1226 lines
43 KiB
Java
1226 lines
43 KiB
Java
/* AbstractList.java -- Abstract implementation of most of List
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Copyright (C) 1998, 1999, 2000, 2001, 2002, 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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/**
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* A basic implementation of most of the methods in the List interface to make
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* it easier to create a List based on a random-access data structure. If
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* the list is sequential (such as a linked list), use AbstractSequentialList.
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* To create an unmodifiable list, it is only necessary to override the
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* size() and get(int) methods (this contrasts with all other abstract
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* collection classes which require an iterator to be provided). To make the
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* list modifiable, the set(int, Object) method should also be overridden, and
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* to make the list resizable, the add(int, Object) and remove(int) methods
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* should be overridden too. Other methods should be overridden if the
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* backing data structure allows for a more efficient implementation.
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* The precise implementation used by AbstractList is documented, so that
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* subclasses can tell which methods could be implemented more efficiently.
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* <p>
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*
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* As recommended by Collection and List, the subclass should provide at
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* least a no-argument and a Collection constructor. This class is not
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* synchronized.
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*
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* @author Original author unknown
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* @author Bryce McKinlay
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* @author Eric Blake (ebb9@email.byu.edu)
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* @see Collection
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* @see List
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* @see AbstractSequentialList
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* @see AbstractCollection
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* @see ListIterator
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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 abstract class AbstractList extends AbstractCollection implements List
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{
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/**
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* A count of the number of structural modifications that have been made to
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* the list (that is, insertions and removals). Structural modifications
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* are ones which change the list size or affect how iterations would
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* behave. This field is available for use by Iterator and ListIterator,
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* in order to throw a {@link ConcurrentModificationException} in response
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* to the next operation on the iterator. This <i>fail-fast</i> behavior
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* saves the user from many subtle bugs otherwise possible from concurrent
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* modification during iteration.
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* <p>
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*
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* To make lists fail-fast, increment this field by just 1 in the
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* <code>add(int, Object)</code> and <code>remove(int)</code> methods.
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* Otherwise, this field may be ignored.
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*/
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protected transient int modCount;
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/**
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* The main constructor, for use by subclasses.
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*/
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protected AbstractList()
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{
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}
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/**
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* Returns the elements at the specified position in the list.
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*
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* @param index the element to return
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* @return the element at that position
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* @throws IndexOutOfBoundsException if index < 0 || index >= size()
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*/
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public abstract Object get(int index);
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/**
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* Insert an element into the list at a given position (optional operation).
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* This shifts all existing elements from that position to the end one
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* index to the right. This version of add has no return, since it is
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* assumed to always succeed if there is no exception. This implementation
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* always throws UnsupportedOperationException, and must be overridden to
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* make a modifiable List. If you want fail-fast iterators, be sure to
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* increment modCount when overriding this.
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*
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* @param index the location to insert the item
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* @param o the object to insert
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* @throws UnsupportedOperationException if this list does not support the
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* add operation
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* @throws IndexOutOfBoundsException if index < 0 || index > size()
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* @throws ClassCastException if o cannot be added to this list due to its
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* type
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* @throws IllegalArgumentException if o cannot be added to this list for
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* some other reason
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* @see #modCount
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*/
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public void add(int index, Object o)
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{
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throw new UnsupportedOperationException();
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}
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/**
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* Add an element to the end of the list (optional operation). If the list
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* imposes restraints on what can be inserted, such as no null elements,
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* this should be documented. This implementation calls
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* <code>add(size(), o);</code>, and will fail if that version does.
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*
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* @param o the object to add
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* @return true, as defined by Collection for a modified list
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* @throws UnsupportedOperationException if this list does not support the
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* add operation
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* @throws ClassCastException if o cannot be added to this list due to its
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* type
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* @throws IllegalArgumentException if o cannot be added to this list for
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* some other reason
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* @see #add(int, Object)
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*/
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public boolean add(Object o)
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{
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add(size(), o);
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return true;
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}
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/**
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* Insert the contents of a collection into the list at a given position
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* (optional operation). Shift all elements at that position to the right
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* by the number of elements inserted. This operation is undefined if
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* this list is modified during the operation (for example, if you try
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* to insert a list into itself). This implementation uses the iterator of
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* the collection, repeatedly calling add(int, Object); this will fail
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* if add does. This can often be made more efficient.
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*
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* @param index the location to insert the collection
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* @param c the collection to insert
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* @return true if the list was modified by this action, that is, if c is
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* non-empty
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* @throws UnsupportedOperationException if this list does not support the
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* addAll operation
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* @throws IndexOutOfBoundsException if index < 0 || index > size()
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* @throws ClassCastException if some element of c cannot be added to this
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* list due to its type
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* @throws IllegalArgumentException if some element of c cannot be added
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* to this list for some other reason
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* @throws NullPointerException if the specified collection is null
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* @see #add(int, Object)
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*/
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public boolean addAll(int index, Collection c)
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{
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Iterator itr = c.iterator();
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int size = c.size();
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for (int pos = size; pos > 0; pos--)
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add(index++, itr.next());
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return size > 0;
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}
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/**
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* Clear the list, such that a subsequent call to isEmpty() would return
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* true (optional operation). This implementation calls
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* <code>removeRange(0, size())</code>, so it will fail unless remove
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* or removeRange is overridden.
