
public void clear()
|
|
{
|
|
SubMap.this.clear();
|
|
}
|
|
|
|
public boolean contains(Object o)
|
|
{
|
|
if (! keyInRange(o))
|
|
return false;
|
|
return getNode(o) != nil;
|
|
}
|
|
|
|
public boolean remove(Object o)
|
|
{
|
|
if (! keyInRange(o))
|
|
return false;
|
|
Node n = getNode(o);
|
|
if (n != nil)
|
|
{
|
|
removeNode(n);
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
};
|
|
return this.keys;
|
|
}
|
|
|
|
public Object lastKey()
|
|
{
|
|
Node node = highestLessThan(maxKey);
|
|
if (node == nil || ! keyInRange(node.key))
|
|
throw new NoSuchElementException();
|
|
return node.key;
|
|
}
|
|
|
|
public Object put(Object key, Object value)
|
|
{
|
|
if (! keyInRange(key))
|
|
throw new IllegalArgumentException("Key outside range");
|
|
return TreeMap.this.put(key, value);
|
|
}
|
|
|
|
public Object remove(Object key)
|
|
{
|
|
if (keyInRange(key))
|
|
return TreeMap.this.remove(key);
|
|
return null;
|
|
}
|
|
|
|
public int size()
|
|
{
|
|
Node node = lowestGreaterThan(minKey, true);
|
|
Node max = lowestGreaterThan(maxKey, false);
|
|
int count = 0;
|
|
while (node != max)
|
|
{
|
|
count++;
|
|
node = successor(node);
|
|
}
|
|
return count;
|
|
}
|
|
|
|
public SortedMap subMap(Object fromKey, Object toKey)
|
|
{
|
|
if (! keyInRange(fromKey) || ! keyInRange(toKey))
|
|
throw new IllegalArgumentException("key outside range");
|
|
return new SubMap(fromKey, toKey);
|
|
}
|
|
|
|
public SortedMap tailMap(Object fromKey)
|
|
{
|
|
if (! keyInRange(fromKey))
|
|
throw new IllegalArgumentException("key outside range");
|
|
return new SubMap(fromKey, maxKey);
|
|
}
|
|
|
|
public Collection values()
|
|
{
|
|
if (this.values == null)
|
|
// Create an AbstractCollection with custom implementations of those
|
|
// methods that can be overriden easily and efficiently.
|
|
this.values = new AbstractCollection()
|
|
{
|
|
public int size()
|
|
{
|
|
return SubMap.this.size();
|
|
}
|
|
|
|
public Iterator iterator()
|
|
{
|
|
Node first = lowestGreaterThan(minKey, true);
|
|
Node max = lowestGreaterThan(maxKey, false);
|
|
return new TreeIterator(VALUES, first, max);
|
|
}
|
|
|
|
public void clear()
|
|
{
|
|
SubMap.this.clear();
|
|
}
|
|
};
|
|
return this.values;
|
|
}
|
|
} // class SubMap
|
|
} // class TreeMap
|