1/*- 2 * See the file LICENSE for redistribution information. 3 * 4 * Copyright (c) 2000,2008 Oracle. All rights reserved. 5 * 6 * $Id: StoredSortedValueSet.java,v 12.8 2008/01/08 20:58:36 bostic Exp $ 7 */ 8 9package com.sleepycat.collections; 10 11import java.util.Comparator; 12import java.util.SortedSet; 13 14import com.sleepycat.bind.EntityBinding; 15import com.sleepycat.db.Database; 16 17/** 18 * The SortedSet returned by Map.values() and which can also be constructed 19 * directly if a Map is not needed. 20 * Although this collection is a set it may contain duplicate values. Only if 21 * an entity value binding is used are all elements guaranteed to be unique. 22 * 23 * <p>In addition to the standard SortedSet methods, this class provides the 24 * following methods for stored sorted value sets only. Note that the use of 25 * these methods is not compatible with the standard Java collections 26 * interface.</p> 27 * <ul> 28 * <li>{@link #headSet(Object, boolean)}</li> 29 * <li>{@link #tailSet(Object, boolean)}</li> 30 * <li>{@link #subSet(Object, boolean, Object, boolean)}</li> 31 * </ul> 32 * 33 * @author Mark Hayes 34 */ 35public class StoredSortedValueSet extends StoredValueSet implements SortedSet { 36 37 /* 38 * No valueBinding ctor is possible since key cannot be derived. 39 */ 40 41 /** 42 * Creates a sorted value set entity view of a {@link Database}. 43 * 44 * @param database is the Database underlying the new collection. 45 * 46 * @param valueEntityBinding is the binding used to translate between 47 * key/value buffers and entity value objects. 48 * 49 * @param writeAllowed is true to create a read-write collection or false 50 * to create a read-only collection. 51 * 52 * @throws IllegalArgumentException if formats are not consistently 53 * defined or a parameter is invalid. 54 * 55 * @throws RuntimeExceptionWrapper if a {@link 56 * com.sleepycat.db.DatabaseException} is thrown. 57 */ 58 public StoredSortedValueSet(Database database, 59 EntityBinding valueEntityBinding, 60 boolean writeAllowed) { 61 62 super(new DataView(database, null, null, valueEntityBinding, 63 writeAllowed, null)); 64 checkKeyDerivation(); 65 } 66 67 StoredSortedValueSet(DataView valueSetView) { 68 69 super(valueSetView); 70 checkKeyDerivation(); 71 } 72 73 private void checkKeyDerivation() { 74 75 if (!view.canDeriveKeyFromValue()) { 76 throw new IllegalArgumentException("Cannot derive key from value"); 77 } 78 } 79 80 /** 81 * Returns null since comparators are not supported. The natural ordering 82 * of a stored collection is data byte order, whether the data classes 83 * implement the {@link java.lang.Comparable} interface or not. 84 * This method does not conform to the {@link SortedSet#comparator} 85 * interface. 86 * 87 * @return null. 88 */ 89 public Comparator comparator() { 90 91 return null; 92 } 93 94 /** 95 * Returns the first (lowest) element currently in this sorted set. 96 * This method conforms to the {@link SortedSet#first} interface. 97 * 98 * @return the first element. 99 * 100 * @throws RuntimeExceptionWrapper if a {@link 101 * com.sleepycat.db.DatabaseException} is thrown. 102 */ 103 public Object first() { 104 105 return getFirstOrLast(true); 106 } 107 108 /** 109 * Returns the last (highest) element currently in this sorted set. 110 * This method conforms to the {@link SortedSet#last} interface. 111 * 112 * @return the last element. 113 * 114 * @throws RuntimeExceptionWrapper if a {@link 115 * com.sleepycat.db.DatabaseException} is thrown. 116 */ 117 public Object last() { 118 119 return getFirstOrLast(false); 120 } 121 122 /** 123 * Returns a view of the portion of this sorted set whose elements are 124 * strictly less than toValue. 125 * This method conforms to the {@link SortedSet#headSet} interface. 126 * 127 * <p>Note that the return value is a StoredCollection and must be treated 128 * as such; for example, its iterators must be explicitly closed.</p> 129 * 130 * @param toValue the upper bound. 131 * 132 * @return the subset. 133 * 134 * @throws RuntimeExceptionWrapper if a {@link 135 * com.sleepycat.db.DatabaseException} is thrown. 