cascading.tap.hadoop.Dfs.java Source code

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Here is the source code for cascading.tap.hadoop.Dfs.java

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/*
 * Copyright (c) 2007-2015 Concurrent, Inc. All Rights Reserved.
 *
 * Project and contact information: http://www.cascading.org/
 *
 * This file is part of the Cascading project.
 *
 * 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 cascading.tap.hadoop;

import java.beans.ConstructorProperties;
import java.io.IOException;
import java.net.URI;

import cascading.scheme.Scheme;
import cascading.tap.SinkMode;
import cascading.tap.TapException;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;

/**
 * Class Dfs is a {@link cascading.tap.Tap} class that provides access to the Hadoop Distributed File System.
 * <p/>
 * Use the {@link URI} constructors to specify a different HDFS cluster than the default.
 */
public class Dfs extends Hfs {
    /**
     * Constructor Dfs creates a new Dfs instance.
     *
     * @param scheme of type Scheme
     * @param uri    of type URI
     */
    @ConstructorProperties({ "scheme", "uri" })
    public Dfs(Scheme scheme, URI uri) {
        super(scheme, uri.getPath());

        init(uri);
    }

    /**
     * Constructor Dfs creates a new Dfs instance.
     *
     * @param scheme   of type Scheme
     * @param uri      of type URI
     * @param sinkMode of type SinkMode
     */
    @ConstructorProperties({ "scheme", "uri", "sinkMode" })
    public Dfs(Scheme scheme, URI uri, SinkMode sinkMode) {
        super(scheme, uri.getPath(), sinkMode);

        init(uri);
    }

    /**
     * Constructor Dfs creates a new Dfs instance.
     *
     * @param scheme     of type Scheme
     * @param stringPath of type String
     */
    @ConstructorProperties({ "scheme", "stringPath" })
    public Dfs(Scheme scheme, String stringPath) {
        super(scheme, stringPath);
    }

    /**
     * Constructor Dfs creates a new Dfs instance.
     *
     * @param scheme     of type Scheme
     * @param stringPath of type String
     * @param sinkMode   of type SinkMode
     */
    @ConstructorProperties({ "scheme", "stringPath", "sinkMode" })
    public Dfs(Scheme scheme, String stringPath, SinkMode sinkMode) {
        super(scheme, stringPath, sinkMode);
    }

    private void init(URI uri) {
        if (!uri.getScheme().equalsIgnoreCase("hdfs"))
            throw new IllegalArgumentException("uri must use the hdfs scheme");

        setUriScheme(URI.create(uri.getScheme() + "://" + uri.getAuthority()));
    }

    protected void setStringPath(String stringPath) {
        if (stringPath.matches(".*://.*") && !stringPath.startsWith("hdfs://"))
            throw new IllegalArgumentException("uri must use the hdfs scheme");

        super.setStringPath(stringPath);
    }

    @Override
    protected FileSystem getDefaultFileSystem(Configuration configuration) {
        String name = configuration.get("fs.default.name", "hdfs://localhost:5001/");

        if (name.equals("local") || name.matches(".*://.*") && !name.startsWith("hdfs://"))
            name = "hdfs://localhost:5001/";
        else if (name.indexOf('/') == -1)
            name = "hdfs://" + name;

        try {
            return FileSystem.get(URI.create(name), configuration);
        } catch (IOException exception) {
            throw new TapException("unable to get handle to get filesystem for: " + name, exception);
        }
    }
}