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*
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* @throws UnsupportedOperationException if this list does not support the
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* clear operation
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* @see #remove(int)
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* @see #removeRange(int, int)
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*/
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public void clear()
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{
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removeRange(0, size());
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}
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/**
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* Test whether this list is equal to another object. A List is defined to be
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* equal to an object if and only if that object is also a List, and the two
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* lists have the same sequence. Two lists l1 and l2 are equal if and only
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* if <code>l1.size() == l2.size()</code>, and for every integer n between 0
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* and <code>l1.size() - 1</code> inclusive, <code>l1.get(n) == null ?
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* l2.get(n) == null : l1.get(n).equals(l2.get(n))</code>.
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* <p>
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*
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* This implementation returns true if the object is this, or false if the
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* object is not a List. Otherwise, it iterates over both lists (with
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* iterator()), returning false if two elements compare false or one list
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* is shorter, and true if the iteration completes successfully.
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*
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* @param o the object to test for equality with this list
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* @return true if o is equal to this list
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* @see Object#equals(Object)
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* @see #hashCode()
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*/
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public boolean equals(Object o)
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{
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if (o == this)
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return true;
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if (! (o instanceof List))
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return false;
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int size = size();
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if (size != ((List) o).size())
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return false;
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Iterator itr1 = iterator();
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Iterator itr2 = ((List) o).iterator();
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while (--size >= 0)
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if (! equals(itr1.next(), itr2.next()))
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return false;
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return true;
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}
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/**
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* Obtains a hash code for this list. In order to obey the general
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* contract of the hashCode method of class Object, this value is
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* calculated as follows:
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*
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<pre>hashCode = 1;
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Iterator i = list.iterator();
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while (i.hasNext())
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{
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Object obj = i.next();
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hashCode = 31 * hashCode + (obj == null ? 0 : obj.hashCode());
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}</pre>
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*
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* This ensures that the general contract of Object.hashCode() is adhered to.
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*
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* @return the hash code of this list
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*
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* @see Object#hashCode()
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* @see #equals(Object)
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*/
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public int hashCode()
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{
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int hashCode = 1;
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Iterator itr = iterator();
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int pos = size();
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while (--pos >= 0)
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hashCode = 31 * hashCode + hashCode(itr.next());
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return hashCode;
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}
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/**
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* Obtain the first index at which a given object is to be found in this
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* list. This implementation follows a listIterator() until a match is found,
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* or returns -1 if the list end is reached.
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*
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* @param o the object to search for
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* @return the least integer n such that <code>o == null ? get(n) == null :
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* o.equals(get(n))</code>, or -1 if there is no such index
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*/
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public int indexOf(Object o)
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{
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ListIterator itr = listIterator();
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int size = size();
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for (int pos = 0; pos < size; pos++)
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if (equals(o, itr.next()))
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return pos;
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return -1;
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}
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/**
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* Obtain an Iterator over this list, whose sequence is the list order.
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* This implementation uses size(), get(int), and remove(int) of the
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* backing list, and does not support remove unless the list does. This
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* implementation is fail-fast if you correctly maintain modCount.
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* Also, this implementation is specified by Sun to be distinct from
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* listIterator, although you could easily implement it as
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* <code>return listIterator(0)</code>.
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*
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* @return an Iterator over the elements of this list, in order
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* @see #modCount
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*/
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public Iterator iterator()
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{
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// Bah, Sun's implementation forbids using listIterator(0).
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return new Iterator()
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{
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private int pos = 0;
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private int size = size();
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private int last = -1;
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private int knownMod = modCount;
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// This will get inlined, since it is private.
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/**
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* Checks for modifications made to the list from
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* elsewhere while iteration is in progress.
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*
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* @throws ConcurrentModificationException if the
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* list has been modified elsewhere.
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*/
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private void checkMod()
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{
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if (knownMod != modCount)
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throw new ConcurrentModificationException();
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}
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/**
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* Tests to see if there are any more objects to
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* return.
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*
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* @return True if the end of the list has not yet been
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* reached.
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* @throws ConcurrentModificationException if the
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* list has been modified elsewhere.
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*/
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public boolean hasNext()
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{
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checkMod();
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return pos < size;
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}
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/**
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* Retrieves the next object from the list.
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*
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* @return The next object.
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* @throws NoSuchElementException if there are
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* no more objects to retrieve.
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* @throws ConcurrentModificationException if the
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* list has been modified elsewhere.
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*/
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public Object next()
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{
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checkMod();
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if (pos == size)
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throw new NoSuchElementException();
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last = pos;
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return get(pos++);
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}
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/**
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* Removes the last object retrieved by <code>next()</code>
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* from the list, if the list supports object removal.
