extensions/geode-modules/src/main/java/org/apache/geode/modules/util/ContextMapper.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.modules.util;

import java.util.HashMap;
import java.util.Map;

import org.apache.catalina.session.ManagerBase;


/**
 * This basic singleton class maps context paths to manager instances.
 * <p>
 * This class exists for a particular corner case described here. Consider a client-server
 * environment with empty client regions *and* the need to fire HttpSessionListener destroy events.
 * When a session expires, in this scenario, the Gemfire destroy events originate on the server and,
 * with some Gemfire hackery, the destroyed object ends up as the event's callback argument. At the
 * point that the CacheListener then gets the event, the re-constituted session object has no
 * manager associated and so we need to re-attach a manager to it so that events can be fired
 * correctly.
 */

public class ContextMapper {

  private static final Map<String, ManagerBase> managers = new HashMap<String, ManagerBase>();

  private ContextMapper() {
    // This is a singleton
  }

  public static void addContext(String path, ManagerBase manager) {
    managers.put(path, manager);
  }

  public static ManagerBase getContext(String path) {
    return managers.get(path);
  }

  public static ManagerBase removeContext(String path) {
    return managers.remove(path);
  }
}