177 lines
7.2 KiB
Java
177 lines
7.2 KiB
Java
/* SortedSet.java -- A set that makes guarantees about the order of its
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elements
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Copyright (C) 1998, 2001, 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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/**
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* A set which guarantees its iteration order. The elements in the set
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* are related by the <i>natural ordering</i> if they are Comparable, or
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* by the provided Comparator. Additional operations take advantage of
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* the sorted nature of the set.
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* <p>
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*
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* All elements entered in the set must be mutually comparable; in other words,
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* <code>k1.compareTo(k2)</code> or <code>comparator.compare(k1, k2)</code>
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* must not throw a ClassCastException. The ordering must be <i>consistent
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* with equals</i> (see {@link Comparator} for this definition), if the
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* set is to obey the general contract of the Set interface. If not,
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* the results are well-defined, but probably not what you wanted.
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* <p>
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*
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* It is recommended that all implementing classes provide four constructors:
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* 1) one that takes no arguments and builds an empty set sorted by natural
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* order of the elements; 2) one that takes a Comparator for the sorting order;
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* 3) one that takes a Set and sorts according to the natural order of its
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* elements; and 4) one that takes a SortedSet and sorts by the same
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* comparator. Unfortunately, the Java language does not provide a way to
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* enforce this.
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*
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* @author Original author unknown
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* @author Eric Blake (ebb9@email.byu.edu)
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* @see Set
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* @see TreeSet
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* @see SortedMap
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* @see Collection
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* @see Comparable
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* @see Comparator
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* @see ClassCastException
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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 interface SortedSet<E> extends Set<E>
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{
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/**
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* Returns the comparator used in sorting this set, or null if it is
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* the elements' natural ordering.
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*
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* @return the sorting comparator
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*/
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Comparator<? super E> comparator();
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/**
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* Returns the first (lowest sorted) element in the set.
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*
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* @return the first element
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* @throws NoSuchElementException if the set is empty.
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*/
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E first();
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/**
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* Returns a view of the portion of the set strictly less than toElement. The
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* view is backed by this set, so changes in one show up in the other.
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* The subset supports all optional operations of the original.
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* <p>
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*
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* The returned set throws an IllegalArgumentException any time an element is
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* used which is out of the range of toElement. Note that the endpoint, toElement,
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* is not included; if you want this value included, pass its successor object in to
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* toElement. For example, for Integers, you could request
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* <code>headSet(new Integer(limit.intValue() + 1))</code>.
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*
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* @param toElement the exclusive upper range of the subset
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* @return the subset
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* @throws ClassCastException if toElement is not comparable to the set
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* contents
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* @throws IllegalArgumentException if this is a subSet, and toElement is out
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* of range
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* @throws NullPointerException if toElement is null but the set does not
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* allow null elements
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*/
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SortedSet<E> headSet(E toElement);
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/**
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* Returns the last (highest sorted) element in the set.
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*
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* @return the last element
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* @throws NoSuchElementException if the set is empty.
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*/
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E last();
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/**
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* Returns a view of the portion of the set greater than or equal to
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* fromElement, and strictly less than toElement. The view is backed by
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* this set, so changes in one show up in the other. The subset supports all
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* optional operations of the original.
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* <p>
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*
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* The returned set throws an IllegalArgumentException any time an element is
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* used which is out of the range of fromElement and toElement. Note that the
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* lower endpoint is included, but the upper is not; if you want to
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* change the inclusion or exclusion of an endpoint, pass its successor
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* object in instead. For example, for Integers, you can request
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* <code>subSet(new Integer(lowlimit.intValue() + 1),
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* new Integer(highlimit.intValue() + 1))</code> to reverse
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* the inclusiveness of both endpoints.
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*
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* @param fromElement the inclusive lower range of the subset
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* @param toElement the exclusive upper range of the subset
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* @return the subset
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* @throws ClassCastException if fromElement or toElement is not comparable
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* to the set contents
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* @throws IllegalArgumentException if this is a subSet, and fromElement or
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* toElement is out of range
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* @throws NullPointerException if fromElement or toElement is null but the
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* set does not allow null elements
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*/
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SortedSet<E> subSet(E fromElement, E toElement);
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/**
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* Returns a view of the portion of the set greater than or equal to
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* fromElement. The view is backed by this set, so changes in one show up
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* in the other. The subset supports all optional operations of the original.
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* <p>
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*
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* The returned set throws an IllegalArgumentException any time an element is
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* used which is out of the range of fromElement. Note that the endpoint,
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* fromElement, is included; if you do not want this value to be included, pass its
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* successor object in to fromElement. For example, for Integers, you could request
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* <code>tailSet(new Integer(limit.intValue() + 1))</code>.
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*
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* @param fromElement the inclusive lower range of the subset
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* @return the subset
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* @throws ClassCastException if fromElement is not comparable to the set
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* contents
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* @throws IllegalArgumentException if this is a subSet, and fromElement is
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* out of range
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* @throws NullPointerException if fromElement is null but the set does not
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* allow null elements
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*/
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SortedSet<E> tailSet(E fromElement);
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}
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