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*
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* @throws ConcurrentModificationException if the list
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* has been modified elsewhere.
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* @throws IllegalStateException if the iterator is positioned
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* before the start of the list or the last object has already
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* been removed.
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* @throws UnsupportedOperationException if the list does
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* not support removing elements.
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*/
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public void remove()
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{
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checkMod();
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if (last < 0)
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throw new IllegalStateException();
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AbstractList.this.remove(last);
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pos--;
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size--;
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last = -1;
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knownMod = modCount;
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}
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};
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}
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/**
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* Obtain the last index at which a given object is to be found in this
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* list. This implementation grabs listIterator(size()), then searches
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* backwards for a match or returns -1.
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*
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* @return the greatest integer n such that <code>o == null ? get(n) == null
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* : o.equals(get(n))</code>, or -1 if there is no such index
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*/
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public int lastIndexOf(Object o)
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{
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int pos = size();
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ListIterator itr = listIterator(pos);
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while (--pos >= 0)
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if (equals(o, itr.previous()))
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return pos;
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return -1;
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}
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/**
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* Obtain a ListIterator over this list, starting at the beginning. This
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* implementation returns listIterator(0).
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*
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* @return a ListIterator over the elements of this list, in order, starting
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* at the beginning
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*/
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public ListIterator listIterator()
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{
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return listIterator(0);
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}
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/**
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* Obtain a ListIterator over this list, starting at a given position.
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* A first call to next() would return the same as get(index), and a
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* first call to previous() would return the same as get(index - 1).
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* <p>
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*
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* This implementation uses size(), get(int), set(int, Object),
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* add(int, Object), and remove(int) of the backing list, and does not
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* support remove, set, or add unless the list does. This implementation
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* is fail-fast if you correctly maintain modCount.
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*
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* @param index the position, between 0 and size() inclusive, to begin the
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* iteration from
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* @return a ListIterator over the elements of this list, in order, starting
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* at index
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* @throws IndexOutOfBoundsException if index < 0 || index > size()
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* @see #modCount
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*/
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public ListIterator listIterator(final int index)
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{
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if (index < 0 || index > size())
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throw new IndexOutOfBoundsException("Index: " + index + ", Size:"
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+ size());
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return new ListIterator()
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{
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private int knownMod = modCount;
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private int position = index;
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private int lastReturned = -1;
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private int size = size();
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// This will get inlined, since it is private.
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/**
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* Checks for modifications made to the list from
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* elsewhere while iteration is in progress.
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*
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* @throws ConcurrentModificationException if the
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* list has been modified elsewhere.
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*/
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private void checkMod()
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{
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if (knownMod != modCount)
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throw new ConcurrentModificationException();
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}
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|
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/**
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* Tests to see if there are any more objects to
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* return.
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*
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* @return True if the end of the list has not yet been
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* reached.
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* @throws ConcurrentModificationException if the
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* list has been modified elsewhere.
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*/
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public boolean hasNext()
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{
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checkMod();
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return position < size;
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}
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|
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/**
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* Tests to see if there are objects prior to the
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* current position in the list.
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*
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* @return True if objects exist prior to the current
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* position of the iterator.
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* @throws ConcurrentModificationException if the
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* list has been modified elsewhere.
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*/
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public boolean hasPrevious()
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{
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checkMod();
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return position > 0;
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}
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|
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/**
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* Retrieves the next object from the list.
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*
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* @return The next object.
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* @throws NoSuchElementException if there are no
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* more objects to retrieve.
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* @throws ConcurrentModificationException if the
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* list has been modified elsewhere.
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*/
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public Object next()
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{
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checkMod();
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if (position == size)
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throw new NoSuchElementException();
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lastReturned = position;
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return get(position++);
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}
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/**
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* Retrieves the previous object from the list.
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*
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* @return The next object.
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* @throws NoSuchElementException if there are no
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* previous objects to retrieve.
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* @throws ConcurrentModificationException if the
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* list has been modified elsewhere.
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*/
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public Object previous()
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{
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checkMod();
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if (position == 0)
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throw new NoSuchElementException();
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lastReturned = --position;
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return get(lastReturned);
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}
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/**
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* Returns the index of the next element in the
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* list, which will be retrieved by <code>next()</code>
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*
|
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* @return The index of the next element.
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* @throws ConcurrentModificationException if the list
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* has been modified elsewhere.
