/*
    * 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.client;
  
  import com.google.common.util.concurrent.Uninterruptibles;
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.concurrent.ExecutorService;
  import java.util.concurrent.TimeUnit;
  import java.util.concurrent.atomic.AtomicInteger;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.hbase.HBaseConfiguration;
  import org.apache.hadoop.hbase.ServerName;
  import org.apache.hadoop.hbase.TableName;
  import org.apache.hadoop.hbase.Waiter;
  import org.apache.hadoop.hbase.testclassification.ClientTests;
  import org.apache.hadoop.hbase.testclassification.SmallTests;
  import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
  import org.junit.Assert;
  import org.junit.Test;
  import org.junit.experimental.categories.Category;
  
  @Category({ClientTests.class, SmallTests.class})
  public class TestMasterAddressRefresher {
  
    static class DummyConnection implements Connection {
      private final Configuration conf;
  
      DummyConnection(Configuration conf) {
        this.conf = conf;
      }
  
      @Override
      public Configuration getConfiguration() {
        return conf;
      }
  
      @Override
      public Table getTable(TableName tableName) throws IOException {
        return null;
      }
  
      @Override
      public Table getTable(TableName tableName, ExecutorService pool) throws IOException {
        return null;
      }
  
      @Override
      public BufferedMutator getBufferedMutator(TableName tableName) throws IOException {
        return null;
      }
  
      @Override
      public BufferedMutator getBufferedMutator(BufferedMutatorParams params) throws IOException {
        return null;
      }
  
      @Override
      public RegionLocator getRegionLocator(TableName tableName) throws IOException {
        return null;
      }
  
      @Override
      public Admin getAdmin() throws IOException {
        return null;
      }
  
      @Override
      public String getClusterId() throws IOException {
        return null;
      }
  
      @Override
      public void close() throws IOException {
  
      }
  
      @Override
      public boolean isClosed() {
        return false;
      }
  
      @Override
     public void abort(String why, Throwable e) {
 
     }
 
     @Override
     public boolean isAborted() {
       return false;
     }
   }
 
   private static class DummyMasterRegistry extends MasterRegistry {
 
     private final AtomicInteger getMastersCallCounter = new AtomicInteger(0);
     private final List<Long> callTimeStamps = new ArrayList<>();
 
     @Override
     public void init(Connection connection) throws IOException {
       super.init(connection);
     }
 
     @Override
     List<ServerName> getMasters() {
       getMastersCallCounter.incrementAndGet();
       callTimeStamps.add(EnvironmentEdgeManager.currentTime());
       return new ArrayList<>();
     }
 
     public int getMastersCount() {
       return getMastersCallCounter.get();
     }
 
     public List<Long> getCallTimeStamps() {
       return callTimeStamps;
     }
   }
 
   @Test
   public void testPeriodicMasterEndPointRefresh() throws IOException {
     Configuration conf = HBaseConfiguration.create();
     // Refresh every 1 second.
     conf.setLong(MasterAddressRefresher.PERIODIC_REFRESH_INTERVAL_SECS, 1);
     conf.setLong(MasterAddressRefresher.MIN_SECS_BETWEEN_REFRESHES, 0);
     final DummyMasterRegistry registry = new DummyMasterRegistry();
     registry.init(new DummyConnection(conf));
     // Wait for > 3 seconds to see that at least 3 getMasters() RPCs have been made.
     Waiter.waitFor(
         conf, 5000, new Waiter.Predicate<Exception>() {
           @Override
           public boolean evaluate() throws Exception {
             return registry.getMastersCount() > 3;
           }
         });
   }
 
   @Test
   public void testDurationBetweenRefreshes() throws IOException {
     Configuration conf = HBaseConfiguration.create();
     // Disable periodic refresh
     conf.setLong(MasterAddressRefresher.PERIODIC_REFRESH_INTERVAL_SECS, Integer.MAX_VALUE);
     // A minimum duration of 1s between refreshes
     conf.setLong(MasterAddressRefresher.MIN_SECS_BETWEEN_REFRESHES, 1);
     DummyMasterRegistry registry = new DummyMasterRegistry();
     registry.init(new DummyConnection(conf));
     // Issue a ton of manual refreshes.
     for (int i = 0; i < 10000; i++) {
       registry.masterAddressRefresher.refreshNow();
       Uninterruptibles.sleepUninterruptibly(1, TimeUnit.MILLISECONDS);
     }
     // Overall wait time is 10000 ms, so the number of requests should be <=10
     List<Long> callTimeStamps = registry.getCallTimeStamps();
     // Actual calls to getMasters() should be much lower than the refresh count.
     Assert.assertTrue(
         String.valueOf(registry.getMastersCount()), registry.getMastersCount() <= 20);
     Assert.assertTrue(callTimeStamps.size() > 0);
     // Verify that the delta between subsequent RPCs is at least 1sec as configured.
     for (int i = 1; i < callTimeStamps.size() - 1; i++) {
       long delta = callTimeStamps.get(i) - callTimeStamps.get(i - 1);
       // Few ms cushion to account for any env jitter.
       Assert.assertTrue(callTimeStamps.toString(), delta > 990);
     }
   }
 }