/**
    * 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 static org.junit.Assert.assertEquals;
  import static org.junit.Assert.assertFalse;
  import static org.junit.Assert.assertNotNull;
  import static org.junit.Assert.assertTrue;
  import static org.junit.Assert.fail;
  import static org.mockito.Matchers.any;
  import static org.mockito.Matchers.anyBoolean;
  import static org.mockito.Matchers.anyInt;
  import static org.mockito.Mockito.when;
  
  import java.io.IOException;
  import java.util.Iterator;
  import java.util.concurrent.ExecutorService;
  import java.util.concurrent.Executors;
  
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.hbase.Cell;
  import org.apache.hadoop.hbase.CellScanner;
  import org.apache.hadoop.hbase.KeyValue;
  import org.apache.hadoop.hbase.KeyValue.Type;
  import org.apache.hadoop.hbase.RegionLocations;
  import org.apache.hadoop.hbase.TableName;
  import org.apache.hadoop.hbase.ipc.RpcControllerFactory;
  import org.apache.hadoop.hbase.testclassification.SmallTests;
  import org.junit.After;
  import org.junit.Before;
  import org.junit.Test;
  import org.junit.experimental.categories.Category;
  import org.mockito.InOrder;
  import org.mockito.Mockito;
  import org.mockito.invocation.InvocationOnMock;
  import org.mockito.stubbing.Answer;
  
  /**
   * Test the ClientScanner.
   */
  @Category(SmallTests.class)
  public class TestClientScanner {
  
    Scan scan;
    ExecutorService pool;
    Configuration conf;
  
    ClusterConnection clusterConn;
    RpcRetryingCallerFactory rpcFactory;
    RpcControllerFactory controllerFactory;
  
    @Before
    @SuppressWarnings("deprecation")
    public void setup() throws IOException {
      clusterConn = Mockito.mock(ClusterConnection.class);
      rpcFactory = Mockito.mock(RpcRetryingCallerFactory.class);
      controllerFactory = Mockito.mock(RpcControllerFactory.class);
      pool = Executors.newSingleThreadExecutor();
      scan = new Scan();
      conf = new Configuration();
      Mockito.when(clusterConn.getConfiguration()).thenReturn(conf);
    }
  
    @After
    public void teardown() {
      if (null != pool) {
        pool.shutdownNow();
      }
    }
  
    private static class MockClientScanner extends ClientScanner {
  
      private boolean rpcFinished = false;
      private boolean rpcFinishedFired = false;
  
      public MockClientScanner(final Configuration conf, final Scan scan, final TableName tableName,
          ClusterConnection connection, RpcRetryingCallerFactory rpcFactory,
          RpcControllerFactory controllerFactory, ExecutorService pool, int primaryOperationTimeout)
          throws IOException {
        super(conf, scan, tableName, connection, rpcFactory, controllerFactory, pool,
            primaryOperationTimeout);
      }
  
      @Override
     protected boolean nextScanner(int nbRows, final boolean done) throws IOException {
       if (!rpcFinished) {
         return super.nextScanner(nbRows, done);
       }
 
       // Enforce that we don't short-circuit more than once
       if (rpcFinishedFired) {
         throw new RuntimeException("Expected nextScanner to only be called once after " +
             " short-circuit was triggered.");
       }
       rpcFinishedFired = true;
       return false;
     }
 
     @Override
     protected ScannerCallableWithReplicas getScannerCallable(byte [] localStartKey,
         int nbRows) {
       scan.setStartRow(localStartKey);
       ScannerCallable s =
           new ScannerCallable(getConnection(), getTable(), scan, this.scanMetrics,
               this.rpcControllerFactory);
       s.setCaching(nbRows);
       ScannerCallableWithReplicas sr = new ScannerCallableWithReplicas(getTable(), getConnection(),
        s, pool, primaryOperationTimeout, scan,
        getRetries(), scannerTimeout, caching, conf, caller);
       return sr;
     }
 
     public void setRpcFinished(boolean rpcFinished) {
       this.rpcFinished = rpcFinished;
     }
   }
 