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*/
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public int nextIndex()
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{
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checkMod();
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return position;
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}
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|
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/**
|
|
* Returns the index of the previous element in the
|
|
* list, which will be retrieved by <code>previous()</code>
|
|
*
|
|
* @return The index of the previous element.
|
|
* @throws ConcurrentModificationException if the list
|
|
* has been modified elsewhere.
|
|
*/
|
|
public int previousIndex()
|
|
{
|
|
checkMod();
|
|
return position - 1;
|
|
}
|
|
|
|
/**
|
|
* Removes the last object retrieved by <code>next()</code>
|
|
* or <code>previous()</code> from the list, if the list
|
|
* supports object removal.
|
|
*
|
|
* @throws IllegalStateException if the iterator is positioned
|
|
* before the start of the list or the last object has already
|
|
* been removed.
|
|
* @throws UnsupportedOperationException if the list does
|
|
* not support removing elements.
|
|
* @throws ConcurrentModificationException if the list
|
|
* has been modified elsewhere.
|
|
*/
|
|
public void remove()
|
|
{
|
|
checkMod();
|
|
if (lastReturned < 0)
|
|
throw new IllegalStateException();
|
|
AbstractList.this.remove(lastReturned);
|
|
size--;
|
|
position = lastReturned;
|
|
lastReturned = -1;
|
|
knownMod = modCount;
|
|
}
|
|
|
|
/**
|
|
* Replaces the last object retrieved by <code>next()</code>
|
|
* or <code>previous</code> with o, if the list supports object
|
|
* replacement and an add or remove operation has not already
|
|
* been performed.
|
|
*
|
|
* @throws IllegalStateException if the iterator is positioned
|
|
* before the start of the list or the last object has already
|
|
* been removed.
|
|
* @throws UnsupportedOperationException if the list doesn't support
|
|
* the addition or removal of elements.
|
|
* @throws ClassCastException if the type of o is not a valid type
|
|
* for this list.
|
|
* @throws IllegalArgumentException if something else related to o
|
|
* prevents its addition.
|
|
* @throws ConcurrentModificationException if the list
|
|
* has been modified elsewhere.
|
|
*/
|
|
public void set(Object o)
|
|
{
|
|
checkMod();
|
|
if (lastReturned < 0)
|
|
throw new IllegalStateException();
|
|
AbstractList.this.set(lastReturned, o);
|
|
}
|
|
|
|
/**
|
|
* Adds the supplied object before the element that would be returned
|
|
* by a call to <code>next()</code>, if the list supports addition.
|
|
*
|
|
* @param o The object to add to the list.
|
|
* @throws UnsupportedOperationException if the list doesn't support
|
|
* the addition of new elements.
|
|
* @throws ClassCastException if the type of o is not a valid type
|
|
* for this list.
|
|
* @throws IllegalArgumentException if something else related to o
|
|
* prevents its addition.
|
|
* @throws ConcurrentModificationException if the list
|
|
* has been modified elsewhere.
|
|
*/
|
|
public void add(Object o)
|
|
{
|
|
checkMod();
|
|
AbstractList.this.add(position++, o);
|
|
size++;
|
|
lastReturned = -1;
|
|
knownMod = modCount;
|
|
}
|
|
};
|
|
}
|
|
|
|
/**
|
|
* Remove the element at a given position in this list (optional operation).
|
|
* Shifts all remaining elements to the left to fill the gap. This
|
|
* implementation always throws an UnsupportedOperationException.
|
|
* If you want fail-fast iterators, be sure to increment modCount when
|
|
* overriding this.
|
|
*
|
|
* @param index the position within the list of the object to remove
|
|
* @return the object that was removed
|
|
* @throws UnsupportedOperationException if this list does not support the
|
|
* remove operation
|
|
* @throws IndexOutOfBoundsException if index < 0 || index >= size()
|
|
* @see #modCount
|
|
*/
|
|
public Object remove(int index)
|
|
{
|
|
throw new UnsupportedOperationException();
|
|
}
|
|
|
|
/**
|
|
* Remove a subsection of the list. This is called by the clear and
|
|
* removeRange methods of the class which implements subList, which are
|
|
* difficult for subclasses to override directly. Therefore, this method
|
|
* should be overridden instead by the more efficient implementation, if one
|
|
* exists. Overriding this can reduce quadratic efforts to constant time
|
|
* in some cases!
|
|
* <p>
|
|
*
|
|
* This implementation first checks for illegal or out of range arguments. It
|
|
* then obtains a ListIterator over the list using listIterator(fromIndex).
|
|
* It then calls next() and remove() on this iterator repeatedly, toIndex -
|
|
* fromIndex times.
|
|
*
|
|
* @param fromIndex the index, inclusive, to remove from.
|
|
* @param toIndex the index, exclusive, to remove to.
|
|
* @throws UnsupportedOperationException if the list does
|
|
* not support removing elements.
|
|
*/
|
|
protected void removeRange(int fromIndex, int toIndex)
|
|
{
|
|
ListIterator itr = listIterator(fromIndex);
|
|
for (int index = fromIndex; index < toIndex; index++)
|
|
{
|
|
itr.next();
|
|
itr.remove();
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Replace an element of this list with another object (optional operation).
|
|
* This implementation always throws an UnsupportedOperationException.
