| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more contributor license |
| * agreements. See the NOTICE file distributed with this work for additional information regarding |
| * copyright ownership. The ASF licenses this file to You 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 org.apache.geode; |
| |
| import java.io.DataInput; |
| import java.io.DataOutput; |
| import java.io.IOException; |
| |
| |
| /** |
| * This interface defines a contract between the application and GemFire that allows GemFire to |
| * determine whether an application object contains a delta, allows GemFire to extract the delta |
| * from an application object, and generate a new application object by applying a delta to an |
| * existing application object. The difference in object state is contained in the |
| * {@link DataOutput} and {@link DataInput} parameters. |
| * |
| * @since GemFire 6.1 |
| * |
| */ |
| public interface Delta { |
| |
| /** |
| * Returns true if this object has pending changes it can write out as a delta. |
| * Returns false if this object must be transmitted in its entirety. |
| */ |
| boolean hasDelta(); |
| |
| /** |
| * This method is invoked on an application object at the delta sender, if GemFire determines the |
| * presence of a delta by calling {@link Delta#hasDelta()} on the object. The delta is written to |
| * the {@link DataOutput} object provided by GemFire. |
| * |
| * Any delta state should be reset in this method. |
| * |
| */ |
| void toDelta(DataOutput out) throws IOException; |
| |
| |
| /** |
| * This method is invoked on an existing application object when an update is received as a delta. |
| * This method throws an {@link InvalidDeltaException} when the delta in the {@link DataInput} |
| * cannot be applied to the object. GemFire automatically handles an {@link InvalidDeltaException} |
| * by reattempting the update by sending the full application object. |
| * |
| */ |
| void fromDelta(DataInput in) throws IOException, InvalidDeltaException; |
| } |