   @Test
   @SuppressWarnings("unchecked")
   public void testNoResultsHint() throws IOException {
     final Result[] results = new Result[1];
     KeyValue kv1 = new KeyValue("row".getBytes(), "cf".getBytes(), "cq".getBytes(), 1,
         Type.Maximum);
     results[0] = Result.create(new Cell[] {kv1});
 
     RpcRetryingCaller<Result[]> caller = Mockito.mock(RpcRetryingCaller.class);
 
     Mockito.when(rpcFactory.<Result[]> newCaller()).thenReturn(caller);
     Mockito.when(caller.callWithoutRetries(Mockito.any(RetryingCallable.class),
       Mockito.anyInt())).thenAnswer(new Answer<Result[]>() {
         private int count = 0;
         @Override
         public Result[] answer(InvocationOnMock invocation) throws Throwable {
             ScannerCallableWithReplicas callable = invocation.getArgumentAt(0,
                 ScannerCallableWithReplicas.class);
           switch (count) {
             case 0: // initialize
             case 2: // detect no more results
             case 3: // close
               count++;
               return null;
             case 1:
               count++;
               callable.setHasMoreResultsContext(false);
               return results;
             default:
               throw new RuntimeException("Expected only 2 invocations");
           }
         }
     });
 
     // Set a much larger cache and buffer size than we'll provide
     scan.setCaching(100);
     scan.setMaxResultSize(1000*1000);
 
     try (MockClientScanner scanner = new MockClientScanner(conf, scan, TableName.valueOf("table"),
         clusterConn, rpcFactory, controllerFactory, pool, Integer.MAX_VALUE)) {
 
       scanner.setRpcFinished(true);
 
       InOrder inOrder = Mockito.inOrder(caller);
 
       scanner.loadCache();
 
       // One for initializeScannerInConstruction()
       // One for fetching the results
       // One for fetching null results and quit as we do not have moreResults hint.
       inOrder.verify(caller, Mockito.times(3)).callWithoutRetries(
           Mockito.any(RetryingCallable.class), Mockito.anyInt());
 
       assertEquals(1, scanner.cache.size());
       Result r = scanner.cache.poll();
       assertNotNull(r);
       CellScanner cs = r.cellScanner();
       assertTrue(cs.advance());
       assertEquals(kv1, cs.current());
       assertFalse(cs.advance());
     }
   }
 
   @Test
   @SuppressWarnings("unchecked")
   public void testSizeLimit() throws IOException {
     final Result[] results = new Result[1];
     KeyValue kv1 = new KeyValue("row".getBytes(), "cf".getBytes(), "cq".getBytes(), 1,
         Type.Maximum);
     results[0] = Result.create(new Cell[] {kv1});
 
     RpcRetryingCaller<Result[]> caller = Mockito.mock(RpcRetryingCaller.class);
 
     Mockito.when(rpcFactory.<Result[]> newCaller()).thenReturn(caller);
     Mockito.when(caller.callWithoutRetries(Mockito.any(RetryingCallable.class),
       Mockito.anyInt())).thenAnswer(new Answer<Result[]>() {
         private int count = 0;
         @Override
         public Result[] answer(InvocationOnMock invocation) throws Throwable {
           ScannerCallableWithReplicas callable = invocation.getArgumentAt(0,
               ScannerCallableWithReplicas.class);
           switch (count) {
             case 0: // initialize
             case 2: // close
               count++;
               return null;
             case 1:
               count++;
               callable.setHasMoreResultsContext(true);
               // if we set false here the implementation will trigger a close
               callable.setServerHasMoreResults(true);
               return results;
             default:
               throw new RuntimeException("Expected only 2 invocations");
           }
         }
     });
 
     Mockito.when(rpcFactory.<Result[]> newCaller()).thenReturn(caller);
 
     // Set a much larger cache
     scan.setCaching(100);
     // The single key-value will exit the loop
     scan.setMaxResultSize(1);
 
     try (MockClientScanner scanner = new MockClientScanner(conf, scan, TableName.valueOf("table"),
         clusterConn, rpcFactory, controllerFactory, pool, Integer.MAX_VALUE)) {
 
