/*
 * 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.cache;

/**
 * Gemfire Context passed to <code>PartitionResolver</code> to compute the data location
 *
 *
 * @see PartitionResolver
 * @since GemFire 6.0
 */
public interface EntryOperation<K, V> {

  /**
   * Returns the region to which this cached object belongs or the region that raised this event for
   * <code>RegionEvent</code>s.
   *
   * @return the region associated with this object or the region that raised this event.
   */
  Region<K, V> getRegion();

  /**
   * Return a description of the operation that triggered this event. It may return null and should
   * not be used to generate routing object in
   * {@link PartitionResolver#getRoutingObject(EntryOperation)}
   *
   * @return the operation that triggered this event.
   * @since GemFire 6.0
   * @deprecated
   */
  Operation getOperation();

  /**
   * Returns the key.
   *
   * @return the key
   */
  K getKey();

  /**
   * Returns the callbackArgument passed to the method that generated this event. Provided primarily
   * in case this object or region has already been destroyed. See the {@link Region} interface
   * methods that take a callbackArgument parameter. Only fields on the key should be used when
   * creating the routing object.
   *
   * @return the callbackArgument associated with this event. <code>null</code> is returned if the
   *         callback argument is not propagated to the event. This happens for events given to
   *         {@link TransactionListener} and to {@link CacheListener} on the remote side of a
   *         transaction commit.
   */
  Object getCallbackArgument();

  /**
   * Returns <code>true</code> if the callback argument is "available". Not available means that the
   * callback argument may have existed but it could not be obtained. Note that
   * {@link #getCallbackArgument} will return <code>null</code> when this method returns
   * <code>false</code>.
   *
   * @since GemFire 6.0
   */
  boolean isCallbackArgumentAvailable();

  /**
   * Returns the value but may return null and should not be used to generate routing object in
   * {@link PartitionResolver#getRoutingObject(EntryOperation)}. Only fields on the key should be
   * used when creating the routing object.
   *
   * @return the value.
   * @deprecated
   */
  V getNewValue();
}