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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.
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  package org.apache.hadoop.hbase.coprocessor;
  
  import static org.junit.Assert.assertFalse;
  import static org.junit.Assert.assertTrue;
  import static org.junit.Assert.fail;
  
  import java.io.IOException;
  
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.hbase.Abortable;
  import org.apache.hadoop.hbase.CoprocessorEnvironment;
  import org.apache.hadoop.hbase.HBaseTestingUtility;
  import org.apache.hadoop.hbase.HColumnDescriptor;
  import org.apache.hadoop.hbase.HRegionInfo;
  import org.apache.hadoop.hbase.HTableDescriptor;
  import org.apache.hadoop.hbase.testclassification.MediumTests;
  import org.apache.hadoop.hbase.MiniHBaseCluster;
  import org.apache.hadoop.hbase.TableName;
  import org.apache.hadoop.hbase.client.Admin;
  import org.apache.hadoop.hbase.master.HMaster;
  import org.apache.hadoop.hbase.master.MasterCoprocessorHost;
  import org.apache.hadoop.hbase.util.Bytes;
  import org.apache.hadoop.hbase.zookeeper.ZooKeeperNodeTracker;
  import org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher;
  import org.junit.AfterClass;
  import org.junit.BeforeClass;
  import org.junit.Test;
  import org.junit.experimental.categories.Category;
  
  /**
   * Tests unhandled exceptions thrown by coprocessors running on master.
   * Expected result is that the master will remove the buggy coprocessor from
   * its set of coprocessors and throw a org.apache.hadoop.hbase.exceptions.DoNotRetryIOException
   * back to the client.
   * (HBASE-4014).
   */
  @Category(MediumTests.class)
  public class TestMasterCoprocessorExceptionWithRemove {
  
    public static class MasterTracker extends ZooKeeperNodeTracker {
      public boolean masterZKNodeWasDeleted = false;
  
      public MasterTracker(ZooKeeperWatcher zkw, String masterNode, Abortable abortable) {
        super(zkw, masterNode, abortable);
      }
  
      @Override
      public synchronized void nodeDeleted(String path) {
        if (path.equals("/hbase/master")) {
          masterZKNodeWasDeleted = true;
        }
      }
    }
  
    public static class BuggyMasterObserver extends BaseMasterObserver {
      private boolean preCreateTableCalled;
      private boolean postCreateTableCalled;
      private boolean startCalled;
      private boolean postStartMasterCalled;
  
      @Override
      @SuppressWarnings("null")
      @edu.umd.cs.findbugs.annotations.SuppressWarnings(value="NP_NULL_ON_SOME_PATH",
        justification="Preconditions checks insure we are not going to dereference a null value")
      public void postCreateTable(ObserverContext<MasterCoprocessorEnvironment> env,
          HTableDescriptor desc, HRegionInfo[] regions) throws IOException {
        // Cause a NullPointerException and don't catch it: this should cause the
        // master to throw an o.apache.hadoop.hbase.DoNotRetryIOException to the
        // client.
        Integer i;
        i = null;
        i = i++;
      }
  
      public boolean wasCreateTableCalled() {
        return preCreateTableCalled && postCreateTableCalled;
      }
  
      @Override
      public void postStartMaster(ObserverContext<MasterCoprocessorEnvironment> ctx)
         throws IOException {
       postStartMasterCalled = true;
     }
 
     public boolean wasStartMasterCalled() {
       return postStartMasterCalled;
     }
 
     @Override
     public void start(CoprocessorEnvironment env) throws IOException {
       startCalled = true;
     }
 
     public boolean wasStarted() {
       return startCalled;
     }
   }
 
   private static HBaseTestingUtility UTIL = new HBaseTestingUtility();
 
   private static byte[] TEST_TABLE1 = Bytes.toBytes("observed_table1");
   private static byte[] TEST_FAMILY1 = Bytes.toBytes("fam1");
 
   private static byte[] TEST_TABLE2 = Bytes.toBytes("table2");
   private static byte[] TEST_FAMILY2 = Bytes.toBytes("fam2");
 