136 */ 137 public SortedSet headSet(Object toValue) { 138 139 return subSet(null, false, toValue, false); 140 } 141 142 /** 143 * Returns a view of the portion of this sorted set whose elements are 144 * strictly less than toValue, optionally including toValue. 145 * This method does not exist in the standard {@link SortedSet} interface. 146 * 147 * <p>Note that the return value is a StoredCollection and must be treated 148 * as such; for example, its iterators must be explicitly closed.</p> 149 * 150 * @param toValue is the upper bound. 151 * 152 * @param toInclusive is true to include toValue. 153 * 154 * @return the subset. 155 * 156 * @throws RuntimeExceptionWrapper if a {@link 157 * com.sleepycat.db.DatabaseException} is thrown. 158 */ 159 public SortedSet headSet(Object toValue, boolean toInclusive) { 160 161 return subSet(null, false, toValue, toInclusive); 162 } 163 164 /** 165 * Returns a view of the portion of this sorted set whose elements are 166 * greater than or equal to fromValue. 167 * This method conforms to the {@link SortedSet#tailSet} interface. 168 * 169 * <p>Note that the return value is a StoredCollection and must be treated 170 * as such; for example, its iterators must be explicitly closed.</p> 171 * 172 * @param fromValue is the lower bound. 173 * 174 * @return the subset. 175 * 176 * @throws RuntimeExceptionWrapper if a {@link 177 * com.sleepycat.db.DatabaseException} is thrown. 178 */ 179 public SortedSet tailSet(Object fromValue) { 180 181 return subSet(fromValue, true, null, false); 182 } 183 184 /** 185 * Returns a view of the portion of this sorted set whose elements are 186 * strictly greater than fromValue, optionally including fromValue. 187 * This method does not exist in the standard {@link SortedSet} interface. 188 * 189 * <p>Note that the return value is a StoredCollection and must be treated 190 * as such; for example, its iterators must be explicitly closed.</p> 191 * 192 * @param fromValue is the lower bound. 193 * 194 * @param fromInclusive is true to include fromValue. 195 * 196 * @return the subset. 197 * 198 * @throws RuntimeExceptionWrapper if a {@link 199 * com.sleepycat.db.DatabaseException} is thrown. 200 */ 201 public SortedSet tailSet(Object fromValue, boolean fromInclusive) { 202 203 return subSet(fromValue, fromInclusive, null, false); 204 } 205 206 /** 207 * Returns a view of the portion of this sorted set whose elements range 208 * from fromValue, inclusive, to toValue, exclusive. 209 * This method conforms to the {@link SortedSet#subSet} interface. 210 * 211 * <p>Note that the return value is a StoredCollection and must be treated 212 * as such; for example, its iterators must be explicitly closed.</p> 213 * 214 * @param fromValue is the lower bound. 215 * 216 * @param toValue is the upper bound. 217 * 218 * @return the subset. 219 * 220 * @throws RuntimeExceptionWrapper if a {@link 221 * com.sleepycat.db.DatabaseException} is thrown. 222 */ 223 public SortedSet subSet(Object fromValue, Object toValue) { 224 225 return subSet(fromValue, true, toValue, false); 226 } 227 228 /** 229 * Returns a view of the portion of this sorted set whose elements are 230 * strictly greater than fromValue and strictly less than toValue, 231 * optionally including fromValue and toValue. 232 * This method does not exist in the standard {@link SortedSet} interface. 233 * 234 * <p>Note that the return value is a StoredCollection and must be treated 235 * as such; for example, its iterators must be explicitly closed.</p> 236 * 237 * @param fromValue is the lower bound. 238 * 239 * @param fromInclusive is true to include fromValue. 240 * 241 * @param toValue is the upper bound. 242 * 243 * @param toInclusive is true to include toValue. 244 * 245 * @return the subset. 246 * 247 * @throws RuntimeExceptionWrapper if a {@link 248 * com.sleepycat.db.DatabaseException} is thrown. 249 */ 250 public SortedSet subSet(Object fromValue, boolean fromInclusive, 251 Object toValue, boolean toInclusive) { 252 253 try { 254 return new StoredSortedValueSet( 255 view.subView(fromValue, fromInclusive, toValue, toInclusive, 256 null)); 257 } catch (Exception e) { 258 throw StoredContainer.convertException(e); 259 } 260 } 261} 262