com.hazelcast.map.MapInterceptor Maven / Gradle / Ivy
/*
* 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;
import com.hazelcast.nio.serialization.impl.BinaryInterface;
import java.io.Serializable;
/**
* MapInterceptor is used to intercept changes to the map, allowing access to the values before and
* after adding them to the map.
*
* MapInterceptors are chained when added to the map, which means that when an interceptor is added
* on node initialization, it could be added twice. To prevent this, make sure to implement the
* hashCode method to return the same value for every instance of the class.
*
* Serialized instances of this interface are used in client-member communication, so changing an implementation's binary format
* will render it incompatible with its previous versions.
*/
@BinaryInterface
public interface MapInterceptor extends Serializable {
/**
* Intercept the get operation before returning value.
* Return another object to change the return value of get(..)
* Returning null will cause the get(..) operation to return the original value,
* so return null if you do not want to change anything.
*
* Mutations made to the value do not affect the stored value. They do affect the returned value.
*
* @param value the original value to be returned as the result of get(..) operation
* @return the new value that will be returned by the get(..) operation
*/
Object interceptGet(Object value);
/**
* Called after the get(..) operation is completed.
*
* Mutations made to value do not affect the stored value.
*
* @param value the value returned as the result of the get(..) operation
*/
void afterGet(Object value);
/**
* Intercept the put operation before modifying the map data.
* Return the object to be put into the map.
* Returning null will cause the put(..) operation to operate as expected, namely no interception.
* Throwing an exception will cancel the put operation.
*
*
* @param oldValue the value currently in map
* @param newValue the new value to be put into the map
* @return new value after the intercept operation
*/
Object interceptPut(Object oldValue, Object newValue);
/**
* Called after the put(..) operation is completed.
*
*
* @param value the value returned as the result of the put(..) operation
*/
void afterPut(Object value);
/**
* Intercept remove operation before removing the data.
* Return the object to be returned as the result of the remove operation.
* Throwing an exception will cancel the remove operation.
*
*
* @param removedValue the existing value to be removed
* @return the value to be returned as the result of remove operation
*/
Object interceptRemove(Object removedValue);
/**
* Called after the remove(..) operation is completed.
*
*
* @param value the value returned as the result of the remove(..) operation
*/
void afterRemove(Object value);
}