/**
    *
    * 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.hadoop.hbase.master;
  
  import static org.junit.Assert.assertEquals;
  
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.List;
  import java.util.concurrent.atomic.AtomicInteger;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.hbase.Abortable;
  import org.apache.hadoop.hbase.HBaseTestingUtility;
  import org.apache.hadoop.hbase.HConstants;
  import org.apache.hadoop.hbase.HRegionInfo;
  import org.apache.hadoop.hbase.testclassification.MediumTests;
  import org.apache.hadoop.hbase.MiniHBaseCluster;
  import org.apache.hadoop.hbase.TableName;
  import org.apache.hadoop.hbase.ServerLoad;
  import org.apache.hadoop.hbase.ServerName;
  import org.apache.hadoop.hbase.client.Admin;
  import org.apache.hadoop.hbase.client.HTable;
  import org.apache.hadoop.hbase.client.Put;
  import org.apache.hadoop.hbase.client.Table;
  import org.apache.hadoop.hbase.regionserver.HRegion;
  import org.apache.hadoop.hbase.regionserver.Region;
  import org.apache.hadoop.hbase.util.Bytes;
  import org.apache.hadoop.hbase.util.JVMClusterUtil;
  import org.apache.hadoop.hbase.zookeeper.DrainingServerTracker;
  import org.apache.hadoop.hbase.zookeeper.RegionServerTracker;
  import org.apache.hadoop.hbase.zookeeper.ZKUtil;
  import org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher;
  import org.junit.AfterClass;
  import org.junit.Assert;
  import org.junit.BeforeClass;
  import org.junit.Test;
  import org.junit.experimental.categories.Category;
  import org.mockito.Mockito;
  
  @Category(MediumTests.class)
  public class TestAssignmentListener {
    private static final Log LOG = LogFactory.getLog(TestAssignmentListener.class);
  
    private static final HBaseTestingUtility TEST_UTIL = new HBaseTestingUtility();
    private static final Abortable abortable = new Abortable() {
      @Override
      public boolean isAborted() {
        return false;
      }
  
      @Override
      public void abort(String why, Throwable e) {
      }
    };
  
    static class DummyListener {
      protected AtomicInteger modified = new AtomicInteger(0);
  
      public void awaitModifications(int count) throws InterruptedException {
        while (!modified.compareAndSet(count, 0)) {
          Thread.sleep(100);
        }
      }
    }
  
    static class DummyAssignmentListener extends DummyListener implements AssignmentListener {
      private AtomicInteger closeCount = new AtomicInteger(0);
      private AtomicInteger openCount = new AtomicInteger(0);
  
      public DummyAssignmentListener() {
      }
  
      @Override
      public void regionOpened(final HRegionInfo regionInfo, final ServerName serverName) {
        LOG.info("Assignment open region=" + regionInfo + " server=" + serverName);
        openCount.incrementAndGet();
        modified.incrementAndGet();
      }
  
     @Override
     public void regionClosed(final HRegionInfo regionInfo) {
       LOG.info("Assignment close region=" + regionInfo);
       closeCount.incrementAndGet();
       modified.incrementAndGet();
     }
 
     public void reset() {
       openCount.set(0);
       closeCount.set(0);
     }
 
     public int getLoadCount() {
       return openCount.get();
     }
 
     public int getCloseCount() {
       return closeCount.get();
     }
   }
 
   static class DummyServerListener extends DummyListener implements ServerListener {
     private AtomicInteger removedCount = new AtomicInteger(0);
     private AtomicInteger addedCount = new AtomicInteger(0);
 
     public DummyServerListener() {
     }
 
     @Override
     public void serverAdded(final ServerName serverName) {
       LOG.info("Server added " + serverName);
       addedCount.incrementAndGet();
       modified.incrementAndGet();
     }
 
     @Override
     public void serverRemoved(final ServerName serverName) {
       LOG.info("Server removed " + serverName);
       removedCount.incrementAndGet();
       modified.incrementAndGet();
     }
 
     public void reset() {
       addedCount.set(0);
       removedCount.set(0);
     }
 
     public int getAddedCount() {
       return addedCount.get();
     }
 
     public int getRemovedCount() {
       return removedCount.get();
     }
   }
 
   @BeforeClass
   public static void beforeAllTests() throws Exception {
     TEST_UTIL.startMiniCluster(2);
   }
 
