TestWritable.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 java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.util.Random;
import org.apache.hadoop.conf.Configurable;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.util.ReflectionUtils;
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNotNull;
import static org.junit.jupiter.api.Assertions.assertNull;
import static org.junit.jupiter.api.Assertions.assertTrue;
/** Unit tests for Writable. */
public class TestWritable {
private static final String TEST_CONFIG_PARAM = "frob.test";
private static final String TEST_CONFIG_VALUE = "test";
private static final String TEST_WRITABLE_CONFIG_PARAM = "test.writable";
private static final String TEST_WRITABLE_CONFIG_VALUE = TEST_CONFIG_VALUE;
/** Example class used in test cases below. */
public static class SimpleWritable implements Writable {
private static final Random RANDOM = new Random();
int state = RANDOM.nextInt();
@Override
public void write(DataOutput out) throws IOException {
out.writeInt(state);
}
@Override
public void readFields(DataInput in) throws IOException {
this.state = in.readInt();
}
public static SimpleWritable read(DataInput in) throws IOException {
SimpleWritable result = new SimpleWritable();
result.readFields(in);
return result;
}
/** Required by test code, below. */
@Override
public boolean equals(Object o) {
if (!(o instanceof SimpleWritable))
return false;
SimpleWritable other = (SimpleWritable)o;
return this.state == other.state;
}
}
public static class SimpleWritableComparable extends SimpleWritable
implements WritableComparable<SimpleWritableComparable>, Configurable {
private Configuration conf;
public SimpleWritableComparable() {}
public void setConf(Configuration conf) {
this.conf = conf;
}
public Configuration getConf() {
return this.conf;
}
public int compareTo(SimpleWritableComparable o) {
return this.state - o.state;
}
}
/** Test 1: Check that SimpleWritable. */
@Test
public void testSimpleWritable() throws Exception {
testWritable(new SimpleWritable());
}
@Test
public void testByteWritable() throws Exception {
testWritable(new ByteWritable((byte)128));
}
@Test
public void testShortWritable() throws Exception {
testWritable(new ShortWritable((byte)256));
}
@Test
public void testDoubleWritable() throws Exception {
testWritable(new DoubleWritable(1.0));
}
/** Utility method for testing writables. */
public static Writable testWritable(Writable before)
throws Exception {
return testWritable(before, null);
}
/** Utility method for testing writables. */
public static Writable testWritable(Writable before
, Configuration conf) throws Exception {
DataOutputBuffer dob = new DataOutputBuffer();
before.write(dob);
DataInputBuffer dib = new DataInputBuffer();
dib.reset(dob.getData(), dob.getLength());
Writable after = (Writable)ReflectionUtils.newInstance(
before.getClass(), conf);
after.readFields(dib);
assertEquals(before, after);
return after;
}
private static class FrobComparator extends WritableComparator {
public FrobComparator() { super(Frob.class); }
@Override public int compare(byte[] b1, int s1, int l1,
byte[] b2, int s2, int l2) {
return 0;
}
}
private static class Frob implements WritableComparable<Frob> {
static { // register default comparator
WritableComparator.define(Frob.class, new FrobComparator());
}
@Override public void write(DataOutput out) throws IOException {}
@Override public void readFields(DataInput in) throws IOException {}
@Override public int compareTo(Frob o) { return 0; }
}
/** Test that comparator is defined and configured. */
public static void testGetComparator() throws Exception {
Configuration conf = new Configuration();
// Without conf.
WritableComparator frobComparator = WritableComparator.get(Frob.class);
assert(frobComparator instanceof FrobComparator);
assertNotNull(frobComparator.getConf());
assertNull(frobComparator.getConf().get(TEST_CONFIG_PARAM));
// With conf.
conf.set(TEST_CONFIG_PARAM, TEST_CONFIG_VALUE);
frobComparator = WritableComparator.get(Frob.class, conf);
assert(frobComparator instanceof FrobComparator);
assertNotNull(frobComparator.getConf());
assertEquals(conf.get(TEST_CONFIG_PARAM), TEST_CONFIG_VALUE);
// Without conf. should reuse configuration.
frobComparator = WritableComparator.get(Frob.class);
assert(frobComparator instanceof FrobComparator);
assertNotNull(frobComparator.getConf());
assertEquals(conf.get(TEST_CONFIG_PARAM), TEST_CONFIG_VALUE);
// New conf. should use new configuration.
frobComparator = WritableComparator.get(Frob.class, new Configuration());
assert(frobComparator instanceof FrobComparator);
assertNotNull(frobComparator.getConf());
assertNull(frobComparator.getConf().get(TEST_CONFIG_PARAM));
}
/**
* Test a user comparator that relies on deserializing both arguments for each
* compare.
*/
@Test
public void testShortWritableComparator() throws Exception {
ShortWritable writable1 = new ShortWritable((short)256);
ShortWritable writable2 = new ShortWritable((short) 128);
ShortWritable writable3 = new ShortWritable((short) 256);
final String SHOULD_NOT_MATCH_WITH_RESULT_ONE = "Result should be 1, should not match the writables";
assertTrue(writable1.compareTo(writable2) == 1,
SHOULD_NOT_MATCH_WITH_RESULT_ONE);
assertTrue(WritableComparator.get(
ShortWritable.class).compare(writable1, writable2) == 1,
SHOULD_NOT_MATCH_WITH_RESULT_ONE);
final String SHOULD_NOT_MATCH_WITH_RESULT_MINUS_ONE = "Result should be -1, should not match the writables";
assertTrue(writable2.compareTo(writable1) == -1,
SHOULD_NOT_MATCH_WITH_RESULT_MINUS_ONE);
assertTrue(WritableComparator.get(
ShortWritable.class).compare(writable2, writable1) == -1,
SHOULD_NOT_MATCH_WITH_RESULT_MINUS_ONE);
final String SHOULD_MATCH = "Result should be 0, should match the writables";
assertTrue(writable1.compareTo(writable1) == 0, SHOULD_MATCH);
assertTrue(WritableComparator.get(ShortWritable.class)
.compare(writable1, writable3) == 0, SHOULD_MATCH);
}
/**
* Test that Writable's are configured by Comparator.
*/
@Test
public void testConfigurableWritableComparator() throws Exception {
Configuration conf = new Configuration();
conf.set(TEST_WRITABLE_CONFIG_PARAM, TEST_WRITABLE_CONFIG_VALUE);
WritableComparator wc = WritableComparator.get(SimpleWritableComparable.class, conf);
SimpleWritableComparable key = ((SimpleWritableComparable)wc.newKey());
assertNotNull(wc.getConf());
assertNotNull(key.getConf());
assertEquals(key.getConf().get(TEST_WRITABLE_CONFIG_PARAM), TEST_WRITABLE_CONFIG_VALUE);
}
}