/*
    *
    * 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.apache.hadoop.hbase.HBaseTestCase.assertByteEquals;
  
  import java.io.IOException;
  import java.nio.ByteBuffer;
  import java.util.Arrays;
  import java.util.List;
  import java.util.NoSuchElementException;
  
  import junit.framework.TestCase;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.hbase.Cell;
  import org.apache.hadoop.hbase.CellScanner;
  import org.apache.hadoop.hbase.CellUtil;
  import org.apache.hadoop.hbase.KeyValue;
  import org.apache.hadoop.hbase.protobuf.generated.ClientProtos;
  import org.apache.hadoop.hbase.testclassification.SmallTests;
  import org.apache.hadoop.hbase.util.Bytes;
  import org.junit.experimental.categories.Category;
  
  @Category(SmallTests.class)
  public class TestResult extends TestCase {
  
    private static final Log LOG = LogFactory.getLog(TestResult.class.getName());
  
    static KeyValue[] genKVs(final byte[] row, final byte[] family,
                             final byte[] value,
                      final long timestamp,
                      final int cols) {
      KeyValue [] kvs = new KeyValue[cols];
  
      for (int i = 0; i < cols ; i++) {
        kvs[i] = new KeyValue(
            row, family, Bytes.toBytes(i),
            timestamp,
            Bytes.add(value, Bytes.toBytes(i)));
      }
      return kvs;
    }
  
    static final byte [] row = Bytes.toBytes("row");
    static final byte [] family = Bytes.toBytes("family");
    static final byte [] value = Bytes.toBytes("value");
  
    /**
     * Run some tests to ensure Result acts like a proper CellScanner.
     * @throws IOException
     */
    public void testResultAsCellScanner() throws IOException {
      Cell [] cells = genKVs(row, family, value, 1, 10);
      Arrays.sort(cells, KeyValue.COMPARATOR);
      Result r = Result.create(cells);
      assertSame(r, cells);
      // Assert I run over same result multiple times.
      assertSame(r.cellScanner(), cells);
      assertSame(r.cellScanner(), cells);
      // Assert we are not creating new object when doing cellscanner
      assertTrue(r == r.cellScanner());
    }
  
    private void assertSame(final CellScanner cellScanner, final Cell [] cells) throws IOException {
      int count = 0;
      while (cellScanner.advance()) {
        assertTrue(cells[count].equals(cellScanner.current()));
        count++;
      }
      assertEquals(cells.length, count);
    }
  
    public void testBasicGetColumn() throws Exception {
      KeyValue [] kvs = genKVs(row, family, value, 1, 100);
  
      Arrays.sort(kvs, KeyValue.COMPARATOR);
  
      Result r = Result.create(kvs);
  
      for (int i = 0; i < 100; ++i) {
       final byte[] qf = Bytes.toBytes(i);
 
       List<Cell> ks = r.getColumnCells(family, qf);
       assertEquals(1, ks.size());
       assertTrue(CellUtil.matchingQualifier(ks.get(0), qf));
       assertEquals(ks.get(0), r.getColumnLatestCell(family, qf));
     }
   }
 
   public void testCurrentOnEmptyCell() throws IOException {
     Result r = Result.create(new Cell[0]);
     assertFalse(r.advance());
     assertNull(r.current());
   }
 
   public void testAdvanceTwiceOnEmptyCell() throws IOException {
     Result r = Result.create(new Cell[0]);
     assertFalse(r.advance());
     try {
       r.advance();
       fail("NoSuchElementException should have been thrown!");
     } catch (NoSuchElementException ex) {
       LOG.debug("As expected: " + ex.getMessage());
     }
   }
 
   public void testMultiVersionGetColumn() throws Exception {
     KeyValue [] kvs1 = genKVs(row, family, value, 1, 100);
     KeyValue [] kvs2 = genKVs(row, family, value, 200, 100);
 
     KeyValue [] kvs = new KeyValue[kvs1.length+kvs2.length];
     System.arraycopy(kvs1, 0, kvs, 0, kvs1.length);
     System.arraycopy(kvs2, 0, kvs, kvs1.length, kvs2.length);
 
     Arrays.sort(kvs, KeyValue.COMPARATOR);
 
