com.sleepycat.collections.StoredCollections Maven / Gradle / Ivy
/*-
* 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.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.SortedMap;
import java.util.SortedSet;
import com.sleepycat.je.CursorConfig;
/**
* Static methods operating on collections and maps.
*
* This class consists exclusively of static methods that operate on or
* return stored collections and maps, jointly called containers. It contains
* methods for changing certain properties of a container. Because container
* properties are immutable, these methods always return a new container
* instance. This allows stored container instances to be used safely by
* multiple threads. Creating the new container instance is not expensive and
* creates only two new objects.
*
* When a container is created with a particular property, all containers
* and iterators derived from that container will inherit the property. For
* example, if a read-uncommitted Map is created then calls to its subMap(),
* values(), entrySet(), and keySet() methods will create read-uncommitted
* containers also.
*
* Method names beginning with "configured" create a new container with a
* specified {@link CursorConfig} from a given stored container. This allows
* configuring a container for read-committed isolation, read-uncommitted
* isolation, or any other property supported by CursorConfig.
* All operations performed with the resulting container will be performed with
* the specified cursor configuration.
*/
public class StoredCollections {
private StoredCollections() {}
/**
* Creates a configured collection from a given stored collection.
*
* @param storedCollection the base collection.
*
* @param config is the cursor configuration to be used for all operations
* performed via the new collection instance; null may be specified to use
* the default configuration.
*
* @param the element class.
*
* @return the configured collection.
*
* @throws ClassCastException if the given container is not a
* StoredContainer.
*/
public static Collection configuredCollection(Collection
storedCollection,
CursorConfig config) {
return (Collection)
((StoredContainer) storedCollection).configuredClone(config);
}
/**
* Creates a configured list from a given stored list.
*
* Note that this method may not be called in the JE product, since the
* StoredList class is not supported.
*
* @param storedList the base list.
*
* @param config is the cursor configuration to be used for all operations
* performed via the new list instance; null may be specified to use the
* default configuration.
*
* @param the element class.
*
* @return the configured list.
*
* @throws ClassCastException if the given container is not a
* StoredContainer.
*/
public static List configuredList(List storedList,
CursorConfig config) {
return (List) ((StoredContainer) storedList).configuredClone(config);
}
/**
* Creates a configured map from a given stored map.
*
* @param storedMap the base map.
*
* @param config is the cursor configuration to be used for all operations
* performed via the new map instance; null may be specified to use the
* default configuration.
*
* @param the key class.
*
* @param the value class.
*
* @return the configured map.
*
* @throws ClassCastException if the given container is not a
* StoredContainer.
*/
public static Map configuredMap(Map storedMap,
CursorConfig config) {
return (Map) ((StoredContainer) storedMap).configuredClone(config);
}
/**
* Creates a configured set from a given stored set.
*
* @param storedSet the base set.
*
* @param config is the cursor configuration to be used for all operations
* performed via the new set instance; null may be specified to use the
* default configuration.
*
* @param the element class.
*
* @return the configured set.
*
* @throws ClassCastException if the given container is not a
* StoredContainer.
*/
public static Set configuredSet(Set storedSet,
CursorConfig config) {
return (Set) ((StoredContainer) storedSet).configuredClone(config);
}
/**
* Creates a configured sorted map from a given stored sorted map.
*
* @param storedSortedMap the base map.
*
* @param config is the cursor configuration to be used for all operations
* performed via the new map instance; null may be specified to use the
* default configuration.
*
* @param the key class.
*
* @param the value class.
*
* @return the configured map.
*
* @throws ClassCastException if the given container is not a
* StoredContainer.
*/
public static SortedMap configuredSortedMap
(SortedMap storedSortedMap, CursorConfig config) {
return (SortedMap)
((StoredContainer) storedSortedMap).configuredClone(config);
}
/**
* Creates a configured sorted set from a given stored sorted set.
*
* @param storedSortedSet the base set.
*
* @param config is the cursor configuration to be used for all operations
* performed via the new set instance; null may be specified to use the
* default configuration.
*
* @param the element class.
*
* @return the configured set.
*
* @throws ClassCastException if the given container is not a
* StoredContainer.
*/
public static SortedSet configuredSortedSet(SortedSet
storedSortedSet,
CursorConfig config) {
return (SortedSet)
((StoredContainer) storedSortedSet).configuredClone(config);
}
/**
* Clones an iterator preserving its current position.
*
* @param iter an iterator to clone.
*
* @param the element class.
*
* @return a new {@code Iterator} having the same position as the given
* iterator.
*
* @throws ClassCastException if the given iterator was not obtained via a
* {@link StoredCollection} method.
*/
public static Iterator iterator(Iterator iter) {
return ((BaseIterator) iter).dup();
}
}