|
|
*
|
|
* @param index the position within this list of the element to be replaced
|
|
* @param o the object to replace it with
|
|
* @return the object that was replaced
|
|
* @throws UnsupportedOperationException if this list does not support the
|
|
* set operation
|
|
* @throws IndexOutOfBoundsException if index < 0 || index >= size()
|
|
* @throws ClassCastException if o cannot be added to this list due to its
|
|
* type
|
|
* @throws IllegalArgumentException if o cannot be added to this list for
|
|
* some other reason
|
|
*/
|
|
public Object set(int index, Object o)
|
|
{
|
|
throw new UnsupportedOperationException();
|
|
}
|
|
|
|
/**
|
|
* Obtain a List view of a subsection of this list, from fromIndex
|
|
* (inclusive) to toIndex (exclusive). If the two indices are equal, the
|
|
* sublist is empty. The returned list should be modifiable if and only
|
|
* if this list is modifiable. Changes to the returned list should be
|
|
* reflected in this list. If this list is structurally modified in
|
|
* any way other than through the returned list, the result of any subsequent
|
|
* operations on the returned list is undefined.
|
|
* <p>
|
|
*
|
|
* This implementation returns a subclass of AbstractList. It stores, in
|
|
* private fields, the offset and size of the sublist, and the expected
|
|
* modCount of the backing list. If the backing list implements RandomAccess,
|
|
* the sublist will also.
|
|
* <p>
|
|
*
|
|
* The subclass's <code>set(int, Object)</code>, <code>get(int)</code>,
|
|
* <code>add(int, Object)</code>, <code>remove(int)</code>,
|
|
* <code>addAll(int, Collection)</code> and
|
|
* <code>removeRange(int, int)</code> methods all delegate to the
|
|
* corresponding methods on the backing abstract list, after
|
|
* bounds-checking the index and adjusting for the offset. The
|
|
* <code>addAll(Collection c)</code> method merely returns addAll(size, c).
|
|
* The <code>listIterator(int)</code> method returns a "wrapper object"
|
|
* over a list iterator on the backing list, which is created with the
|
|
* corresponding method on the backing list. The <code>iterator()</code>
|
|
* method merely returns listIterator(), and the <code>size()</code> method
|
|
* merely returns the subclass's size field.
|
|
* <p>
|
|
*
|
|
* All methods first check to see if the actual modCount of the backing
|
|
* list is equal to its expected value, and throw a
|
|
* ConcurrentModificationException if it is not.
|
|
*
|
|
* @param fromIndex the index that the returned list should start from
|
|
* (inclusive)
|
|
* @param toIndex the index that the returned list should go to (exclusive)
|
|
* @return a List backed by a subsection of this list
|
|
* @throws IndexOutOfBoundsException if fromIndex < 0
|
|
* || toIndex > size()
|
|
* @throws IllegalArgumentException if fromIndex > toIndex
|
|
* @see ConcurrentModificationException
|
|
* @see RandomAccess
|
|
*/
|
|
public List subList(int fromIndex, int toIndex)
|
|
{
|
|
// This follows the specification of AbstractList, but is inconsistent
|
|
// with the one in List. Don't you love Sun's inconsistencies?
|
|
if (fromIndex > toIndex)
|
|
throw new IllegalArgumentException(fromIndex + " > " + toIndex);
|
|
if (fromIndex < 0 || toIndex > size())
|
|
throw new IndexOutOfBoundsException();
|
|
|
|
if (this instanceof RandomAccess)
|
|
return new RandomAccessSubList(this, fromIndex, toIndex);
|
|
return new SubList(this, fromIndex, toIndex);
|
|
}
|
|
|
|
/**
|
|
* This class follows the implementation requirements set forth in
|
|
* {@link AbstractList#subList(int, int)}. It matches Sun's implementation
|
|
* by using a non-public top-level class in the same package.
|
|
*
|
|
* @author Original author unknown
|
|
* @author Eric Blake (ebb9@email.byu.edu)
|
|
*/
|
|
private static class SubList extends AbstractList
|
|
{
|
|
// Package visible, for use by iterator.
|
|
/** The original list. */
|
|
final AbstractList backingList;
|
|
/** The index of the first element of the sublist. */
|
|
final int offset;
|
|
/** The size of the sublist. */
|
|
int size;
|
|
|
|
/**
|
|
* Construct the sublist.
|
|
*
|
|
* @param backing the list this comes from
|
|
* @param fromIndex the lower bound, inclusive
|
|
* @param toIndex the upper bound, exclusive
|
|
*/
|
|
SubList(AbstractList backing, int fromIndex, int toIndex)
|
|
{
|
|
backingList = backing;
|
|
modCount = backing.modCount;
|
|
offset = fromIndex;
|
|
size = toIndex - fromIndex;
|
|
}
|
|
|
|
/**
|
|
* This method checks the two modCount fields to ensure that there has
|
|
* not been a concurrent modification, returning if all is okay.
|
|
*
|
|
* @throws ConcurrentModificationException if the backing list has been
|
|
* modified externally to this sublist
|
|
*/
|
|
// This can be inlined. Package visible, for use by iterator.
|
|
void checkMod()
|
|
{
|
|
if (modCount != backingList.modCount)
|
|
throw new ConcurrentModificationException();
|
|
}
|
|
|
|
/**
|
|
* This method checks that a value is between 0 and size (inclusive). If
|
|
* it is not, an exception is thrown.
