/**
* 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.dfs;
import junit.framework.TestCase;
import java.io.*;
import java.util.Random;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSInputStream;
import org.apache.hadoop.fs.FSOutputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
/**
* This class tests the creation of files with block-size
* smaller than the default buffer size of 4K.
* @author Milind Bhandarkar
*/
public class TestSmallBlock extends TestCase {
static final long seed = 0xDEADBEEFL;
static final int blockSize = 1;
static final int fileSize = 20;
private void writeFile(FileSystem fileSys, Path name) throws IOException {
// create and write a file that contains three blocks of data
FSOutputStream stm = fileSys.createRaw(name, true, (short)1,
(long)blockSize);
byte[] buffer = new byte[fileSize];
Random rand = new Random(seed);
rand.nextBytes(buffer);
stm.write(buffer);
stm.close();
}
private void checkAndEraseData(byte[] actual, int from, byte[] expected, String message) {
for (int idx = 0; idx < actual.length; idx++) {
this.assertEquals(message+" byte "+(from+idx)+" differs. expected "+
expected[from+idx]+" actual "+actual[idx],
actual[idx], expected[from+idx]);
actual[idx] = 0;
}
}
private void checkFile(FileSystem fileSys, Path name) throws IOException {
String[][] locations = fileSys.getFileCacheHints(name, 0, fileSize);
assertEquals("Number of blocks", fileSize, locations.length);
FSInputStream stm = fileSys.openRaw(name);
byte[] expected = new byte[fileSize];
Random rand = new Random(seed);
rand.nextBytes(expected);
// do a sanity check. Read the file
byte[] actual = new byte[fileSize];
stm.readFully(0, actual);
checkAndEraseData(actual, 0, expected, "Read Sanity Test");
stm.close();
}
private void cleanupFile(FileSystem fileSys, Path name) throws IOException {
assertTrue(fileSys.exists(name));
fileSys.delete(name);
assertTrue(!fileSys.exists(name));
}
/**
* Tests small block size in in DFS.
*/
public void testSmallBlock() throws IOException {
Configuration conf = new Configuration();
MiniDFSCluster cluster = new MiniDFSCluster(65312, conf, 1, false);
FileSystem fileSys = cluster.getFileSystem();
try {
Path file1 = new Path("smallblocktest.dat");
writeFile(fileSys, file1);
checkFile(fileSys, file1);
cleanupFile(fileSys, file1);
} finally {
fileSys.close();
cluster.shutdown();
}
}
}