/** * Copyright 2005 The Apache Software Foundation * * Licensed 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.*;import java.util.Random;import junit.framework.TestCase;/** Unit tests for VersionedWritable. */public class TestVersionedWritable extends TestCase {	public TestVersionedWritable(String name) { super(name); }			/** Example class used in test cases below. */	public static class SimpleVersionedWritable extends VersionedWritable {				private static final Random RANDOM = new Random();		int state = RANDOM.nextInt();				private static byte VERSION = 1;		public byte getVersion() { 			return VERSION; 		}						public void write(DataOutput out) throws IOException {			super.write(out); // version.			out.writeInt(state);		}				public void readFields(DataInput in) throws IOException {			super.readFields(in); // version			this.state = in.readInt();		}				public static SimpleVersionedWritable read(DataInput in) throws IOException {			SimpleVersionedWritable result = new SimpleVersionedWritable();			result.readFields(in);			return result;		}				/** Required by test code, below. */		public boolean equals(Object o) {			if (!(o instanceof SimpleVersionedWritable))				return false;			SimpleVersionedWritable other = (SimpleVersionedWritable)o;			return this.state == other.state;		}	}		public static class AdvancedVersionedWritable extends SimpleVersionedWritable {		String shortTestString = "Now is the time for all good men to come to the aid of the Party";		String longTestString = "Four score and twenty years ago. Blah. Blah. Blah. Blah. Blah. Blah. Blah. Blah.";				String compressableTestString = 			"Blah. Blah. Blah. Blah. Blah. Blah. Blah. Blah. Blah. Blah. Blah. Blah. " +			"Blah. Blah. Blah. Blah. Blah. Blah. Blah. Blah. Blah. Blah. Blah. Blah. " +			"Blah. Blah. Blah. Blah. Blah. Blah. Blah. Blah. Blah. Blah. Blah. Blah. " ;		SimpleVersionedWritable containedObject = new SimpleVersionedWritable();		String[] testStringArray = {"The", "Quick", "Brown", "Fox", "Jumped", "Over", "The", "Lazy", "Dog"};		public void write(DataOutput out) throws IOException {			super.write(out);			out.writeUTF(shortTestString); 			WritableUtils.writeString(out,longTestString); 			int comp = WritableUtils.writeCompressedString(out,compressableTestString); 			System.out.println("Compression is " + comp + "%");			containedObject.write(out); // Warning if this is a recursive call, you need a null value.			WritableUtils.writeStringArray(out,testStringArray); 		}						public void readFields(DataInput in) throws IOException {			super.readFields(in);			shortTestString = in.readUTF();			longTestString = WritableUtils.readString(in); 			compressableTestString = WritableUtils.readCompressedString(in);			containedObject.readFields(in); // Warning if this is a recursive call, you need a null value.			testStringArray = WritableUtils.readStringArray(in); 		}					public boolean equals(Object o) {			super.equals(o);			if (!shortTestString.equals(((AdvancedVersionedWritable)o).shortTestString)) { return false;}			if (!longTestString.equals(((AdvancedVersionedWritable)o).longTestString)) { return false;}			if (!compressableTestString.equals(((AdvancedVersionedWritable)o).compressableTestString)) { return false;}						if (testStringArray.length != ((AdvancedVersionedWritable)o).testStringArray.length) { return false;}			for(int i=0;i< testStringArray.length;i++){				if (!testStringArray[i].equals(((AdvancedVersionedWritable)o).testStringArray[i])) {					return false;				}			}						if (!containedObject.equals(((AdvancedVersionedWritable)o).containedObject)) { return false;}						return true;		}			}	/* This one checks that version mismatch is thrown... */	public static class SimpleVersionedWritableV2 extends SimpleVersionedWritable {		static byte VERSION = 2;		public byte getVersion() { 			return VERSION; 		}			}	/** Test 1: Check that SimpleVersionedWritable. */	public void testSimpleVersionedWritable() throws Exception {		TestWritable.testWritable(new SimpleVersionedWritable());	}	/** Test 2: Check that AdvancedVersionedWritable Works (well, why wouldn't it!). */	public void testAdvancedVersionedWritable() throws Exception {		TestWritable.testWritable(new AdvancedVersionedWritable());	}	/** Test 3: Check that SimpleVersionedWritable throws an Exception. */	public void testSimpleVersionedWritableMismatch() throws Exception {		TestVersionedWritable.testVersionedWritable(new SimpleVersionedWritable(), new SimpleVersionedWritableV2());	}	  /** Utility method for testing VersionedWritables. */  public static void testVersionedWritable(Writable before, Writable after) throws Exception {      DataOutputBuffer dob = new DataOutputBuffer();      before.write(dob);	      DataInputBuffer dib = new DataInputBuffer();      dib.reset(dob.getData(), dob.getLength());      try {          after.readFields(dib);      } catch (VersionMismatchException vmme) {          System.out.println("Good, we expected this:" + vmme);          return;      }	      throw new Exception("A Version Mismatch Didn't Happen!");  }}