org.hypergraphdb.indexing

Class HGValueIndexer<KeyType,ValueType>

java.lang.Object

org.hypergraphdb.indexing.HGValueIndexer<KeyType,ValueType>

All Implemented Interfaces:

HGIndexer<KeyType,ValueType>

Direct Known Subclasses:

TargetToTargetIndexer

public abstract class HGValueIndexer<KeyType,ValueType>
extends Object
implements HGIndexer<KeyType,ValueType>

An indexer that not only determines the key in an index entry, but the value as well. By default, HGKeyIndexer implementation provide a key by which to index HyperGraph atoms. In other words, atoms are the "default" values for index entries. A HGValueIndexer provides also the value in an index entry in cases where it is not the atom itself.

Author:

Borislav Iordanov

Constructor Summary

Constructors

Constructor and Description
HGValueIndexer()
HGValueIndexer(HGHandle type)
HGValueIndexer(String name, HGHandle type)

Method Summary

Methods

Modifier and Type	Method and Description
abstract KeyType	getKey(HyperGraph graph, Object atom) Returns an index key for the given atom.
String	getName()
HGHandle	getType() Return the handle of the atom type all of whose instances should be indexed by this indexer.
abstract ValueType	getValue(HyperGraph graph, Object atom) Return the value of an index entry based on the passed in atom.
abstract ByteArrayConverter<ValueType>	getValueConverter(HyperGraph graph) Return a ByteArrayConverter capable of converting index entry values to/from byte arrays.
void	index(HyperGraph graph, HGHandle atomHandle, Object atom, HGIndex<KeyType,ValueType> index) Add a particular atom the the index.
void	setName(String name)
void	setType(HGHandle type) Set the handle of the atom type all of whose instances should be indexed by this indexer.
void	unindex(HyperGraph graph, HGHandle atomHandle, Object atom, HGIndex<KeyType,ValueType> index) Remove a particular from the index, assuming it is currently being indexed.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.hypergraphdb.indexing.HGIndexer

equals, getComparator, getConverter, hashCode

Constructor Detail

HGValueIndexer

public HGValueIndexer()

HGValueIndexer

public HGValueIndexer(String name,
              HGHandle type)

HGValueIndexer

public HGValueIndexer(HGHandle type)

Method Detail

getName

public String getName()

setName

public void setName(String name)

getType

public HGHandle getType()

Description copied from interface: HGIndexer

Return the handle of the atom type all of whose instances should be indexed by this indexer.

Specified by:

getType in interface HGIndexer<KeyType,ValueType>

setType

public void setType(HGHandle type)

Description copied from interface: HGIndexer

Set the handle of the atom type all of whose instances should be indexed by this indexer.

Specified by:

setType in interface HGIndexer<KeyType,ValueType>

index

public void index(HyperGraph graph,
         HGHandle atomHandle,
         Object atom,
         HGIndex<KeyType,ValueType> index)

Description copied from interface: HGIndexer

Add a particular atom the the index. This method can safely assume that the atom hasn't been previously added to the index.

Specified by:

index in interface HGIndexer<KeyType,ValueType>

Parameters:

graph - The HyperGraph instance where the atom resides.

index - The storage index where the atom should be added.

unindex

public void unindex(HyperGraph graph,
           HGHandle atomHandle,
           Object atom,
           HGIndex<KeyType,ValueType> index)

Description copied from interface: HGIndexer

Remove a particular from the index, assuming it is currently being indexed.

Specified by:

unindex in interface HGIndexer<KeyType,ValueType>

Parameters:

graph - The HyperGraph instance where the atom resides.

index - The storage index from the atom should be removed.

getValue

public abstract ValueType getValue(HyperGraph graph,
                 Object atom)

Return the value of an index entry based on the passed in atom.

getKey

public abstract KeyType getKey(HyperGraph graph,
             Object atom)

Returns an index key for the given atom.

Parameters:

graph - The current HyperGraph instance.

atom - The atom being indexed.

Returns:

The index key. If the return value is not a byte[], a non-null ByteArrayConverter must be provided by the getConverter method.

getValueConverter

public abstract ByteArrayConverter<ValueType> getValueConverter(HyperGraph graph)

Return a ByteArrayConverter capable of converting index entry values to/from byte arrays.

Parameters:

graph -

Returns: