com.espertech.esper.epl.db
Interface DataCache

All Known Implementing Classes:

DataCacheClearableMap, DataCacheExpiringImpl, DataCacheLRUImpl, DataCacheNullImpl

public interface DataCache

Implementations serve as caches for historical or reference data retrieved via lookup keys consisting or one or more rows represented by a list of events.

Method Summary

EventTable[]	getCached(java.lang.Object[] lookupKeys) Ask the cache if the keyed value is cached, returning a list or rows if the key is in the cache, or returning null to indicate no such key cached.
boolean	isActive() Returns true if the cache is active and currently caching, or false if the cache is inactive and not currently caching
void	put(java.lang.Object[] lookupKeys, EventTable[] rows) Puts into the cache a key and a list of rows, or an empty list if zero rows.

Method Detail

getCached

EventTable[] getCached(java.lang.Object[] lookupKeys)

Ask the cache if the keyed value is cached, returning a list or rows if the key is in the cache, or returning null to indicate no such key cached. Zero rows may also be cached.

Parameters:

lookupKeys - is the keys to look up in the cache

Returns:

a list of rows that can be empty is the key was found in the cache, or null if the key is not found in the cache

put

void put(java.lang.Object[] lookupKeys,
         EventTable[] rows)

Puts into the cache a key and a list of rows, or an empty list if zero rows.

The put method is designed to be called when the cache does not contain a key as determined by the get method. Implementations typically simply overwrite any keys put into the cache that already existed in the cache.

Parameters:

lookupKeys - is the keys to the cache entry

rows - is a number of rows

isActive

boolean isActive()

Returns true if the cache is active and currently caching, or false if the cache is inactive and not currently caching

Returns:

true for caching enabled, false for no caching taking place