geode-core/src/main/java/org/apache/geode/cache/client/ClientRegionShortcut.java

/*
 * 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.client;

import org.apache.geode.cache.DataPolicy;
import org.apache.geode.cache.EvictionAction;
import org.apache.geode.cache.EvictionAlgorithm;
import org.apache.geode.cache.EvictionAttributes;
import org.apache.geode.cache.RegionAttributes;

/**
 * Each enum represents a predefined {@link RegionAttributes} in a {@link ClientCache}. These enum
 * values can be used to create regions using a {@link ClientRegionFactory} obtained by calling
 * {@link ClientCache#createClientRegionFactory(ClientRegionShortcut)}.
 * <p>
 * Another way to use predefined region attributes is in cache.xml by setting the refid attribute on
 * a region element or region-attributes element to the string of each value.
 *
 * @since GemFire 6.5
 */
public enum ClientRegionShortcut {
  /**
   * A PROXY region has no local state and forwards all operations to a server. The actual
   * RegionAttributes for a PROXY set the {@link DataPolicy} to {@link DataPolicy#EMPTY}.
   */
  PROXY,

  /**
   * A CACHING_PROXY region has local state but can also send operations to a server. If the local
   * state is not found then the operation is sent to the server and the local state is updated to
   * contain the server result. The actual RegionAttributes for a CACHING_PROXY set the
   * {@link DataPolicy} to {@link DataPolicy#NORMAL}.
   */
  CACHING_PROXY,

  /**
   * A CACHING_PROXY_HEAP_LRU region has local state but can also send operations to a server. If
   * the local state is not found then the operation is sent to the server and the local state is
   * updated to contain the server result. It will also destroy entries once it detects that the
   * java vm is running low of memory. The actual RegionAttributes for a CACHING_PROXY_HEAP_LRU set
   * the {@link DataPolicy} to {@link DataPolicy#NORMAL}. and {@link EvictionAttributes} are set to
   * {@link EvictionAlgorithm#LRU_HEAP} with {@link EvictionAction#LOCAL_DESTROY}.
   */
  CACHING_PROXY_HEAP_LRU,
  /**
   * A CACHING_PROXY_OVERFLOW region has local state but can also send operations to a server. If
   * the local state is not found then the operation is sent to the server and the local state is
   * updated to contain the server result. It will also move the values of entries to disk once it
   * detects that the java vm is running low of memory. The actual RegionAttributes for a
   * CACHING_PROXY_OVERFLOW set the {@link DataPolicy} to {@link DataPolicy#NORMAL}. and
   * {@link EvictionAttributes} are set to {@link EvictionAlgorithm#LRU_HEAP} with
   * {@link EvictionAction#OVERFLOW_TO_DISK}.
   */
  CACHING_PROXY_OVERFLOW,

  /**
   * A LOCAL region only has local state and never sends operations to a server. The actual
   * RegionAttributes for a LOCAL region set the {@link DataPolicy} to {@link DataPolicy#NORMAL}.
   */
  LOCAL,
  /**
   * A LOCAL_PERSISTENT region only has local state and never sends operations to a server but it
   * does write its state to disk and can recover that state when the region is created. The actual
   * RegionAttributes for a LOCAL_PERSISTENT region set the {@link DataPolicy} to
   * {@link DataPolicy#PERSISTENT_REPLICATE}.
   */
  LOCAL_PERSISTENT,
  /**
   * A LOCAL_HEAP_LRU region only has local state and never sends operations to a server. It will
   * also destroy entries once it detects that the java vm is running low of memory. The actual
   * RegionAttributes for a LOCAL_HEAP_LRU region set the {@link DataPolicy} to
   * {@link DataPolicy#NORMAL} and {@link EvictionAttributes} are set to
   * {@link EvictionAlgorithm#LRU_HEAP} with {@link EvictionAction#LOCAL_DESTROY}.
   */
  LOCAL_HEAP_LRU,
  /**
   * A LOCAL_OVERFLOW region only has local state and never sends operations to a server. It will
   * also move the values of entries to disk once it detects that the java vm is running low of
   * memory. The actual RegionAttributes for a LOCAL_OVERFLOW region set the {@link DataPolicy} to
   * {@link DataPolicy#NORMAL} and {@link EvictionAttributes} are set to
   * {@link EvictionAlgorithm#LRU_HEAP} with {@link EvictionAction#OVERFLOW_TO_DISK}.
   */
  LOCAL_OVERFLOW,
  /**
   * A LOCAL_PERSISTENT_OVERFLOW region only has local state and never sends operations to a server
   * but it does write its state to disk and can recover that state when the region is created. It
   * will also remove the values of entries from memory once it detects that the java vm is running
   * low of memory. The actual RegionAttributes for a LOCAL_PERSISTENT_OVERFLOW region set the
   * {@link DataPolicy} to {@link DataPolicy#PERSISTENT_REPLICATE} and {@link EvictionAttributes}
   * are set to {@link EvictionAlgorithm#LRU_HEAP} with {@link EvictionAction#OVERFLOW_TO_DISK}.
   */
  LOCAL_PERSISTENT_OVERFLOW
}