|
|
*
|
|
* @param index the value to check
|
|
* @throws IndexOutOfBoundsException if index < 0 || index > size()
|
|
*/
|
|
// This will get inlined, since it is private.
|
|
private void checkBoundsInclusive(int index)
|
|
{
|
|
if (index < 0 || index > size)
|
|
throw new IndexOutOfBoundsException("Index: " + index + ", Size:"
|
|
+ size);
|
|
}
|
|
|
|
/**
|
|
* This method checks that a value is between 0 (inclusive) and size
|
|
* (exclusive). If it is not, an exception is thrown.
|
|
*
|
|
* @param index the value to check
|
|
* @throws IndexOutOfBoundsException if index < 0 || index >= size()
|
|
*/
|
|
// This will get inlined, since it is private.
|
|
private void checkBoundsExclusive(int index)
|
|
{
|
|
if (index < 0 || index >= size)
|
|
throw new IndexOutOfBoundsException("Index: " + index + ", Size:"
|
|
+ size);
|
|
}
|
|
|
|
/**
|
|
* Specified by AbstractList.subList to return the private field size.
|
|
*
|
|
* @return the sublist size
|
|
* @throws ConcurrentModificationException if the backing list has been
|
|
* modified externally to this sublist
|
|
*/
|
|
public int size()
|
|
{
|
|
checkMod();
|
|
return size;
|
|
}
|
|
|
|
/**
|
|
* Specified by AbstractList.subList to delegate to the backing list.
|
|
*
|
|
* @param index the location to modify
|
|
* @param o the new value
|
|
* @return the old value
|
|
* @throws ConcurrentModificationException if the backing list has been
|
|
* modified externally to this sublist
|
|
* @throws UnsupportedOperationException if the backing list does not
|
|
* support the set operation
|
|
* @throws IndexOutOfBoundsException if index < 0 || index >= size()
|
|
* @throws ClassCastException if o cannot be added to the backing list due
|
|
* to its type
|
|
* @throws IllegalArgumentException if o cannot be added to the backing list
|
|
* for some other reason
|
|
*/
|
|
public Object set(int index, Object o)
|
|
{
|
|
checkMod();
|
|
checkBoundsExclusive(index);
|
|
return backingList.set(index + offset, o);
|
|
}
|
|
|
|
/**
|
|
* Specified by AbstractList.subList to delegate to the backing list.
|
|
*
|
|
* @param index the location to get from
|
|
* @return the object at that location
|
|
* @throws ConcurrentModificationException if the backing list has been
|
|
* modified externally to this sublist
|
|
* @throws IndexOutOfBoundsException if index < 0 || index >= size()
|
|
*/
|
|
public Object get(int index)
|
|
{
|
|
checkMod();
|
|
checkBoundsExclusive(index);
|
|
return backingList.get(index + offset);
|
|
}
|
|
|
|
/**
|
|
* Specified by AbstractList.subList to delegate to the backing list.
|
|
*
|
|
* @param index the index to insert at
|
|
* @param o the object to add
|
|
* @throws ConcurrentModificationException if the backing list has been
|
|
* modified externally to this sublist
|
|
* @throws IndexOutOfBoundsException if index < 0 || index > size()
|
|
* @throws UnsupportedOperationException if the backing list does not
|
|
* support the add operation.
|
|
* @throws ClassCastException if o cannot be added to the backing list due
|
|
* to its type.
|
|
* @throws IllegalArgumentException if o cannot be added to the backing
|
|
* list for some other reason.
|
|
*/
|
|
public void add(int index, Object o)
|
|
{
|
|
checkMod();
|
|
checkBoundsInclusive(index);
|
|
backingList.add(index + offset, o);
|
|
size++;
|
|
modCount = backingList.modCount;
|
|
}
|
|
|
|
/**
|
|
* Specified by AbstractList.subList to delegate to the backing list.
|
|
*
|
|
* @param index the index to remove
|
|
* @return the removed object
|
|
* @throws ConcurrentModificationException if the backing list has been
|
|
* modified externally to this sublist
|
|
* @throws IndexOutOfBoundsException if index < 0 || index >= size()
|
|
* @throws UnsupportedOperationException if the backing list does not
|
|
* support the remove operation
|
|
*/
|
|
public Object remove(int index)
|
|
{
|
|
checkMod();
|
|
checkBoundsExclusive(index);
|
|
Object o = backingList.remove(index + offset);
|
|
size--;
|
|
modCount = backingList.modCount;
|
|
return o;
|
|
}
|
|
|
|
/**
|
|
* Specified by AbstractList.subList to delegate to the backing list.
|
|
* This does no bounds checking, as it assumes it will only be called
|
|
* by trusted code like clear() which has already checked the bounds.
|
|
*
|
|
* @param fromIndex the lower bound, inclusive
|
|
* @param toIndex the upper bound, exclusive
|
|
* @throws ConcurrentModificationException if the backing list has been
|
|
* modified externally to this sublist
|
|
* @throws UnsupportedOperationException if the backing list does
|
|
* not support removing elements.
