/*
* Copyright (c) 2007-2014 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 cascading.scheme.Scheme;
import cascading.tap.SinkMode;
import cascading.tap.TapException;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
/**
* Class Lfs is a {@link cascading.tap.Tap} class that provides access to the Local File System via Hadoop.
* <p/>
* Note that using a Lfs {@link cascading.tap.Tap} instance in a {@link cascading.flow.Flow} will force a portion of not the whole Flow to be executed
* in "local" mode forcing the Flow to execute in the current JVM. Mixing with {@link cascading.tap.hadoop.Dfs} and other Tap
* types is possible, providing a means to implement complex file/data management functions.
* <p/>
* Use {@link cascading.tap.hadoop.Hfs} if you need a Tap instance that inherits the default {@link FileSystem} used by Hadoop.
*/
public class Lfs extends Hfs
{
@ConstructorProperties({"scheme"})
Lfs( Scheme scheme )
{
super( scheme );
}
/**
* Constructor Lfs creates a new Lfs instance.
*
* @param scheme of type Scheme
* @param stringPath of type String
*/
@ConstructorProperties({"scheme", "stringPath"})
public Lfs( Scheme scheme, String stringPath )
{
super( scheme, stringPath );
}
/**
* Constructor Lfs creates a new Lfs instance.
*
* @param scheme of type Scheme
* @param stringPath of type String
* @param sinkMode of type SinkMode
*/
@ConstructorProperties({"scheme", "stringPath", "sinkMode"})
public Lfs( Scheme scheme, String stringPath, SinkMode sinkMode )
{
super( scheme, stringPath, sinkMode );
}
protected void setStringPath( String stringPath )
{
if( stringPath.matches( ".*://.*" ) && !stringPath.startsWith( "file://" ) )
throw new IllegalArgumentException( "uri must use the file scheme" );
super.setStringPath( stringPath );
}
@Override
protected FileSystem getFileSystem( Configuration conf )
{
try
{
return FileSystem.getLocal( conf );
}
catch( IOException exception )
{
throw new TapException( "unable to get handle to get local filesystem", exception );
}
}
}