   @AfterClass
   public static void afterAllTests() throws Exception {
     TEST_UTIL.shutdownMiniCluster();
   }
 
   @Test(timeout=60000)
   public void testServerListener() throws IOException, InterruptedException {
     ServerManager serverManager = TEST_UTIL.getHBaseCluster().getMaster().getServerManager();
 
     DummyServerListener listener = new DummyServerListener();
     serverManager.registerListener(listener);
     try {
       MiniHBaseCluster miniCluster = TEST_UTIL.getMiniHBaseCluster();
 
       // Start a new Region Server
       miniCluster.startRegionServer();
       listener.awaitModifications(1);
       assertEquals(1, listener.getAddedCount());
       assertEquals(0, listener.getRemovedCount());
 
       // Start another Region Server
       listener.reset();
       miniCluster.startRegionServer();
       listener.awaitModifications(1);
       assertEquals(1, listener.getAddedCount());
       assertEquals(0, listener.getRemovedCount());
 
       int nrs = miniCluster.getRegionServerThreads().size();
 
       // Stop a Region Server
       listener.reset();
       miniCluster.stopRegionServer(nrs - 1);
       listener.awaitModifications(1);
       assertEquals(0, listener.getAddedCount());
       assertEquals(1, listener.getRemovedCount());
 
       // Stop another Region Server
       listener.reset();
       miniCluster.stopRegionServer(nrs - 2);
       listener.awaitModifications(1);
       assertEquals(0, listener.getAddedCount());
       assertEquals(1, listener.getRemovedCount());
     } finally {
       serverManager.unregisterListener(listener);
     }
   }
 
   @Test(timeout=60000)
   public void testAssignmentListener() throws IOException, InterruptedException {
     AssignmentManager am = TEST_UTIL.getHBaseCluster().getMaster().getAssignmentManager();
     Admin admin = TEST_UTIL.getHBaseAdmin();
 
     DummyAssignmentListener listener = new DummyAssignmentListener();
     am.registerListener(listener);
     try {
       final String TABLE_NAME_STR = "testtb";
       final TableName TABLE_NAME = TableName.valueOf(TABLE_NAME_STR);
       final byte[] FAMILY = Bytes.toBytes("cf");
 
       // Create a new table, with a single region
       LOG.info("Create Table");
       TEST_UTIL.createTable(TABLE_NAME, FAMILY);
       listener.awaitModifications(1);
       assertEquals(1, listener.getLoadCount());
       assertEquals(0, listener.getCloseCount());
 
       // Add some data
       Table table = new HTable(TEST_UTIL.getConfiguration(), TABLE_NAME);
       try {
         for (int i = 0; i < 10; ++i) {
           byte[] key = Bytes.toBytes("row-" + i);
           Put put = new Put(key);
           put.add(FAMILY, null, key);
           table.put(put);
         }
       } finally {
         table.close();
       }
 
       // Split the table in two
       LOG.info("Split Table");
       listener.reset();
       admin.split(TABLE_NAME, Bytes.toBytes("row-3"));
       listener.awaitModifications(3);
       assertEquals(2, listener.getLoadCount());     // daughters added
       assertEquals(1, listener.getCloseCount());    // parent removed
 
       // Wait for the Regions to be mergeable
       MiniHBaseCluster miniCluster = TEST_UTIL.getMiniHBaseCluster();
       int mergeable = 0;
       while (mergeable < 2) {
         Thread.sleep(100);
         admin.majorCompact(TABLE_NAME);
         mergeable = 0;
         for (JVMClusterUtil.RegionServerThread regionThread: miniCluster.getRegionServerThreads()) {
           for (Region region: regionThread.getRegionServer().getOnlineRegions(TABLE_NAME)) {
             mergeable += ((HRegion)region).isMergeable() ? 1 : 0;
           }
         }
       }
 
       // Merge the two regions
       LOG.info("Merge Regions");
       listener.reset();
       List<HRegionInfo> regions = admin.getTableRegions(TABLE_NAME);
       assertEquals(2, regions.size());
       admin.mergeRegions(regions.get(0).getEncodedNameAsBytes(),
         regions.get(1).getEncodedNameAsBytes(), true);
       listener.awaitModifications(3);
       assertEquals(1, admin.getTableRegions(TABLE_NAME).size());
       assertEquals(1, listener.getLoadCount());     // new merged region added
       assertEquals(2, listener.getCloseCount());    // daughters removed
 
