/*- * See the file LICENSE for redistribution information. * * Copyright (c) 2000,2008 Oracle. All rights reserved. * * $Id: StoredSortedKeySet.java,v 12.8 2008/01/08 20:58:36 bostic Exp $ */ package com.sleepycat.collections; import java.util.Comparator; import java.util.SortedSet; import com.sleepycat.bind.EntryBinding; import com.sleepycat.db.Database; /** * The SortedSet returned by Map.keySet() and which can also be constructed * directly if a Map is not needed. * Since this collection is a set it only contains one element for each key, * even when duplicates are allowed. Key set iterators are therefore * particularly useful for enumerating the unique keys of a store or index that * allows duplicates. * * <p>In addition to the standard SortedSet methods, this class provides the * following methods for stored sorted sets only. Note that the use of these * methods is not compatible with the standard Java collections interface.</p> * <ul> * <li>{@link #headSet(Object, boolean)}</li> * <li>{@link #tailSet(Object, boolean)}</li> * <li>{@link #subSet(Object, boolean, Object, boolean)}</li> * </ul> * * @author Mark Hayes */ public class StoredSortedKeySet extends StoredKeySet implements SortedSet { /** * Creates a sorted key set view of a {@link Database}. * * @param database is the Database underlying the new collection. * * @param keyBinding is the binding used to translate between key buffers * and key objects. * * @param writeAllowed is true to create a read-write collection or false * to create a read-only collection. * * @throws IllegalArgumentException if formats are not consistently * defined or a parameter is invalid. * * @throws RuntimeExceptionWrapper if a {@link * com.sleepycat.db.DatabaseException} is thrown. */ public StoredSortedKeySet(Database database, EntryBinding keyBinding, boolean writeAllowed) { super(new DataView(database, keyBinding, null, null, writeAllowed, null)); } StoredSortedKeySet(DataView keySetView) { super(keySetView); } /** * Returns null since comparators are not supported. The natural ordering * of a stored collection is data byte order, whether the data classes * implement the {@link java.lang.Comparable} interface or not. * This method does not conform to the {@link SortedSet#comparator} * interface. * * @return null. */ public Comparator comparator() { return null; } /** * Returns the first (lowest) element currently in this sorted set. * This method conforms to the {@link SortedSet#first} interface. * * @return the first element. * * @throws RuntimeExceptionWrapper if a {@link * com.sleepycat.db.DatabaseException} is thrown. */ public Object first() { return getFirstOrLast(true); } /** * Returns the last (highest) element currently in this sorted set. * This method conforms to the {@link SortedSet#last} interface. * * @return the last element. * * @throws RuntimeExceptionWrapper if a {@link * com.sleepycat.db.DatabaseException} is thrown. */ public Object last() { return getFirstOrLast(false); } /** * Returns a view of the portion of this sorted set whose elements are * strictly less than toKey. * This method conforms to the {@link SortedSet#headSet} interface. * * <p>Note that the return value is a StoredCollection and must be treated * as such; for example, its iterators must be explicitly closed.</p> * * @param toKey is the upper bound. * * @return the subset. * * @throws RuntimeExceptionWrapper if a {@link * com.sleepycat.db.DatabaseException} is thrown. */ public SortedSet headSet(Object toKey) { return subSet(null, false, toKey, false); } /** * Returns a view of the portion of this sorted set whose elements are * strictly less than toKey, optionally including toKey. * This method does not exist in the standard {@link SortedSet} interface. * * <p>Note that the return value is a StoredCollection and must be treated * as such; for example, its iterators must be explicitly closed.</p> * * @param toKey is the upper bound. * * @param toInclusive is true to include toKey. * * @return the subset. * * @throws RuntimeExceptionWrapper if a {@link * com.sleepycat.db.DatabaseException} is thrown. */ public SortedSet headSet(Object toKey, boolean toInclusive) { return subSet(null, false, toKey, toInclusive); } /** * Returns a view of the portion of this sorted set whose elements are * greater than or equal to fromKey. * This method conforms to the {@link SortedSet#tailSet} interface. * * <p>Note that the return value is a StoredCollection and must be treated * as such; for example, its iterators must be explicitly closed.</p> * * @param fromKey is the lower bound. * * @return the subset. * * @throws RuntimeExceptionWrapper if a {@link * com.sleepycat.db.DatabaseException} is thrown. */ public SortedSet tailSet(Object fromKey) { return subSet(fromKey, true, null, false); } /** * Returns a view of the portion of this sorted set whose elements are * strictly greater than fromKey, optionally including fromKey. * This method does not exist in the standard {@link SortedSet} interface. * * <p>Note that the return value is a StoredCollection and must be treated * as such; for example, its iterators must be explicitly closed.</p> * * @param fromKey is the lower bound. * * @param fromInclusive is true to include fromKey. * * @return the subset. * * @throws RuntimeExceptionWrapper if a {@link * com.sleepycat.db.DatabaseException} is thrown. */ public SortedSet tailSet(Object fromKey, boolean fromInclusive) { return subSet(fromKey, fromInclusive, null, false); } /** * Returns a view of the portion of this sorted set whose elements range * from fromKey, inclusive, to toKey, exclusive. * This method conforms to the {@link SortedSet#subSet} interface. * * <p>Note that the return value is a StoredCollection and must be treated * as such; for example, its iterators must be explicitly closed.</p> * * @param fromKey is the lower bound. * * @param toKey is the upper bound. * * @return the subset. * * @throws RuntimeExceptionWrapper if a {@link * com.sleepycat.db.DatabaseException} is thrown. */ public SortedSet subSet(Object fromKey, Object toKey) { return subSet(fromKey, true, toKey, false); } /** * Returns a view of the portion of this sorted set whose elements are * strictly greater than fromKey and strictly less than toKey, * optionally including fromKey and toKey. * This method does not exist in the standard {@link SortedSet} interface. * * <p>Note that the return value is a StoredCollection and must be treated * as such; for example, its iterators must be explicitly closed.</p> * * @param fromKey is the lower bound. * * @param fromInclusive is true to include fromKey. * * @param toKey is the upper bound. * * @param toInclusive is true to include toKey. * * @return the subset. * * @throws RuntimeExceptionWrapper if a {@link * com.sleepycat.db.DatabaseException} is thrown. */ public SortedSet subSet(Object fromKey, boolean fromInclusive, Object toKey, boolean toInclusive) { try { return new StoredSortedKeySet( view.subView(fromKey, fromInclusive, toKey, toInclusive, null)); } catch (Exception e) { throw StoredContainer.convertException(e); } } }