       // Due to initializeScannerInConstruction()
       Mockito.verify(caller).callWithoutRetries(Mockito.any(RetryingCallable.class),
           Mockito.anyInt());
 
       InOrder inOrder = Mockito.inOrder(caller);
 
       scanner.loadCache();
 
       inOrder.verify(caller, Mockito.times(2)).callWithoutRetries(
           Mockito.any(RetryingCallable.class), Mockito.anyInt());
 
       assertEquals(1, scanner.cache.size());
       Result r = scanner.cache.poll();
       assertNotNull(r);
       CellScanner cs = r.cellScanner();
       assertTrue(cs.advance());
       assertEquals(kv1, cs.current());
       assertFalse(cs.advance());
     }
   }
 
   @Test
   @SuppressWarnings("unchecked")
   public void testCacheLimit() throws IOException {
     KeyValue kv1 = new KeyValue("row1".getBytes(), "cf".getBytes(), "cq".getBytes(), 1,
         Type.Maximum), kv2 = new KeyValue("row2".getBytes(), "cf".getBytes(), "cq".getBytes(), 1,
         Type.Maximum), kv3 = new KeyValue("row3".getBytes(), "cf".getBytes(), "cq".getBytes(), 1,
         Type.Maximum);
     final Result[] results = new Result[] {Result.create(new Cell[] {kv1}),
         Result.create(new Cell[] {kv2}), Result.create(new Cell[] {kv3})};
 
     RpcRetryingCaller<Result[]> caller = Mockito.mock(RpcRetryingCaller.class);
 
     Mockito.when(rpcFactory.<Result[]> newCaller()).thenReturn(caller);
     Mockito.when(caller.callWithoutRetries(Mockito.any(RetryingCallable.class),
       Mockito.anyInt())).thenAnswer(new Answer<Result[]>() {
         private int count = 0;
         @Override
         public Result[] answer(InvocationOnMock invocation) throws Throwable {
           ScannerCallableWithReplicas callable = invocation.getArgumentAt(0,
               ScannerCallableWithReplicas.class);
           switch (count) {
             case 0: // initialize
             case 2: // close
               count++;
               return null;
             case 1:
               count++;
               callable.setHasMoreResultsContext(true);
               // if we set false here the implementation will trigger a close
               callable.setServerHasMoreResults(true);
               return results;
             default:
               throw new RuntimeException("Expected only 2 invocations");
           }
         }
     });
 
     Mockito.when(rpcFactory.<Result[]> newCaller()).thenReturn(caller);
 
     // Set a small cache
     scan.setCaching(1);
     // Set a very large size
     scan.setMaxResultSize(1000*1000);
 
     try (MockClientScanner scanner = new MockClientScanner(conf, scan, TableName.valueOf("table"),
         clusterConn, rpcFactory, controllerFactory, pool, Integer.MAX_VALUE)) {
 
       // Due to initializeScannerInConstruction()
       Mockito.verify(caller).callWithoutRetries(Mockito.any(RetryingCallable.class),
           Mockito.anyInt());
 
       InOrder inOrder = Mockito.inOrder(caller);
 
       scanner.loadCache();
 
       // Ensures that possiblyNextScanner isn't called at the end which would trigger
       // another call to callWithoutRetries
       inOrder.verify(caller, Mockito.times(2)).callWithoutRetries(
           Mockito.any(RetryingCallable.class), Mockito.anyInt());
 
       assertEquals(3, scanner.cache.size());
       Result r = scanner.cache.poll();
       assertNotNull(r);
       CellScanner cs = r.cellScanner();
       assertTrue(cs.advance());
       assertEquals(kv1, cs.current());
       assertFalse(cs.advance());
 
       r = scanner.cache.poll();
       assertNotNull(r);
       cs = r.cellScanner();
       assertTrue(cs.advance());
       assertEquals(kv2, cs.current());
       assertFalse(cs.advance());
 
       r = scanner.cache.poll();
       assertNotNull(r);
       cs = r.cellScanner();
       assertTrue(cs.advance());
       assertEquals(kv3, cs.current());
       assertFalse(cs.advance());
     }
   }
 
