com.sleepycat.collections
Class StoredValueSet

java.lang.Object
  |
  +--com.sleepycat.collections.StoredContainer
        |
        +--com.sleepycat.collections.StoredCollection
              |
              +--com.sleepycat.collections.StoredValueSet

All Implemented Interfaces:

Cloneable, Collection, Set

Direct Known Subclasses:

StoredSortedValueSet

public class StoredValueSet

extends StoredCollection

implements Set

The Set returned by Map.values() and Map.duplicates(), and which can also be constructed directly if a Map is not needed. Although this collection is a set it may contain duplicate values. Only if an entity value binding is used are all elements guaranteed to be unique.

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

• The size() method always throws UnsupportedOperationException because, for performance reasons, databases do not maintain their total record count.
• All iterators must be explicitly closed using StoredIterator.close() or StoredIterator.close(java.util.Iterator) to release the underlying database cursor resources.

Author:

Mark Hayes

Constructor Summary

StoredValueSet(Database database, EntityBinding valueEntityBinding, boolean writeAllowed)
Creates a value set entity view of a Database.

StoredValueSet(Database database, EntryBinding valueBinding, boolean writeAllowed)
Creates a value set view of a Database.

Method Summary

boolean	add(Object entity) Adds the specified entity to this set if it is not already present (optional operation).
boolean	contains(Object value) Returns true if this set contains the specified element.
boolean	remove(Object value) Removes the specified value from this set if it is present (optional operation).
int	size() Always throws UnsupportedOperationException.

Methods inherited from class com.sleepycat.collections.StoredCollection

addAll, containsAll, equals, iterator, iterator, join, removeAll, retainAll, toArray, toArray, toList, toString

Methods inherited from class com.sleepycat.collections.StoredContainer

areDuplicatesAllowed, areDuplicatesOrdered, areKeysRenumbered, clear, isDirtyRead, isDirtyReadAllowed, isEmpty, isOrdered, isSecondary, isTransactional, isWriteAllowed

Methods inherited from class java.lang.Object

getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Set

addAll, clear, containsAll, equals, hashCode, isEmpty, iterator, removeAll, retainAll, toArray, toArray

Constructor Detail

StoredValueSet

public StoredValueSet(Database database,
                      EntryBinding valueBinding,
                      boolean writeAllowed)

Creates a value set view of a Database.

Parameters:

database - is the Database underlying the new collection.

valueBinding - is the binding used to translate between value buffers and value 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.

StoredValueSet

public StoredValueSet(Database database,
                      EntityBinding valueEntityBinding,
                      boolean writeAllowed)

Creates a value set entity view of a Database.

Parameters:

database - is the Database underlying the new collection.

valueEntityBinding - is the binding used to translate between key/value buffers and entity value 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 entity)

Adds the specified entity to this set if it is not already present (optional operation). This method conforms to the Set.add(java.lang.Object) interface.

Specified by:

add in interface Set

Parameters:

entity - is the entity to be added.

Returns:

true if the entity was added, that is the key-value pair represented by the entity was not previously present in the collection.

Throws:

UnsupportedOperationException - if the collection is read-only, if the collection is indexed, or if an entity binding is not used.

RuntimeExceptionWrapper - if a DatabaseException is thrown.

contains

public boolean contains(Object value)

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

Specified by:

contains in interface Set

Parameters:

value - the value to check.

Returns:

whether the set contains the given value.

remove

public boolean remove(Object value)

Removes the specified value from this set if it is present (optional operation). If an entity binding is used, the key-value pair represented by the given entity is removed. If an entity binding is used, the first occurrence of a key-value pair with the given value is removed. 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.

size

public int size()

Description copied from class: StoredContainer

Always throws UnsupportedOperationException. The size of a database cannot be obtained reliably or inexpensively. This method therefore violates the Collection.size() and Map.size() interfaces.

Specified by:

size in interface Set

Overrides:

size in class StoredContainer

Returns:

always throws an exception.