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/*-
* Copyright (C) 2002, 2018, Oracle and/or its affiliates. All rights reserved.
*
* This file was distributed by Oracle as part of a version of Oracle Berkeley
* DB Java Edition made available at:
*
* http://www.oracle.com/technetwork/database/database-technologies/berkeleydb/downloads/index.html
*
* Please see the LICENSE file included in the top-level directory of the
* appropriate version of Oracle Berkeley DB Java Edition for a copy of the
* license and additional information.
*/
package com.sleepycat.collections;
import java.util.Comparator;
import java.util.SortedSet;
import com.sleepycat.bind.EntryBinding;
import com.sleepycat.je.Database;
/* */
import com.sleepycat.je.EnvironmentFailureException; // for javadoc
import com.sleepycat.je.OperationFailureException; // for javadoc
/* */
import com.sleepycat.util.RuntimeExceptionWrapper;
/**
* 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.
*
* 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.
*
* - {@link #headSet(Object, boolean)}
* - {@link #tailSet(Object, boolean)}
* - {@link #subSet(Object, boolean, Object, boolean)}
*
*
* @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 checked exception is thrown,
* including a {@code DatabaseException} on BDB (C edition).
*/
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 OperationFailureException if one of the Read Operation
* Failures occurs.
*
* @throws EnvironmentFailureException if an unexpected, internal or
* environment-wide failure occurs.
*
*
* @throws RuntimeExceptionWrapper if a checked exception is thrown,
* including a {@code DatabaseException} on BDB (C edition).
*/
public K 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 OperationFailureException if one of the Read Operation
* Failures occurs.
*
* @throws EnvironmentFailureException if an unexpected, internal or
* environment-wide failure occurs.
*
*
* @throws RuntimeExceptionWrapper if a checked exception is thrown,
* including a {@code DatabaseException} on BDB (C edition).
*/
public K 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.
*
* Note that the return value is a StoredCollection and must be treated
* as such; for example, its iterators must be explicitly closed.
*
* @param toKey is the upper bound.
*
* @return the subset.
*
* @throws RuntimeExceptionWrapper if a checked exception is thrown,
* including a {@code DatabaseException} on BDB (C edition).
*/
public SortedSet headSet(K 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.
*
* Note that the return value is a StoredCollection and must be treated
* as such; for example, its iterators must be explicitly closed.
*
* @param toKey is the upper bound.
*
* @param toInclusive is true to include toKey.
*
* @return the subset.
*
* @throws RuntimeExceptionWrapper if a checked exception is thrown,
* including a {@code DatabaseException} on BDB (C edition).
*/
public SortedSet headSet(K 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.
*
* Note that the return value is a StoredCollection and must be treated
* as such; for example, its iterators must be explicitly closed.
*
* @param fromKey is the lower bound.
*
* @return the subset.
*
* @throws RuntimeExceptionWrapper if a checked exception is thrown,
* including a {@code DatabaseException} on BDB (C edition).
*/
public SortedSet tailSet(K 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.
*
* Note that the return value is a StoredCollection and must be treated
* as such; for example, its iterators must be explicitly closed.
*
* @param fromKey is the lower bound.
*
* @param fromInclusive is true to include fromKey.
*
* @return the subset.
*
* @throws RuntimeExceptionWrapper if a checked exception is thrown,
* including a {@code DatabaseException} on BDB (C edition).
*/
public SortedSet tailSet(K 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.
*
* Note that the return value is a StoredCollection and must be treated
* as such; for example, its iterators must be explicitly closed.
*
* @param fromKey is the lower bound.
*
* @param toKey is the upper bound.
*
* @return the subset.
*
* @throws RuntimeExceptionWrapper if a checked exception is thrown,
* including a {@code DatabaseException} on BDB (C edition).
*/
public SortedSet subSet(K fromKey, K 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.
*
* Note that the return value is a StoredCollection and must be treated
* as such; for example, its iterators must be explicitly closed.
*
* @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 checked exception is thrown,
* including a {@code DatabaseException} on BDB (C edition).
*/
public SortedSet subSet(K fromKey,
boolean fromInclusive,
K toKey,
boolean toInclusive) {
try {
return new StoredSortedKeySet(
view.subView(fromKey, fromInclusive, toKey, toInclusive, null));
} catch (Exception e) {
throw StoredContainer.convertException(e);
}
}
}
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