/*
* Copyright (c) 2008-2017, Hazelcast, Inc. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.hazelcast.map.impl.event;
import com.hazelcast.core.EntryEventType;
import com.hazelcast.nio.serialization.Data;
import com.hazelcast.spi.EventFilter;
/**
* A filtering strategy determines whether an event must be published based on a specific filter
* and if so, may alter the type of event that should be published.
*
* @see AbstractFilteringStrategy
* @see DefaultEntryEventFilteringStrategy
* @see QueryCacheNaturalFilteringStrategy
*/
public interface FilteringStrategy {
/**
* Used as return value from {@link #doFilter(EventFilter, Data, Object, Object, EntryEventType, String)}
* to indicate that an event registration's filter does not match.
*/
int FILTER_DOES_NOT_MATCH = -1;
/**
* Main entry point for filtering events according to given filter.
*
* @param filter the event filter
* @param dataKey the event entry key
* @param dataOldValue the old value of the event entry
* @param dataValue the new value of the event entry
* @param eventType the event type
* @param mapNameOrNull the map name. May be null if this is not a map event (e.g. cache event)
* @return {@link #FILTER_DOES_NOT_MATCH} if the event does not match the filter, otherwise
* the integer event type of the event to be published. This allows a filtering strategy
* to alter the type of event that is actually published, depending on the attributes of the
* individual event registration.
*/
int doFilter(EventFilter filter, Data dataKey, Object dataOldValue, Object dataValue, EntryEventType eventType,
String mapNameOrNull);
/**
* @return a new instance of {@link EntryEventDataCache} implementation to be used with this filtering strategy
*/
EntryEventDataCache getEntryEventDataCache();
}