|
|
*/
|
|
protected void removeRange(int fromIndex, int toIndex)
|
|
{
|
|
checkMod();
|
|
|
|
backingList.removeRange(offset + fromIndex, offset + toIndex);
|
|
size -= toIndex - fromIndex;
|
|
modCount = backingList.modCount;
|
|
}
|
|
|
|
/**
|
|
* Specified by AbstractList.subList to delegate to the backing list.
|
|
*
|
|
* @param index the location to insert at
|
|
* @param c the collection to insert
|
|
* @return true if this list was modified, in other words, c is non-empty
|
|
* @throws ConcurrentModificationException if the backing list has been
|
|
* modified externally to this sublist
|
|
* @throws IndexOutOfBoundsException if index < 0 || index > size()
|
|
* @throws UnsupportedOperationException if this list does not support the
|
|
* addAll operation
|
|
* @throws ClassCastException if some element of c cannot be added to this
|
|
* list due to its type
|
|
* @throws IllegalArgumentException if some element of c cannot be added
|
|
* to this list for some other reason
|
|
* @throws NullPointerException if the specified collection is null
|
|
*/
|
|
public boolean addAll(int index, Collection c)
|
|
{
|
|
checkMod();
|
|
checkBoundsInclusive(index);
|
|
int csize = c.size();
|
|
boolean result = backingList.addAll(offset + index, c);
|
|
size += csize;
|
|
modCount = backingList.modCount;
|
|
return result;
|
|
}
|
|
|
|
/**
|
|
* Specified by AbstractList.subList to return addAll(size, c).
|
|
*
|
|
* @param c the collection to insert
|
|
* @return true if this list was modified, in other words, c is non-empty
|
|
* @throws ConcurrentModificationException if the backing list has been
|
|
* modified externally to this sublist
|
|
* @throws UnsupportedOperationException if this list does not support the
|
|
* addAll operation
|
|
* @throws ClassCastException if some element of c cannot be added to this
|
|
* list due to its type
|
|
* @throws IllegalArgumentException if some element of c cannot be added
|
|
* to this list for some other reason
|
|
* @throws NullPointerException if the specified collection is null
|
|
*/
|
|
public boolean addAll(Collection c)
|
|
{
|
|
return addAll(size, c);
|
|
}
|
|
|
|
/**
|
|
* Specified by AbstractList.subList to return listIterator().
|
|
*
|
|
* @return an iterator over the sublist
|
|
*/
|
|
public Iterator iterator()
|
|
{
|
|
return listIterator();
|
|
}
|
|
|
|
/**
|
|
* Specified by AbstractList.subList to return a wrapper around the
|
|
* backing list's iterator.
|
|
*
|
|
* @param index the start location of the iterator
|
|
* @return a list iterator over the sublist
|
|
* @throws ConcurrentModificationException if the backing list has been
|
|
* modified externally to this sublist
|
|
* @throws IndexOutOfBoundsException if the value is out of range
|
|
*/
|
|
public ListIterator listIterator(final int index)
|
|
{
|
|
checkMod();
|
|
checkBoundsInclusive(index);
|
|
|
|
return new ListIterator()
|
|
{
|
|
private final ListIterator i = backingList.listIterator(index + offset);
|
|
private int position = index;
|
|
|
|
/**
|
|
* Tests to see if there are any more objects to
|
|
* return.
|
|
*
|
|
* @return True if the end of the list has not yet been
|
|
* reached.
|
|
* @throws ConcurrentModificationException if the
|
|
* list has been modified elsewhere.
|
|
*/
|
|
public boolean hasNext()
|
|
{
|
|
checkMod();
|
|
return position < size;
|
|
}
|
|
|
|
/**
|
|
* Tests to see if there are objects prior to the
|
|
* current position in the list.
|
|
*
|
|
* @return True if objects exist prior to the current
|
|
* position of the iterator.
|
|
* @throws ConcurrentModificationException if the
|
|
* list has been modified elsewhere.
|
|
*/
|
|
public boolean hasPrevious()
|
|
{
|
|
checkMod();
|
|
return position > 0;
|
|
}
|
|
|
|
/**
|
|
* Retrieves the next object from the list.
|
|
*
|
|
* @return The next object.
|
|
* @throws NoSuchElementException if there are no
|
|
* more objects to retrieve.
|
|
* @throws ConcurrentModificationException if the
|
|
* list has been modified elsewhere.
|
|
*/
|
|
public Object next()
|
|
{
|
|
if (position == size)
|
|
throw new NoSuchElementException();
|
|
position++;
|
|
return i.next();
|
|
}
|
|
|
|
/**
|
|
* Retrieves the previous object from the list.
|
|
*
|
|
* @return The next object.
|
|
* @throws NoSuchElementException if there are no
|
|
* previous objects to retrieve.
|
|
* @throws ConcurrentModificationException if the
|
|
* list has been modified elsewhere.
