org.apache.ignite.cache.eviction

Interface EvictionPolicy<K,V>

All Known Implementing Classes:

AbstractEvictionPolicy, FifoEvictionPolicy, IgfsPerBlockLruEvictionPolicy, LruEvictionPolicy, SortedEvictionPolicy

public interface EvictionPolicy<K,V>

Pluggable cache eviction policy. Usually, implementations will internally order cache entries based on onEntryAccessed(boolean, EvictableEntry) notifications and whenever an element needs to be evicted, EvictableEntry.evict() method should be called.

Ignite comes with following eviction policies out-of-the-box:

• LruEvictionPolicy
• FifoEvictionPolicy
• SortedEvictionPolicy

The eviction policy thread-safety is ensured by Ignition. Implementations of this interface should not worry about concurrency and should be implemented as they were only accessed from one thread.

Note that implementations of all eviction policies provided by Ignite are very light weight in a way that they are all lock-free (or very close to it), and do not create any internal tables, arrays, or other expensive structures. The eviction order is preserved by attaching light-weight meta-data to existing cache entries.

Method Summary

Modifier and Type	Method and Description
void	onEntryAccessed(boolean rmv, EvictableEntry<K,V> entry) Callback for whenever entry is accessed.

Method Detail

onEntryAccessed

void onEntryAccessed(boolean rmv,
                     EvictableEntry<K,V> entry)

Callback for whenever entry is accessed.

Parameters:

rmv - True if entry has been removed, false otherwise.

entry - Accessed entry.