org.apache.ignite.cache

Interface CacheInterceptor<K,V>

All Superinterfaces:

Serializable

All Known Implementing Classes:

CacheInterceptorAdapter

public interface CacheInterceptor<K,V>
extends Serializable

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 CacheConfiguration.getInterceptor() configuration property.

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

Method Summary

Modifier and Type	Method and Description
void	onAfterPut(javax.cache.Cache.Entry<K,V> entry) This method is called after new value has been stored.
void	onAfterRemove(javax.cache.Cache.Entry<K,V> entry) This method is called after value has been removed.
V	onBeforePut(javax.cache.Cache.Entry<K,V> entry, V newVal) This method is called within IgniteCache.put(Object, Object) and similar operations before new value is stored in cache.
@Nullable IgniteBiTuple<Boolean,V>	onBeforeRemove(javax.cache.Cache.Entry<K,V> entry) This method is called within IgniteCache.remove(Object) and similar operations to provide control over returned value.
V	onGet(K key, V val) This method is called within IgniteCache.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 IgniteCache.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:

Cache.get(Object)

onBeforePut

@Nullable
V onBeforePut(javax.cache.Cache.Entry<K,V> entry,
                        V newVal)

This method is called within IgniteCache.put(Object, Object) 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.

IMPORTANT: for this method to take affect, newVal and the returned value have to be different instances. I.e., you should not mutate newVal directly, but instead create a copy, update it and then return from the interceptor.

Parameters:

entry - Old entry. If CacheConfiguration.isCopyOnRead() is true, then is copy.

newVal - New value.

Returns:

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

See Also:

IgniteCache.put(Object, Object)

onAfterPut

void onAfterPut(javax.cache.Cache.Entry<K,V> entry)

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:

entry - Current entry. If CacheConfiguration.isCopyOnRead() is true then entry is a copy.

onBeforeRemove

@Nullable
@Nullable IgniteBiTuple<Boolean,V> onBeforeRemove(javax.cache.Cache.Entry<K,V> entry)

This method is called within IgniteCache.remove(Object) 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:

entry - Old entry. If CacheConfiguration.isCopyOnRead() is true then entry is a copy.

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:

IgniteCache.remove(Object)

onAfterRemove

void onAfterRemove(javax.cache.Cache.Entry<K,V> entry)

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:

entry - Removed entry. If CacheConfiguration.isCopyOnRead() is true then entry is a copy.