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Berkeley DB version 4.4.20 |
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java.lang.Object com.sleepycat.collections.StoredContainer com.sleepycat.collections.StoredCollection com.sleepycat.collections.StoredKeySet
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:
StoredContainer.size()
method always throws
UnsupportedOperationException
because, for performance reasons,
databases do not maintain their total record count.StoredIterator.close()
or StoredIterator.close(java.util.Iterator)
to release the underlying database cursor resources.
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 |
public StoredKeySet(Database database, EntryBinding keyBinding, boolean writeAllowed)
Database
.
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.
IllegalArgumentException
- if formats are not consistently
defined or a parameter is invalid.
RuntimeExceptionWrapper
- if a DatabaseException
is
thrown.Method Detail |
public boolean add(Object key)
Set.add(java.lang.Object)
interface.
add
in interface Set
UnsupportedOperationException
- if the collection is indexed, or
if the collection is read-only.
RuntimeExceptionWrapper
- if a DatabaseException
is
thrown.public boolean remove(Object key)
Set.remove(java.lang.Object)
interface.
remove
in interface Set
UnsupportedOperationException
- if the collection is read-only.
RuntimeExceptionWrapper
- if a DatabaseException
is
thrown.public boolean contains(Object key)
Set.contains(java.lang.Object)
interface.
contains
in interface Set
RuntimeExceptionWrapper
- if a DatabaseException
is
thrown.
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Berkeley DB version 4.4.20 |
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