     Result r = Result.create(kvs);
     for (int i = 0; i < 100; ++i) {
       final byte[] qf = Bytes.toBytes(i);
 
       List<Cell> ks = r.getColumnCells(family, qf);
       assertEquals(2, ks.size());
       assertTrue(CellUtil.matchingQualifier(ks.get(0), qf));
       assertEquals(200, ks.get(0).getTimestamp());
       assertEquals(ks.get(0), r.getColumnLatestCell(family, qf));
     }
   }
 
   public void testBasicGetValue() throws Exception {
     KeyValue [] kvs = genKVs(row, family, value, 1, 100);
 
     Arrays.sort(kvs, KeyValue.COMPARATOR);
 
     Result r = Result.create(kvs);
 
     for (int i = 0; i < 100; ++i) {
       final byte[] qf = Bytes.toBytes(i);
 
       assertByteEquals(Bytes.add(value, Bytes.toBytes(i)), r.getValue(family, qf));
       assertTrue(r.containsColumn(family, qf));
     }
   }
 
   public void testMultiVersionGetValue() throws Exception {
     KeyValue [] kvs1 = genKVs(row, family, value, 1, 100);
     KeyValue [] kvs2 = genKVs(row, family, value, 200, 100);
 
     KeyValue [] kvs = new KeyValue[kvs1.length+kvs2.length];
     System.arraycopy(kvs1, 0, kvs, 0, kvs1.length);
     System.arraycopy(kvs2, 0, kvs, kvs1.length, kvs2.length);
 
     Arrays.sort(kvs, KeyValue.COMPARATOR);
 
     Result r = Result.create(kvs);
     for (int i = 0; i < 100; ++i) {
       final byte[] qf = Bytes.toBytes(i);
 
       assertByteEquals(Bytes.add(value, Bytes.toBytes(i)), r.getValue(family, qf));
       assertTrue(r.containsColumn(family, qf));
     }
   }
 
   public void testBasicLoadValue() throws Exception {
     KeyValue [] kvs = genKVs(row, family, value, 1, 100);
 
     Arrays.sort(kvs, KeyValue.COMPARATOR);
 
     Result r = Result.create(kvs);
     ByteBuffer loadValueBuffer = ByteBuffer.allocate(1024);
 
     for (int i = 0; i < 100; ++i) {
       final byte[] qf = Bytes.toBytes(i);
 
       loadValueBuffer.clear();
       r.loadValue(family, qf, loadValueBuffer);
       loadValueBuffer.flip();
       assertEquals(ByteBuffer.wrap(Bytes.add(value, Bytes.toBytes(i))), loadValueBuffer);
       assertEquals(ByteBuffer.wrap(Bytes.add(value, Bytes.toBytes(i))),
           r.getValueAsByteBuffer(family, qf));
     }
   }
 
   public void testMultiVersionLoadValue() throws Exception {
     KeyValue [] kvs1 = genKVs(row, family, value, 1, 100);
     KeyValue [] kvs2 = genKVs(row, family, value, 200, 100);
 
     KeyValue [] kvs = new KeyValue[kvs1.length+kvs2.length];
     System.arraycopy(kvs1, 0, kvs, 0, kvs1.length);
     System.arraycopy(kvs2, 0, kvs, kvs1.length, kvs2.length);
 
     Arrays.sort(kvs, KeyValue.COMPARATOR);
 
     ByteBuffer loadValueBuffer = ByteBuffer.allocate(1024);
 
     Result r = Result.create(kvs);
     for (int i = 0; i < 100; ++i) {
       final byte[] qf = Bytes.toBytes(i);
 
       loadValueBuffer.clear();
       r.loadValue(family, qf, loadValueBuffer);
       loadValueBuffer.flip();
       assertEquals(ByteBuffer.wrap(Bytes.add(value, Bytes.toBytes(i))), loadValueBuffer);
       assertEquals(ByteBuffer.wrap(Bytes.add(value, Bytes.toBytes(i))),
           r.getValueAsByteBuffer(family, qf));
     }
   }
 
