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1: /* SortedSet.java -- A set that makes guarantees about the order of its 2: elements 3: Copyright (C) 1998, 2001, 2004, 2005 Free Software Foundation, Inc. 4: 5: This file is part of GNU Classpath. 6: 7: GNU Classpath is free software; you can redistribute it and/or modify 8: it under the terms of the GNU General Public License as published by 9: the Free Software Foundation; either version 2, or (at your option) 10: any later version. 11: 12: GNU Classpath is distributed in the hope that it will be useful, but 13: WITHOUT ANY WARRANTY; without even the implied warranty of 14: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15: General Public License for more details. 16: 17: You should have received a copy of the GNU General Public License 18: along with GNU Classpath; see the file COPYING. If not, write to the 19: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 20: 02110-1301 USA. 21: 22: Linking this library statically or dynamically with other modules is 23: making a combined work based on this library. Thus, the terms and 24: conditions of the GNU General Public License cover the whole 25: combination. 26: 27: As a special exception, the copyright holders of this library give you 28: permission to link this library with independent modules to produce an 29: executable, regardless of the license terms of these independent 30: modules, and to copy and distribute the resulting executable under 31: terms of your choice, provided that you also meet, for each linked 32: independent module, the terms and conditions of the license of that 33: module. An independent module is a module which is not derived from 34: or based on this library. If you modify this library, you may extend 35: this exception to your version of the library, but you are not 36: obligated to do so. If you do not wish to do so, delete this 37: exception statement from your version. */ 38: 39: 40: package java.util; 41: 42: /** 43: * A set which guarantees its iteration order. The elements in the set 44: * are related by the <i>natural ordering</i> if they are Comparable, or 45: * by the provided Comparator. Additional operations take advantage of 46: * the sorted nature of the set. 47: * <p> 48: * 49: * All elements entered in the set must be mutually comparable; in other words, 50: * <code>k1.compareTo(k2)</code> or <code>comparator.compare(k1, k2)</code> 51: * must not throw a ClassCastException. The ordering must be <i>consistent 52: * with equals</i> (see {@link Comparator} for this definition), if the 53: * set is to obey the general contract of the Set interface. If not, 54: * the results are well-defined, but probably not what you wanted. 55: * <p> 56: * 57: * It is recommended that all implementing classes provide four constructors: 58: * 1) one that takes no arguments and builds an empty set sorted by natural 59: * order of the elements; 2) one that takes a Comparator for the sorting order; 60: * 3) one that takes a Set and sorts according to the natural order of its 61: * elements; and 4) one that takes a SortedSet and sorts by the same 62: * comparator. Unfortunately, the Java language does not provide a way to 63: * enforce this. 64: * 65: * @author Original author unknown 66: * @author Eric Blake (ebb9@email.byu.edu) 67: * @see Set 68: * @see TreeSet 69: * @see SortedMap 70: * @see Collection 71: * @see Comparable 72: * @see Comparator 73: * @see ClassCastException 74: * @since 1.2 75: * @status updated to 1.4 76: */ 77: public interface SortedSet<E> extends Set<E> 78: { 79: /** 80: * Returns the comparator used in sorting this set, or null if it is 81: * the elements' natural ordering. 82: * 83: * @return the sorting comparator 84: */ 85: Comparator<? super E> comparator(); 86: 87: /** 88: * Returns the first (lowest sorted) element in the set. 89: * 90: * @return the first element 91: * @throws NoSuchElementException if the set is empty. 92: */ 93: E first(); 94: 95: /** 96: * Returns a view of the portion of the set strictly less than toElement. The 97: * view is backed by this set, so changes in one show up in the other. 98: * The subset supports all optional operations of the original. 99: * <p> 100: * 101: * The returned set throws an IllegalArgumentException any time an element is 102: * used which is out of the range of toElement. Note that the endpoint, toElement, 103: * is not included; if you want this value included, pass its successor object in to 104: * toElement. For example, for Integers, you could request 105: * <code>headSet(new Integer(limit.intValue() + 1))</code>. 106: * 107: * @param toElement the exclusive upper range of the subset 108: * @return the subset 109: * @throws ClassCastException if toElement is not comparable to the set 110: * contents 111: * @throws IllegalArgumentException if this is a subSet, and toElement is out 112: * of range 113: * @throws NullPointerException if toElement is null but the set does not 114: * allow null elements 115: */ 116: SortedSet<E> headSet(E toElement); 117: 118: /** 119: * Returns the last (highest sorted) element in the set. 120: * 121: * @return the last element 122: * @throws NoSuchElementException if the set is empty. 123: */ 124: E last(); 125: 126: /** 127: * Returns a view of the portion of the set greater than or equal to 128: * fromElement, and strictly less than toElement. The view is backed by 129: * this set, so changes in one show up in the other. The subset supports all 130: * optional operations of the original. 131: * <p> 132: * 133: * The returned set throws an IllegalArgumentException any time an element is 134: * used which is out of the range of fromElement and toElement. Note that the 135: * lower endpoint is included, but the upper is not; if you want to 136: * change the inclusion or exclusion of an endpoint, pass its successor 137: * object in instead. For example, for Integers, you can request 138: * <code>subSet(new Integer(lowlimit.intValue() + 1), 139: * new Integer(highlimit.intValue() + 1))</code> to reverse 140: * the inclusiveness of both endpoints. 141: * 142: * @param fromElement the inclusive lower range of the subset 143: * @param toElement the exclusive upper range of the subset 144: * @return the subset 145: * @throws ClassCastException if fromElement or toElement is not comparable 146: * to the set contents 147: * @throws IllegalArgumentException if this is a subSet, and fromElement or 148: * toElement is out of range 149: * @throws NullPointerException if fromElement or toElement is null but the 150: * set does not allow null elements 151: */ 152: SortedSet<E> subSet(E fromElement, E toElement); 153: 154: /** 155: * Returns a view of the portion of the set greater than or equal to 156: * fromElement. The view is backed by this set, so changes in one show up 157: * in the other. The subset supports all optional operations of the original. 158: * <p> 159: * 160: * The returned set throws an IllegalArgumentException any time an element is 161: * used which is out of the range of fromElement. Note that the endpoint, 162: * fromElement, is included; if you do not want this value to be included, pass its 163: * successor object in to fromElement. For example, for Integers, you could request 164: * <code>tailSet(new Integer(limit.intValue() + 1))</code>. 165: * 166: * @param fromElement the inclusive lower range of the subset 167: * @return the subset 168: * @throws ClassCastException if fromElement is not comparable to the set 169: * contents 170: * @throws IllegalArgumentException if this is a subSet, and fromElement is 171: * out of range 172: * @throws NullPointerException if fromElement is null but the set does not 173: * allow null elements 174: */ 175: SortedSet<E> tailSet(E fromElement); 176: }