       // Delete the table
       LOG.info("Drop Table");
       listener.reset();
       TEST_UTIL.deleteTable(TABLE_NAME);
       listener.awaitModifications(1);
       assertEquals(0, listener.getLoadCount());
       assertEquals(1, listener.getCloseCount());
     } finally {
       am.unregisterListener(listener);
     }
   }
 
   @Test
   public void testAddNewServerThatExistsInDraining() throws Exception {
     // Under certain circumstances, such as when we failover to the Backup
     // HMaster, the DrainingServerTracker is started with existing servers in
     // draining before all of the Region Servers register with the
     // ServerManager as "online".  This test is to ensure that Region Servers
     // are properly added to the ServerManager.drainingServers when they
     // register with the ServerManager under these circumstances.
     Configuration conf = TEST_UTIL.getConfiguration();
     ZooKeeperWatcher zooKeeper = new ZooKeeperWatcher(conf,
         "zkWatcher-NewServerDrainTest", abortable, true);
     String baseZNode = conf.get(HConstants.ZOOKEEPER_ZNODE_PARENT,
         HConstants.DEFAULT_ZOOKEEPER_ZNODE_PARENT);
     String drainingZNode = ZKUtil.joinZNode(baseZNode,
         conf.get("zookeeper.znode.draining.rs", "draining"));
 
     MasterServices services = Mockito.mock(MasterServices.class);
     HMaster master = Mockito.mock(HMaster.class);
     Mockito.when(master.getConfiguration()).thenReturn(conf);
 
     ServerName SERVERNAME_A = ServerName.valueOf("mockserverbulk_a.org", 1000, 8000);
     ServerName SERVERNAME_B = ServerName.valueOf("mockserverbulk_b.org", 1001, 8000);
     ServerName SERVERNAME_C = ServerName.valueOf("mockserverbulk_c.org", 1002, 8000);
 
     // We'll start with 2 servers in draining that existed before the
     // HMaster started.
     ArrayList<ServerName> drainingServers = new ArrayList<ServerName>();
     drainingServers.add(SERVERNAME_A);
     drainingServers.add(SERVERNAME_B);
 
     // We'll have 2 servers that come online AFTER the DrainingServerTracker
     // is started (just as we see when we failover to the Backup HMaster).
     // One of these will already be a draining server.
     HashMap<ServerName, ServerLoad> onlineServers = new HashMap<ServerName, ServerLoad>();
     onlineServers.put(SERVERNAME_A, ServerLoad.EMPTY_SERVERLOAD);
     onlineServers.put(SERVERNAME_C, ServerLoad.EMPTY_SERVERLOAD);
 
     // Create draining znodes for the draining servers, which would have been
     // performed when the previous HMaster was running.
     for (ServerName sn : drainingServers) {
       String znode = ZKUtil.joinZNode(drainingZNode, sn.getServerName());
       ZKUtil.createAndFailSilent(zooKeeper, znode);
     }
 
     // Now, we follow the same order of steps that the HMaster does to setup
     // the ServerManager, RegionServerTracker, and DrainingServerTracker.
     ServerManager serverManager = new ServerManager(master, services);
 
     RegionServerTracker regionServerTracker = new RegionServerTracker(
         zooKeeper, master, serverManager);
     regionServerTracker.start();
 
     DrainingServerTracker drainingServerTracker = new DrainingServerTracker(
         zooKeeper, master, serverManager);
     drainingServerTracker.start();
 
     // Confirm our ServerManager lists are empty.
     Assert.assertEquals(serverManager.getOnlineServers(),
         new HashMap<ServerName, ServerLoad>());
     Assert.assertEquals(serverManager.getDrainingServersList(),
         new ArrayList<ServerName>());
 
     // checkAndRecordNewServer() is how servers are added to the ServerManager.
     ArrayList<ServerName> onlineDrainingServers = new ArrayList<ServerName>();
     for (ServerName sn : onlineServers.keySet()){
       // Here's the actual test.
       serverManager.checkAndRecordNewServer(sn, onlineServers.get(sn));
       if (drainingServers.contains(sn)){
         onlineDrainingServers.add(sn);  // keeping track for later verification
       }
     }
 
     // Verify the ServerManager lists are correctly updated.
     Assert.assertEquals(serverManager.getOnlineServers(), onlineServers);
     Assert.assertEquals(serverManager.getDrainingServersList(),
         onlineDrainingServers);
   }
 }