/*
* 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.Address;
import com.hazelcast.nio.serialization.Data;
import java.util.Collection;
/**
* A cache for {@link EntryEventData}. Instances of this interface are obtained by {@link FilteringStrategy}s. This provides a
* chance for filtering strategies to optimize event data caching implementation. This is not a general-purpose cache, rather it
* is meant to be used within the context of processing a single entry event in single-threaded code. This will
* allow creating less instances that are shared between listener registrations. The concrete number of created instances
* depends on the implementation. Every new event will need to obtain a new instance of the {@link EntryEventDataCache}.
*
* @see MapEventPublisherImpl#publishEvent(Collection, Address, String, EntryEventType, Data, Object, Object, Object)
*/
public interface EntryEventDataCache {
/**
* If an {@link EntryEventData} for the given parameters is already cached then return the cached value, otherwise create,
* cache and return the {@link EntryEventData}.
*
* @param mapName name of map
* @param caller the address of the caller that caused the event
* @param dataKey the key of the event map entry
* @param newValue the new value of the map entry
* @param oldValue the old value of the map entry
* @param mergingValue the value used when performing a merge operation in case of a {@link EntryEventType#MERGED} event.
* This value together with the old value produced the new value.
* @param eventType the event type
* @param includingValues if all of the entry values need to be included in the returned {@link EntryEventData}
* @return {@link EntryEventData} already cached in {@code Map eventDataPerEventType} for the given {@code eventType} or
* if not already cached, a new {@link EntryEventData} object.
*/
EntryEventData getOrCreateEventData(String mapName, Address caller, Data dataKey, Object newValue, Object oldValue,
Object mergingValue, int eventType, boolean includingValues);
/**
* Indicate whether event data have been created and are cached in this cache or not. If this method returns false, then
* {@code eventDataIncludingValues.size() + eventDataExcludingValues.size() > 0}.
*
* @return {@code true} if event data were not created in this cache, otherwise false.
*/
boolean isEmpty();
/**
* Return {@link EntryEventData} created & cached by invocations to
* {@link #getOrCreateEventData(String, Address, Data, Object, Object, Object, int, boolean)}, including values in
* the {@link EntryEventData} object.
*
* @return {@link EntryEventData} created & cached including values. When no such {@link EntryEventData} exist, may
* return {@code null} or empty collection.
*/
Collection<EntryEventData> eventDataIncludingValues();
/**
* Return {@link EntryEventData} created & cached by invocations to
* {@link #getOrCreateEventData(String, Address, Data, Object, Object, Object, int, boolean)}, excluding values from
* the {@link EntryEventData} object.
*
* @return {@link EntryEventData} created & cached excluding values. When no such {@link EntryEventData} exist, may
* return {@code null} or empty collection.
*/
Collection<EntryEventData> eventDataExcludingValues();
}