   @BeforeClass
   public static void setupBeforeClass() throws Exception {
     Configuration conf = UTIL.getConfiguration();
     conf.set(CoprocessorHost.MASTER_COPROCESSOR_CONF_KEY,
         BuggyMasterObserver.class.getName());
     UTIL.getConfiguration().setBoolean(CoprocessorHost.ABORT_ON_ERROR_KEY, false);
     UTIL.startMiniCluster();
   }
 
   @AfterClass
   public static void teardownAfterClass() throws Exception {
     UTIL.shutdownMiniCluster();
   }
 
   @Test(timeout=30000)
   public void testExceptionFromCoprocessorWhenCreatingTable()
       throws IOException {
     MiniHBaseCluster cluster = UTIL.getHBaseCluster();
 
     HMaster master = cluster.getMaster();
     MasterCoprocessorHost host = master.getMasterCoprocessorHost();
     BuggyMasterObserver cp = (BuggyMasterObserver)host.findCoprocessor(
         BuggyMasterObserver.class.getName());
     assertFalse("No table created yet", cp.wasCreateTableCalled());
 
     // Set a watch on the zookeeper /hbase/master node. If the master dies,
     // the node will be deleted.
     // Master should *NOT* die:
     // we are testing that the default setting of hbase.coprocessor.abortonerror
     // =false
     // is respected.
     ZooKeeperWatcher zkw = new ZooKeeperWatcher(UTIL.getConfiguration(),
       "unittest", new Abortable() {
       @Override
       public void abort(String why, Throwable e) {
         throw new RuntimeException("Fatal ZK error: " + why, e);
       }
       @Override
       public boolean isAborted() {
         return false;
       }
     });
 
     MasterTracker masterTracker = new MasterTracker(zkw,"/hbase/master",
         new Abortable() {
           @Override
           public void abort(String why, Throwable e) {
             throw new RuntimeException("Fatal Zookeeper tracker error, why=", e);
           }
           @Override
           public boolean isAborted() {
             return false;
           }
         });
 
     masterTracker.start();
     zkw.registerListener(masterTracker);
 
     // Test (part of the) output that should have be printed by master when it aborts:
     // (namely the part that shows the set of loaded coprocessors).
     // In this test, there is only a single coprocessor (BuggyMasterObserver).
     String coprocessorName =
         BuggyMasterObserver.class.getName();
     assertTrue(HMaster.getLoadedCoprocessors().contains(coprocessorName));
 
     HTableDescriptor htd1 = new HTableDescriptor(TableName.valueOf(TEST_TABLE1));
     htd1.addFamily(new HColumnDescriptor(TEST_FAMILY1));
 
     boolean threwDNRE = false;
     try {
       Admin admin = UTIL.getHBaseAdmin();
       admin.createTable(htd1);
     } catch (IOException e) {
       if (e.getClass().getName().equals("org.apache.hadoop.hbase.DoNotRetryIOException")) {
         threwDNRE = true;
       }
     } finally {
       assertTrue(threwDNRE);
     }
 
     // wait for a few seconds to make sure that the Master hasn't aborted.
     try {
       Thread.sleep(3000);
     } catch (InterruptedException e) {
       fail("InterruptedException while sleeping.");
     }
 
     assertFalse("Master survived coprocessor NPE, as expected.",
         masterTracker.masterZKNodeWasDeleted);
 
     String loadedCoprocessors = HMaster.getLoadedCoprocessors();
     assertTrue(loadedCoprocessors.contains(coprocessorName));
 
     // Verify that BuggyMasterObserver has been removed due to its misbehavior
     // by creating another table: should not have a problem this time.
     HTableDescriptor htd2 = new HTableDescriptor(TableName.valueOf(TEST_TABLE2));
     htd2.addFamily(new HColumnDescriptor(TEST_FAMILY2));
     Admin admin = UTIL.getHBaseAdmin();
     try {
       admin.createTable(htd2);
     } catch (IOException e) {
       fail("Failed to create table after buggy coprocessor removal: " + e);
     }
   }
 
 }