com.datatorrent.contrib.hdht.HDHTFileAccessFSImpl.java Source code

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Here is the source code for com.datatorrent.contrib.hdht.HDHTFileAccessFSImpl.java

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/*
 * Copyright (c) 2014 DataTorrent, Inc. ALL Rights Reserved.
 *
 * 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 com.datatorrent.contrib.hdht;

import java.io.IOException;

import javax.validation.constraints.NotNull;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileContext;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Options.Rename;
import org.apache.hadoop.fs.Path;

import com.datatorrent.common.util.DTThrowable;

/**
 * Hadoop file system backed store.
 *
 * @since 2.0.0
 */
abstract public class HDHTFileAccessFSImpl implements HDHTFileAccess {
    @NotNull
    private String basePath;
    protected transient FileSystem fs;

    public HDHTFileAccessFSImpl() {
    }

    public String getBasePath() {
        return basePath;
    }

    public void setBasePath(String path) {
        this.basePath = path;
    }

    protected Path getFilePath(long bucketKey, String fileName) {
        return new Path(getBucketPath(bucketKey), fileName);
    }

    protected Path getBucketPath(long bucketKey) {
        return new Path(basePath, Long.toString(bucketKey));
    }

    @Override
    public long getFileSize(long bucketKey, String fileName) throws IOException {
        return fs.getFileStatus(getFilePath(bucketKey, fileName)).getLen();
    }

    @Override
    public void close() throws IOException {
        fs.close();
    }

    @Override
    public void init() {
        if (fs == null) {
            Path dataFilePath = new Path(basePath);
            try {
                fs = FileSystem.newInstance(dataFilePath.toUri(), new Configuration());
            } catch (IOException e) {
                DTThrowable.rethrow(e);
            }
        }
    }

    @Override
    public void delete(long bucketKey, String fileName) throws IOException {
        fs.delete(getFilePath(bucketKey, fileName), true);
    }

    @Override
    public FSDataOutputStream getOutputStream(long bucketKey, String fileName) throws IOException {
        Path path = getFilePath(bucketKey, fileName);
        return fs.create(path, true);
    }

    @Override
    public FSDataInputStream getInputStream(long bucketKey, String fileName) throws IOException {
        return fs.open(getFilePath(bucketKey, fileName));
    }

    @Override
    public void rename(long bucketKey, String fromName, String toName) throws IOException {
        FileContext fc = FileContext.getFileContext(fs.getUri());
        Path bucketPath = getBucketPath(bucketKey);
        // file context requires absolute path
        if (!bucketPath.isAbsolute()) {
            bucketPath = new Path(fs.getWorkingDirectory(), bucketPath);
        }
        fc.rename(new Path(bucketPath, fromName), new Path(bucketPath, toName), Rename.OVERWRITE);
    }

    @Override
    public String toString() {
        return this.getClass().getSimpleName() + "[basePath=" + basePath + "]";
    }

}