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  @Test
050  public void testBasics() throws Exception {
051    int included = 0;
052    int max = 1000000;
053    for (int i = 0; i < max; i++) {
054      if (!quarterChanceFilter.filterRowKey(KeyValueUtil.createFirstOnRow(Bytes.toBytes("row")))) {
055        included++;
056      }
057    }
058    // Now let's check if the filter included the right number of rows;
059    // since we're dealing with randomness, we must have a include an epsilon
060    // tolerance.
061    int epsilon = max / 100;
062    assertTrue("Roughly 25% should pass the filter", Math.abs(included - max / 4) < epsilon);
063  }
064
065  /**
066   * Tests serialization
067   */
068  @Test
069  public void testSerialization() throws Exception {
070    RandomRowFilter newFilter = serializationTest(quarterChanceFilter);
071    // use epsilon float comparison
072    assertTrue("float should be equal",
073      Math.abs(newFilter.getChance() - quarterChanceFilter.getChance()) < 0.000001f);
074  }
075
076  private RandomRowFilter serializationTest(RandomRowFilter filter) throws Exception {
077    // Decompose filter to bytes.
078    byte[] buffer = filter.toByteArray();
079
080    // Recompose filter.
081    RandomRowFilter newFilter = RandomRowFilter.parseFrom(buffer);
082
083    return newFilter;
084  }
085
086}