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Berkeley DB
version 4.4.20

com.sleepycat.collections
Class StoredKeySet

java.lang.Object
  extended bycom.sleepycat.collections.StoredContainer
      extended bycom.sleepycat.collections.StoredCollection
          extended bycom.sleepycat.collections.StoredKeySet
All Implemented Interfaces:
Cloneable, Collection, Set
Direct Known Subclasses:
StoredSortedKeySet

public class StoredKeySet
extends StoredCollection
implements Set

The Set 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.

Note that this class does not conform to the standard Java collections interface in the following ways:


Constructor Summary
StoredKeySet(Database database, EntryBinding keyBinding, boolean writeAllowed)
          Creates a key set view of a Database.
 
Method Summary
 boolean add(Object key)
          Adds the specified key to this set if it is not already present (optional operation).
 boolean contains(Object key)
          Returns true if this set contains the specified key.
 boolean remove(Object key)
          Removes the specified key from this set if it is present (optional operation).
 
Methods inherited from class com.sleepycat.collections.StoredCollection
addAll, containsAll, equals, hashCode, iterator, iterator, join, removeAll, retainAll, toArray, toArray, toList, toString
 
Methods inherited from class com.sleepycat.collections.StoredContainer
areDuplicatesAllowed, areDuplicatesOrdered, areKeysRenumbered, clear, getCursorConfig, isDirtyRead, isDirtyReadAllowed, isEmpty, isOrdered, isSecondary, isTransactional, isWriteAllowed, size
 
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface java.util.Set
addAll, clear, containsAll, equals, hashCode, isEmpty, iterator, removeAll, retainAll, size, toArray, toArray
 

Constructor Detail

StoredKeySet

public StoredKeySet(Database database,
                    EntryBinding keyBinding,
                    boolean writeAllowed)
Creates a key set view of a Database.

Parameters:
database - is the Database underlying the new collection.
keyBinding - is the binding used to translate between key buffers and key objects.
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.
RuntimeExceptionWrapper - if a DatabaseException is thrown.
Method Detail

add

public boolean add(Object key)
Adds the specified key to this set if it is not already present (optional operation). When a key is added the value in the underlying data store will be empty. This method conforms to the Set.add(java.lang.Object) interface.

Specified by:
add in interface Set
Throws:
UnsupportedOperationException - if the collection is indexed, or if the collection is read-only.
RuntimeExceptionWrapper - if a DatabaseException is thrown.

remove

public boolean remove(Object key)
Removes the specified key from this set if it is present (optional operation). If duplicates are allowed, this method removes all duplicates for the given key. This method conforms to the Set.remove(java.lang.Object) interface.

Specified by:
remove in interface Set
Throws:
UnsupportedOperationException - if the collection is read-only.
RuntimeExceptionWrapper - if a DatabaseException is thrown.

contains

public boolean contains(Object key)
Returns true if this set contains the specified key. This method conforms to the Set.contains(java.lang.Object) interface.

Specified by:
contains in interface Set
Throws:
RuntimeExceptionWrapper - if a DatabaseException is thrown.

Berkeley DB
version 4.4.20

Copyright (c) 1996-2005 Sleepycat Software, Inc. - All rights reserved.