LocatorHelper.java example

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/*
 * 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.internal.locator.wan;

import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;

import org.apache.geode.distributed.internal.InternalLocator;
import org.apache.geode.cache.client.internal.locator.wan.LocatorMembershipListener;
import org.apache.geode.distributed.internal.WanLocatorDiscoverer;
import org.apache.geode.internal.CopyOnWriteHashSet;
import org.apache.geode.internal.admin.remote.DistributionLocatorId;

/**
 * This is a helper class which helps to add the locator information to the allLocatorInfoMap.
 * 
 *
 */
public class LocatorHelper {

  public final static Object locatorObject = new Object();

  /**
   * 
   * This methods add the given locator to allLocatorInfoMap. It also invokes a locatorlistener to
   * inform other locators in allLocatorInfoMap about this newly added locator.
   * 
   * @param distributedSystemId
   * @param locator
   * @param locatorListener
   * @param sourceLocator
   */
  public static boolean addLocator(int distributedSystemId, DistributionLocatorId locator,
      LocatorMembershipListener locatorListener, DistributionLocatorId sourceLocator) {
    ConcurrentHashMap<Integer, Set<DistributionLocatorId>> allLocatorsInfo =
        (ConcurrentHashMap<Integer, Set<DistributionLocatorId>>) locatorListener
            .getAllLocatorsInfo();
    Set<DistributionLocatorId> locatorsSet = new CopyOnWriteHashSet<DistributionLocatorId>();
    locatorsSet.add(locator);
    Set<DistributionLocatorId> existingValue =
        allLocatorsInfo.putIfAbsent(distributedSystemId, locatorsSet);
    if (existingValue != null) {
      if (!existingValue.contains(locator)) {
        existingValue.add(locator);
        addServerLocator(distributedSystemId, locatorListener, locator);
        locatorListener.locatorJoined(distributedSystemId, locator, sourceLocator);
      } else {
        return false;
      }
    } else {
      addServerLocator(distributedSystemId, locatorListener, locator);
      locatorListener.locatorJoined(distributedSystemId, locator, sourceLocator);
    }
    return true;
  }

  /**
   * This methods decides whether the given locator is server locator, if so then add this locator
   * in allServerLocatorsInfo map.
   * 
   * @param distributedSystemId
   * @param locatorListener
   * @param locator
   */
  private static void addServerLocator(Integer distributedSystemId,
      LocatorMembershipListener locatorListener, DistributionLocatorId locator) {
    ConcurrentHashMap<Integer, Set<String>> allServerLocatorsInfo =
        (ConcurrentHashMap<Integer, Set<String>>) locatorListener.getAllServerLocatorsInfo();

    Set<String> locatorsSet = new CopyOnWriteHashSet<String>();
    locatorsSet.add(locator.toString());
    Set<String> existingValue = allServerLocatorsInfo.putIfAbsent(distributedSystemId, locatorsSet);
    if (existingValue != null) {
      if (!existingValue.contains(locator.toString())) {
        existingValue.add(locator.toString());
      }
    }
  }

  /**
   * This method adds the map of locatorsinfo sent by other locator to this locator's allLocatorInfo
   * 
   * @param locators
   * @param locatorListener
   */
  public static boolean addExchangedLocators(Map<Integer, Set<DistributionLocatorId>> locators,
      LocatorMembershipListener locatorListener) {

    ConcurrentHashMap<Integer, Set<DistributionLocatorId>> allLocators =
        (ConcurrentHashMap<Integer, Set<DistributionLocatorId>>) locatorListener
            .getAllLocatorsInfo();
    if (!allLocators.equals(locators)) {
      for (Map.Entry<Integer, Set<DistributionLocatorId>> entry : locators.entrySet()) {
        Set<DistributionLocatorId> existingValue = allLocators.putIfAbsent(entry.getKey(),
            new CopyOnWriteHashSet<DistributionLocatorId>(entry.getValue()));

        if (existingValue != null) {
          Set<DistributionLocatorId> localLocators = allLocators.get(entry.getKey());
          if (!localLocators.equals(entry.getValue())) {
            entry.getValue().removeAll(localLocators);
            for (DistributionLocatorId locator : entry.getValue()) {
              localLocators.add(locator);
              addServerLocator(entry.getKey(), locatorListener, locator);
              locatorListener.locatorJoined(entry.getKey(), locator, null);
            }
          }

        } else {
          for (DistributionLocatorId locator : entry.getValue()) {
            addServerLocator(entry.getKey(), locatorListener, locator);
            locatorListener.locatorJoined(entry.getKey(), locator, null);
          }
        }
      }
      return true;
    }
    return false;
  }

}