   @Test
   @SuppressWarnings("unchecked")
   public void testNoMoreResults() throws IOException {
     final Result[] results = new Result[1];
     KeyValue kv1 = new KeyValue("row".getBytes(), "cf".getBytes(), "cq".getBytes(), 1,
         Type.Maximum);
     results[0] = Result.create(new Cell[] {kv1});
 
     RpcRetryingCaller<Result[]> caller = Mockito.mock(RpcRetryingCaller.class);
 
     Mockito.when(rpcFactory.<Result[]> newCaller()).thenReturn(caller);
     Mockito.when(caller.callWithoutRetries(Mockito.any(RetryingCallable.class),
       Mockito.anyInt())).thenAnswer(new Answer<Result[]>() {
         private int count = 0;
         @Override
         public Result[] answer(InvocationOnMock invocation) throws Throwable {
           ScannerCallableWithReplicas callable = invocation.getArgumentAt(0,
               ScannerCallableWithReplicas.class);
           switch (count) {
             case 0: // initialize
             case 2: // close
               count++;
               return null;
             case 1:
               count++;
               callable.setHasMoreResultsContext(true);
               callable.setServerHasMoreResults(false);
               return results;
             default:
               throw new RuntimeException("Expected only 2 invocations");
           }
         }
     });
 
     Mockito.when(rpcFactory.<Result[]> newCaller()).thenReturn(caller);
 
     // Set a much larger cache and buffer size than we'll provide
     scan.setCaching(100);
     scan.setMaxResultSize(1000*1000);
 
     try (MockClientScanner scanner = new MockClientScanner(conf, scan, TableName.valueOf("table"),
         clusterConn, rpcFactory, controllerFactory, pool, Integer.MAX_VALUE)) {
 
       // Due to initializeScannerInConstruction()
       Mockito.verify(caller).callWithoutRetries(Mockito.any(RetryingCallable.class),
           Mockito.anyInt());
 
       scanner.setRpcFinished(true);
 
       InOrder inOrder = Mockito.inOrder(caller);
 
       scanner.loadCache();
 
       inOrder.verify(caller, Mockito.times(2)).callWithoutRetries(
           Mockito.any(RetryingCallable.class), Mockito.anyInt());
 
       assertEquals(1, scanner.cache.size());
       Result r = scanner.cache.poll();
       assertNotNull(r);
       CellScanner cs = r.cellScanner();
       assertTrue(cs.advance());
       assertEquals(kv1, cs.current());
       assertFalse(cs.advance());
     }
   }
 
   @Test
   @SuppressWarnings("unchecked")
   public void testMoreResults() throws IOException {
     final Result[] results1 = new Result[1];
     KeyValue kv1 = new KeyValue("row".getBytes(), "cf".getBytes(), "cq".getBytes(), 1,
         Type.Maximum);
     results1[0] = Result.create(new Cell[] {kv1});
 
     final Result[] results2 = new Result[1];
     KeyValue kv2 = new KeyValue("row2".getBytes(), "cf".getBytes(), "cq".getBytes(), 1,
         Type.Maximum);
     results2[0] = Result.create(new Cell[] {kv2});
 
 
     RpcRetryingCaller<Result[]> caller = Mockito.mock(RpcRetryingCaller.class);
 
     Mockito.when(rpcFactory.<Result[]> newCaller()).thenReturn(caller);
     Mockito.when(caller.callWithoutRetries(Mockito.any(RetryingCallable.class),
         Mockito.anyInt())).thenAnswer(new Answer<Result[]>() {
           private int count = 0;
           @Override
           public Result[] answer(InvocationOnMock invocation) throws Throwable {
             ScannerCallableWithReplicas callable = invocation.getArgumentAt(0,
                 ScannerCallableWithReplicas.class);
             switch (count) {
               case 0: // initialize
               case 3: // close
                 count++;
                 return null;
               case 1:
                 count++;
                 callable.setHasMoreResultsContext(true);
                 callable.setServerHasMoreResults(true);
                 return results1;
               case 2:
                 count++;
                 // The server reports back false WRT more results
                 callable.setHasMoreResultsContext(true);
                 callable.setServerHasMoreResults(false);
                 return results2;
               default:
                 throw new RuntimeException("Expected only 2 invocations");
             }
           }
       });
 