   /**
    * Verify that Result.compareResults(...) behaves correctly.
    */
   public void testCompareResults() throws Exception {
     byte [] value1 = Bytes.toBytes("value1");
     byte [] qual = Bytes.toBytes("qual");
 
     KeyValue kv1 = new KeyValue(row, family, qual, value);
     KeyValue kv2 = new KeyValue(row, family, qual, value1);
 
     Result r1 = Result.create(new KeyValue[] {kv1});
     Result r2 = Result.create(new KeyValue[] {kv2});
     // no exception thrown
     Result.compareResults(r1, r1);
     try {
       // these are different (HBASE-4800)
       Result.compareResults(r1, r2);
       fail();
     } catch (Exception x) {
       assertTrue(x.getMessage().startsWith("This result was different:"));
     }
   }
 
   /**
    * Verifies that one can't modify instance of EMPTY_RESULT.
    */
   public void testEmptyResultIsReadonly() {
     Result emptyResult = Result.EMPTY_RESULT;
     Result otherResult = new Result();
 
     try {
       emptyResult.copyFrom(otherResult);
       fail("UnsupportedOperationException should have been thrown!");
     } catch (UnsupportedOperationException ex) {
       LOG.debug("As expected: " + ex.getMessage());
     }
     try {
       emptyResult.addResults(ClientProtos.RegionLoadStats.getDefaultInstance());
       fail("UnsupportedOperationException should have been thrown!");
     } catch (UnsupportedOperationException ex) {
       LOG.debug("As expected: " + ex.getMessage());
     }
     try {
       emptyResult.setExists(true);
       fail("UnsupportedOperationException should have been thrown!");
     } catch (UnsupportedOperationException ex) {
       LOG.debug("As expected: " + ex.getMessage());
     }
   }
 
   /**
    * Microbenchmark that compares {@link Result#getValue} and {@link Result#loadValue} performance.
    *
    * @throws Exception
    */
   public void doReadBenchmark() throws Exception {
 
     final int n = 5;
     final int m = 100000000;
 
     StringBuilder valueSB = new StringBuilder();
     for (int i = 0; i < 100; i++) {
       valueSB.append((byte)(Math.random() * 10));
     }
 
     StringBuilder rowSB = new StringBuilder();
     for (int i = 0; i < 50; i++) {
       rowSB.append((byte)(Math.random() * 10));
     }
 
     KeyValue [] kvs = genKVs(Bytes.toBytes(rowSB.toString()), family,
         Bytes.toBytes(valueSB.toString()), 1, n);
     Arrays.sort(kvs, KeyValue.COMPARATOR);
     ByteBuffer loadValueBuffer = ByteBuffer.allocate(1024);
     Result r = Result.create(kvs);
 
     byte[][] qfs = new byte[n][Bytes.SIZEOF_INT];
     for (int i = 0; i < n; ++i) {
       System.arraycopy(qfs[i], 0, Bytes.toBytes(i), 0, Bytes.SIZEOF_INT);
     }
 
     // warm up
     for (int k = 0; k < 100000; k++) {
       for (int i = 0; i < n; ++i) {
         r.getValue(family, qfs[i]);
         loadValueBuffer.clear();
         r.loadValue(family, qfs[i], loadValueBuffer);
         loadValueBuffer.flip();
       }
     }
 
     System.gc();
     long start = System.nanoTime();
     for (int k = 0; k < m; k++) {
       for (int i = 0; i < n; ++i) {
         loadValueBuffer.clear();
         r.loadValue(family, qfs[i], loadValueBuffer);
         loadValueBuffer.flip();
       }
     }
     long stop = System.nanoTime();
     System.out.println("loadValue(): " + (stop - start));
 
     System.gc();
     start = System.nanoTime();
     for (int k = 0; k < m; k++) {
       for (int i = 0; i < n; i++) {
         r.getValue(family, qfs[i]);
       }
     }
     stop = System.nanoTime();
     System.out.println("getValue():  " + (stop - start));
   }
 
   /**
    * Calls non-functional test methods.
    *
    * @param args
    */
   public static void main(String[] args) {
     TestResult testResult = new TestResult();
     try {
       testResult.doReadBenchmark();
     } catch (Exception e) {
       LOG.error("Unexpected exception", e);
     }
   }
 }