|
|
*/
|
|
public Object previous()
|
|
{
|
|
if (position == 0)
|
|
throw new NoSuchElementException();
|
|
position--;
|
|
return i.previous();
|
|
}
|
|
|
|
/**
|
|
* Returns the index of the next element in the
|
|
* list, which will be retrieved by <code>next()</code>
|
|
*
|
|
* @return The index of the next element.
|
|
* @throws ConcurrentModificationException if the
|
|
* list has been modified elsewhere.
|
|
*/
|
|
public int nextIndex()
|
|
{
|
|
return i.nextIndex() - offset;
|
|
}
|
|
|
|
/**
|
|
* Returns the index of the previous element in the
|
|
* list, which will be retrieved by <code>previous()</code>
|
|
*
|
|
* @return The index of the previous element.
|
|
* @throws ConcurrentModificationException if the
|
|
* list has been modified elsewhere.
|
|
*/
|
|
public int previousIndex()
|
|
{
|
|
return i.previousIndex() - offset;
|
|
}
|
|
|
|
/**
|
|
* Removes the last object retrieved by <code>next()</code>
|
|
* from the list, if the list supports object removal.
|
|
*
|
|
* @throws IllegalStateException if the iterator is positioned
|
|
* before the start of the list or the last object has already
|
|
* been removed.
|
|
* @throws UnsupportedOperationException if the list does
|
|
* not support removing elements.
|
|
*/
|
|
public void remove()
|
|
{
|
|
i.remove();
|
|
size--;
|
|
position = nextIndex();
|
|
modCount = backingList.modCount;
|
|
}
|
|
|
|
|
|
/**
|
|
* Replaces the last object retrieved by <code>next()</code>
|
|
* or <code>previous</code> with o, if the list supports object
|
|
* replacement and an add or remove operation has not already
|
|
* been performed.
|
|
*
|
|
* @throws IllegalStateException if the iterator is positioned
|
|
* before the start of the list or the last object has already
|
|
* been removed.
|
|
* @throws UnsupportedOperationException if the list doesn't support
|
|
* the addition or removal of elements.
|
|
* @throws ClassCastException if the type of o is not a valid type
|
|
* for this list.
|
|
* @throws IllegalArgumentException if something else related to o
|
|
* prevents its addition.
|
|
* @throws ConcurrentModificationException if the list
|
|
* has been modified elsewhere.
|
|
*/
|
|
public void set(Object o)
|
|
{
|
|
i.set(o);
|
|
}
|
|
|
|
/**
|
|
* Adds the supplied object before the element that would be returned
|
|
* by a call to <code>next()</code>, if the list supports addition.
|
|
*
|
|
* @param o The object to add to the list.
|
|
* @throws UnsupportedOperationException if the list doesn't support
|
|
* the addition of new elements.
|
|
* @throws ClassCastException if the type of o is not a valid type
|
|
* for this list.
|
|
* @throws IllegalArgumentException if something else related to o
|
|
* prevents its addition.
|
|
* @throws ConcurrentModificationException if the list
|
|
* has been modified elsewhere.
|
|
*/
|
|
public void add(Object o)
|
|
{
|
|
i.add(o);
|
|
size++;
|
|
position++;
|
|
modCount = backingList.modCount;
|
|
}
|
|
|
|
// Here is the reason why the various modCount fields are mostly
|
|
// ignored in this wrapper listIterator.
|
|
// If the backing listIterator is failfast, then the following holds:
|
|
// Using any other method on this list will call a corresponding
|
|
// method on the backing list *after* the backing listIterator
|
|
// is created, which will in turn cause a ConcurrentModException
|
|
// when this listIterator comes to use the backing one. So it is
|
|
// implicitly failfast.
|
|
// If the backing listIterator is NOT failfast, then the whole of
|
|
// this list isn't failfast, because the modCount field of the
|
|
// backing list is not valid. It would still be *possible* to
|
|
// make the iterator failfast wrt modifications of the sublist
|
|
// only, but somewhat pointless when the list can be changed under
|
|
// us.
|
|
// Either way, no explicit handling of modCount is needed.
|
|
// However modCount = backingList.modCount must be executed in add
|
|
// and remove, and size must also be updated in these two methods,
|
|
// since they do not go through the corresponding methods of the subList.
|
|
};
|
|
}
|
|
} // class SubList
|
|
|
|
/**
|
|
* This class is a RandomAccess version of SubList, as required by
|
|
* {@link AbstractList#subList(int, int)}.
|
|
*
|
|
* @author Eric Blake (ebb9@email.byu.edu)
|
|
*/
|
|
private static final class RandomAccessSubList extends SubList
|
|
implements RandomAccess
|
|
{
|
|
/**
|
|
* Construct the sublist.
|
|
*
|
|
* @param backing the list this comes from
|
|
* @param fromIndex the lower bound, inclusive
|
|
* @param toIndex the upper bound, exclusive
|
|
*/
|
|
RandomAccessSubList(AbstractList backing, int fromIndex, int toIndex)
|
|
{
|
|
super(backing, fromIndex, toIndex);
|
|
}
|
|
} // class RandomAccessSubList
|
|
|
|
} // class AbstractList
|