TestFileChannel.java

/*
 * Copyright 2016 Damien Carol <damien.carol@gmail.com>
 *
 * 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 hdfs.jsr203;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.URI;
import java.nio.channels.Channels;
import java.nio.channels.FileChannel;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileUtil;
import org.apache.hadoop.hdfs.MiniDFSCluster;
import org.junit.AfterClass;
import org.junit.Assert;
import org.junit.BeforeClass;
import org.junit.Test;

public class TestFileChannel extends TestHadoop {

    private static MiniDFSCluster cluster;
    private static URI clusterUri;

    @BeforeClass
    public static void setUpBeforeClass() throws Exception {
        cluster = startMini(TestFileChannel.class.getName());
        clusterUri = formalizeClusterURI(cluster.getFileSystem().getUri());
    }

    @AfterClass
    public static void teardownClass() throws Exception {
        if (cluster != null) {
            cluster.shutdown();
        }
    }

    private static MiniDFSCluster startMini(String testName) throws IOException {
        File baseDir = new File("./target/hdfs/" + testName).getAbsoluteFile();
        FileUtil.fullyDelete(baseDir);
        Configuration conf = new Configuration();
        conf.set(MiniDFSCluster.HDFS_MINIDFS_BASEDIR, baseDir.getAbsolutePath());
        MiniDFSCluster.Builder builder = new MiniDFSCluster.Builder(conf);
        MiniDFSCluster hdfsCluster = builder.clusterId(testName).build();
        hdfsCluster.waitActive();
        return hdfsCluster;
    }
    
    @Test
    public void open() throws IOException {
        Path rootPath = Paths.get(clusterUri);
        Path path = Files.createTempFile(rootPath, "test", "tmp");
        FileChannel ch = FileChannel.open(path);
        InputStream input = Channels.newInputStream(ch);
        Assert.assertEquals(0, input.available());
        ch.close();
    }

}