src/test/core/org/apache/hadoop/io/TestMapFile.java

/**
 * 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.io;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;

import junit.framework.TestCase;

public class TestMapFile extends TestCase {
  private static Configuration conf = new Configuration();

  /**
   * Test getClosest feature.
   * @throws Exception
   */
  public void testGetClosest() throws Exception {
    // Write a mapfile of simple data: keys are 
    Path dirName = new Path(System.getProperty("test.build.data",".") +
      getName() + ".mapfile"); 
    FileSystem fs = FileSystem.getLocal(conf);
    Path qualifiedDirName = fs.makeQualified(dirName);
    // Make an index entry for every third insertion.
    MapFile.Writer.setIndexInterval(conf, 3);
    MapFile.Writer writer = new MapFile.Writer(conf, fs,
      qualifiedDirName.toString(), Text.class, Text.class);
    // Assert that the index interval is 1
    assertEquals(3, writer.getIndexInterval());
    // Add entries up to 100 in intervals of ten.
    final int FIRST_KEY = 10;
    for (int i = FIRST_KEY; i < 100; i += 10) {
      String iStr = Integer.toString(i);
      Text t = new Text("00".substring(iStr.length()) + iStr);
      writer.append(t, t);
    }
    writer.close();
    // Now do getClosest on created mapfile.
    MapFile.Reader reader = new MapFile.Reader(fs, qualifiedDirName.toString(),
      conf);
    Text key = new Text("55");
    Text value = new Text();
    Text closest = (Text)reader.getClosest(key, value);
    // Assert that closest after 55 is 60
    assertEquals(new Text("60"), closest);
    // Get closest that falls before the passed key: 50
    closest = (Text)reader.getClosest(key, value, true);
    assertEquals(new Text("50"), closest);
    // Test get closest when we pass explicit key
    final Text TWENTY = new Text("20");
    closest = (Text)reader.getClosest(TWENTY, value);
    assertEquals(TWENTY, closest);
    closest = (Text)reader.getClosest(TWENTY, value, true);
    assertEquals(TWENTY, closest);
    // Test what happens at boundaries.  Assert if searching a key that is
    // less than first key in the mapfile, that the first key is returned.
    key = new Text("00");
    closest = (Text)reader.getClosest(key, value);
    assertEquals(FIRST_KEY, Integer.parseInt(closest.toString()));
    
    // If we're looking for the first key before, and we pass in a key before 
    // the first key in the file, we should get null
    closest = (Text)reader.getClosest(key, value, true);
    assertNull(closest);
    
    // Assert that null is returned if key is > last entry in mapfile.
    key = new Text("99");
    closest = (Text)reader.getClosest(key, value);
    assertNull(closest);

    // If we were looking for the key before, we should get the last key
    closest = (Text)reader.getClosest(key, value, true);
    assertEquals(new Text("90"), closest);
  }

  public void testMidKey() throws Exception {
    // Write a mapfile of simple data: keys are 
    Path dirName = new Path(System.getProperty("test.build.data",".") +
      getName() + ".mapfile"); 
    FileSystem fs = FileSystem.getLocal(conf);
    Path qualifiedDirName = fs.makeQualified(dirName);
 
    MapFile.Writer writer = new MapFile.Writer(conf, fs,
      qualifiedDirName.toString(), IntWritable.class, IntWritable.class);
    writer.append(new IntWritable(1), new IntWritable(1));
    writer.close();
    // Now do getClosest on created mapfile.
    MapFile.Reader reader = new MapFile.Reader(fs, qualifiedDirName.toString(),
      conf);
    assertEquals(new IntWritable(1), reader.midKey());
  }


  public void testMidKeyEmpty() throws Exception {
    // Write a mapfile of simple data: keys are 
    Path dirName = new Path(System.getProperty("test.build.data",".") +
      getName() + ".mapfile"); 
    FileSystem fs = FileSystem.getLocal(conf);
    Path qualifiedDirName = fs.makeQualified(dirName);
 
    MapFile.Writer writer = new MapFile.Writer(conf, fs,
      qualifiedDirName.toString(), IntWritable.class, IntWritable.class);
    writer.close();
    // Now do getClosest on created mapfile.
    MapFile.Reader reader = new MapFile.Reader(fs, qualifiedDirName.toString(),
      conf);
    assertEquals(null, reader.midKey());
  }
}