001/**
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.apache.hadoop.hbase.filter;
019
020import static org.junit.Assert.*;
021
022import org.apache.hadoop.hbase.HBaseClassTestRule;
023import org.apache.hadoop.hbase.KeyValueUtil;
024import org.apache.hadoop.hbase.testclassification.FilterTests;
025import org.apache.hadoop.hbase.testclassification.SmallTests;
026import org.apache.hadoop.hbase.util.Bytes;
027import org.junit.Before;
028import org.junit.ClassRule;
029import org.junit.Test;
030import org.junit.experimental.categories.Category;
031
032@Category({FilterTests.class, SmallTests.class})
033public class TestRandomRowFilter {
034
035  @ClassRule
036  public static final HBaseClassTestRule CLASS_RULE =
037      HBaseClassTestRule.forClass(TestRandomRowFilter.class);
038
039  protected RandomRowFilter quarterChanceFilter;
040
041  @Before
042  public void setUp() throws Exception {
043    quarterChanceFilter = new RandomRowFilter(0.25f);
044  }
045
046  /**
047   * Tests basics
048   *
049   * @throws Exception
050   */
051  @Test
052  public void testBasics() throws Exception {
053    int included = 0;
054    int max = 1000000;
055    for (int i = 0; i < max; i++) {
056      if (!quarterChanceFilter.filterRowKey(KeyValueUtil.createFirstOnRow(Bytes.toBytes("row")))) {
057        included++;
058      }
059    }
060    // Now let's check if the filter included the right number of rows;
061    // since we're dealing with randomness, we must have a include an epsilon
062    // tolerance.
063    int epsilon = max / 100;
064    assertTrue("Roughly 25% should pass the filter", Math.abs(included - max
065        / 4) < epsilon);
066  }
067
068  /**
069   * Tests serialization
070   *
071   * @throws Exception
072   */
073  @Test
074  public void testSerialization() throws Exception {
075    RandomRowFilter newFilter = serializationTest(quarterChanceFilter);
076    // use epsilon float comparison
077    assertTrue("float should be equal", Math.abs(newFilter.getChance()
078        - quarterChanceFilter.getChance()) < 0.000001f);
079  }
080
081  private RandomRowFilter serializationTest(RandomRowFilter filter)
082      throws Exception {
083    // Decompose filter to bytes.
084    byte[] buffer = filter.toByteArray();
085
086    // Recompose filter.
087    RandomRowFilter newFilter = RandomRowFilter.parseFrom(buffer);
088
089    return newFilter;
090  }
091
092}
093