org.gridgain.grid.cache

Interface GridCacheInterceptor<K,V>

All Known Implementing Classes:

GridCacheInterceptorAdapter

public interface GridCacheInterceptor<K,V>

Cache interceptor. Cache interceptor can be used for getting callbacks before and after cache get(...), put(...), and remove(...) operations. The onBefore callbacks can also be used to change the values stored in cache or preventing entries from being removed from cache.

Cache interceptor is configured via GridCacheConfiguration.getInterceptor() configuration property.

Any grid resource from org.gridgain.grid.resources package can be injected into implementation of this interface.

Method Summary

Methods

Modifier and Type	Method and Description
void	onAfterPut(K key, V val) This method is called after new value has been stored.
void	onAfterRemove(K key, V val) This method is called after value has been removed.
V	onBeforePut(K key, V oldVal, V newVal) This method is called within GridCacheProjection.put(Object, Object, GridPredicate[]) and similar operations before new value is stored in cache.
GridBiTuple<Boolean,V>	onBeforeRemove(K key, V val) This method is called within GridCacheProjection.remove(Object, GridPredicate[]) and similar operations to provide control over returned value.
V	onGet(K key, V val) This method is called within GridCacheProjection.get(Object) and similar operations to provide control over returned value.

Method Detail

onGet

@Nullable
V onGet(K key,
               @Nullable
               V val)

This method is called within GridCacheProjection.get(Object) and similar operations to provide control over returned value.

If this method returns null, then get() operation results in null as well.

This method should not throw any exception.

Parameters:

key - Key.

val - Value mapped to key at the moment of get() operation.

Returns:

The new value to be returned as result of get() operation.

See Also:

GridCacheProjection.get(Object)

onBeforePut

@Nullable
V onBeforePut(K key,
                     @Nullable
                     V oldVal,
                     V newVal)

This method is called within GridCacheProjection.put(Object, Object, GridPredicate[]) and similar operations before new value is stored in cache.

Implementations should not execute any complex logic, including locking, networking or cache operations, as it may lead to deadlock, since this method is called from sensitive synchronization blocks.

This method should not throw any exception.

Parameters:

key - Key.

oldVal - Old value.

newVal - New value.

Returns:

Value to be put to cache. Returning null cancels the update.

See Also:

GridCacheProjection.put(Object, Object, GridPredicate[])

onAfterPut

void onAfterPut(K key,
              V val)

This method is called after new value has been stored.

Implementations should not execute any complex logic, including locking, networking or cache operations, as it may lead to deadlock, since this method is called from sensitive synchronization blocks.

This method should not throw any exception.

Parameters:

key - Key.

val - Current value.

onBeforeRemove

@Nullable
GridBiTuple<Boolean,V> onBeforeRemove(K key,
                                             @Nullable
                                             V val)

This method is called within GridCacheProjection.remove(Object, GridPredicate[]) and similar operations to provide control over returned value.

Implementations should not execute any complex logic, including locking, networking or cache operations, as it may lead to deadlock, since this method is called from sensitive synchronization blocks.

This method should not throw any exception.

Parameters:

key - Key.

val - Old value.

Returns:

Tuple. The first value is the flag whether remove should be cancelled or not. The second is the value to be returned as result of remove() operation, may be null.

See Also:

GridCacheProjection.remove(Object, GridPredicate[])

onAfterRemove

void onAfterRemove(K key,
                 V val)

This method is called after value has been removed.

Implementations should not execute any complex logic, including locking, networking or cache operations, as it may lead to deadlock, since this method is called from sensitive synchronization blocks.

This method should not throw any exception.

Parameters:

key - Key.

val - Removed value.