     // Set a much larger cache and buffer size than we'll provide
     scan.setCaching(100);
     scan.setMaxResultSize(1000*1000);
 
     try (MockClientScanner scanner = new MockClientScanner(conf, scan, TableName.valueOf("table"),
         clusterConn, rpcFactory, controllerFactory, pool, Integer.MAX_VALUE)) {
 
       // Due to initializeScannerInConstruction()
       Mockito.verify(caller).callWithoutRetries(Mockito.any(RetryingCallable.class),
           Mockito.anyInt());
 
       InOrder inOrder = Mockito.inOrder(caller);
       scanner.setRpcFinished(true);
 
       scanner.loadCache();
 
       inOrder.verify(caller, Mockito.times(3)).callWithoutRetries(
           Mockito.any(RetryingCallable.class), Mockito.anyInt());
 
       assertEquals(2, scanner.cache.size());
       Result r = scanner.cache.poll();
       assertNotNull(r);
       CellScanner cs = r.cellScanner();
       assertTrue(cs.advance());
       assertEquals(kv1, cs.current());
       assertFalse(cs.advance());
 
       r = scanner.cache.poll();
       assertNotNull(r);
       cs = r.cellScanner();
       assertTrue(cs.advance());
       assertEquals(kv2, cs.current());
       assertFalse(cs.advance());
     }
   }
 
   /**
    * Tests the case where all replicas of a region throw an exception. It should not cause a hang
    * but the exception should propagate to the client
    */
   @Test (timeout = 30000)
   public void testExceptionsFromReplicasArePropagated() throws IOException {
     scan.setConsistency(Consistency.TIMELINE);
 
     // Mock a caller which calls the callable for ScannerCallableWithReplicas,
     // but throws an exception for the actual scanner calls via callWithRetries.
     rpcFactory = new MockRpcRetryingCallerFactory(conf);
     conf.set(RpcRetryingCallerFactory.CUSTOM_CALLER_CONF_KEY,
       MockRpcRetryingCallerFactory.class.getName());
 
     // mock 3 replica locations
     when(clusterConn.locateRegion((TableName)any(), (byte[])any(), anyBoolean(),
       anyBoolean(), anyInt())).thenReturn(new RegionLocations(null, null, null));
 
     try (MockClientScanner scanner = new MockClientScanner(conf, scan, TableName.valueOf("table"),
       clusterConn, rpcFactory, new RpcControllerFactory(conf), pool, Integer.MAX_VALUE)) {
       Iterator<Result> iter = scanner.iterator();
       while (iter.hasNext()) {
         iter.next();
       }
       fail("Should have failed with RetriesExhaustedException");
     } catch (RetriesExhaustedException expected) {
 
     }
   }
 
   public static class MockRpcRetryingCallerFactory extends RpcRetryingCallerFactory {
 
     public MockRpcRetryingCallerFactory(Configuration conf) {
       super(conf);
     }
 
     @Override
     public <T> RpcRetryingCaller<T> newCaller() {
       return new RpcRetryingCaller<T>(0, 0, 0) {
         @Override
         public void cancel() {
         }
         @Override
         public T callWithRetries(RetryingCallable<T> callable, int callTimeout)
             throws IOException, RuntimeException {
           throw new IOException("Scanner exception");
         }
 
         @Override
         public T callWithoutRetries(RetryingCallable<T> callable, int callTimeout)
             throws IOException, RuntimeException {
           try {
             return callable.call(callTimeout);
           } catch (IOException e) {
             throw e;
           } catch (Exception e) {
             throw new RuntimeException(e);
           }
         }
       };
     }
 
   }
 
 }