org.gridgain.grid.cache.affinity

Class GridCacheAffinityKey<K>

java.lang.Object

org.gridgain.grid.cache.affinity.GridCacheAffinityKey<K>

All Implemented Interfaces:

Externalizable, Serializable

public class GridCacheAffinityKey<K>
extends Object
implements Externalizable

Optional wrapper for cache keys to provide support for custom affinity mapping. The value returned by affinityKey(Object) method will be used for key-to-node affinity.

Note that the equals(Object) and hashCode() methods delegate directly to the wrapped cache key provided by key() method.

This class is optional and does not have to be used. It only provides extra convenience whenever custom affinity mapping is required. Here is an example of how Person objects can be collocated with Company objects they belong to:

 Object personKey = new GridCacheAffinityKey(myPersonId, myCompanyId);

 // Both, the company and the person objects will be cached on the same node.
 cache.put(myCompanyId, new Company(..));
 cache.put(personKey, new Person(..));
 

For more information and examples of cache affinity refer to GridCacheAffinityKeyMapper and @GridCacheAffinityKeyMapped documentation.

See Also:

GridCacheAffinityKeyMapped, GridCacheAffinityKeyMapper, GridCacheAffinityFunction, Serialized Form

Constructor Summary

Constructors

Constructor and Description
GridCacheAffinityKey() Empty constructor.
GridCacheAffinityKey(K key) Initializes key wrapper for a given key.
GridCacheAffinityKey(K key, Object affKey) Initializes key together with its affinity key counter-part.

Method Summary

Methods

Modifier and Type	Method and Description
<T> T	affinityKey() Gets affinity key to use for affinity mapping.
void	affinityKey(Object affKey) Sets affinity key to use for affinity mapping.
boolean	equals(Object obj) Equality check which delegates to the underlying key equality.
int	hashCode() Hash code implementation which delegates to the underlying key().
K	key() Gets wrapped key.
void	key(K key) Sets wrapped key.
void	readExternal(ObjectInput in)
String	toString()
void	writeExternal(ObjectOutput out)

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

GridCacheAffinityKey

public GridCacheAffinityKey()

Empty constructor.

GridCacheAffinityKey

public GridCacheAffinityKey(K key)

Initializes key wrapper for a given key. If affinity key is not initialized, then this key will be used for affinity.

Parameters:

key - Key.

GridCacheAffinityKey

public GridCacheAffinityKey(K key,
                    Object affKey)

Initializes key together with its affinity key counter-part.

Parameters:

key - Key.

affKey - Affinity key.

Method Detail

key

public K key()

Gets wrapped key.

Returns:

Wrapped key.

key

public void key(K key)

Sets wrapped key.

Parameters:

key - Wrapped key.

affinityKey

@GridCacheAffinityKeyMapped
public <T> T affinityKey()

Gets affinity key to use for affinity mapping. If affinity key is not provided, then key value will be returned.

This method is annotated with GridCacheAffinityKeyMapped and will be picked up by GridCacheDefaultAffinityKeyMapper automatically.

Returns:

Affinity key to use for affinity mapping.

affinityKey

public void affinityKey(Object affKey)

Sets affinity key to use for affinity mapping. If affinity key is not provided, then key value will be returned.

Parameters:

affKey - Affinity key to use for affinity mapping.

writeExternal

public void writeExternal(ObjectOutput out)
                   throws IOException

Specified by:

writeExternal in interface Externalizable

Throws:

IOException

readExternal

public void readExternal(ObjectInput in)
                  throws IOException,
                         ClassNotFoundException

Specified by:

readExternal in interface Externalizable

Throws:

IOException

ClassNotFoundException

hashCode

public int hashCode()

Hash code implementation which delegates to the underlying key(). Note, however, that different subclasses of GridCacheAffinityKey will produce different hash codes.

Users should override this method if different behavior is desired.

Overrides:

hashCode in class Object

Returns:

Hash code.

equals

public boolean equals(Object obj)

Equality check which delegates to the underlying key equality. Note, however, that different subclasses of GridCacheAffinityKey will never be equal.

Users should override this method if different behavior is desired.

Overrides:

equals in class Object

Parameters:

obj - Object to check for equality.

Returns:

True if objects are equal.

toString

public String toString()

Overrides:

toString in class Object