001/* 002 * Copyright (c) 2016-2017 Chris K Wensel <chris@wensel.net>. All Rights Reserved. 003 * Copyright (c) 2007-2017 Xplenty, Inc. All Rights Reserved. 004 * 005 * Project and contact information: http://www.cascading.org/ 006 * 007 * This file is part of the Cascading project. 008 * 009 * Licensed under the Apache License, Version 2.0 (the "License"); 010 * you may not use this file except in compliance with the License. 011 * You may obtain a copy of the License at 012 * 013 * http://www.apache.org/licenses/LICENSE-2.0 014 * 015 * Unless required by applicable law or agreed to in writing, software 016 * distributed under the License is distributed on an "AS IS" BASIS, 017 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 018 * See the License for the specific language governing permissions and 019 * limitations under the License. 020 */ 021 022package cascading.tap.hadoop; 023 024import java.beans.ConstructorProperties; 025import java.io.IOException; 026 027import cascading.scheme.Scheme; 028import cascading.tap.SinkMode; 029import cascading.tap.TapException; 030import org.apache.hadoop.conf.Configuration; 031import org.apache.hadoop.fs.FileSystem; 032 033/** 034 * Class Lfs is a {@link cascading.tap.Tap} class that provides access to the Local File System via Hadoop. 035 * <p> 036 * 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 037 * in "local" mode forcing the Flow to execute in the current JVM. Mixing with {@link cascading.tap.hadoop.Dfs} and other Tap 038 * types is possible, providing a means to implement complex file/data management functions. 039 * <p> 040 * Use {@link cascading.tap.hadoop.Hfs} if you need a Tap instance that inherits the default {@link FileSystem} used by Hadoop. 041 */ 042public class Lfs extends Hfs 043 { 044 @ConstructorProperties({"scheme"}) 045 Lfs( Scheme scheme ) 046 { 047 super( scheme ); 048 } 049 050 /** 051 * Constructor Lfs creates a new Lfs instance. 052 * 053 * @param scheme of type Scheme 054 * @param stringPath of type String 055 */ 056 @ConstructorProperties({"scheme", "stringPath"}) 057 public Lfs( Scheme scheme, String stringPath ) 058 { 059 super( scheme, stringPath ); 060 } 061 062 /** 063 * Constructor Lfs creates a new Lfs instance. 064 * 065 * @param scheme of type Scheme 066 * @param stringPath of type String 067 * @param sinkMode of type SinkMode 068 */ 069 @ConstructorProperties({"scheme", "stringPath", "sinkMode"}) 070 public Lfs( Scheme scheme, String stringPath, SinkMode sinkMode ) 071 { 072 super( scheme, stringPath, sinkMode ); 073 } 074 075 protected void setStringPath( String stringPath ) 076 { 077 if( stringPath.matches( ".*://.*" ) && !stringPath.startsWith( "file://" ) ) 078 throw new IllegalArgumentException( "uri must use the file scheme" ); 079 080 super.setStringPath( stringPath ); 081 } 082 083 @Override 084 protected FileSystem getFileSystem( Configuration conf ) 085 { 086 try 087 { 088 return FileSystem.getLocal( conf ); 089 } 090 catch( IOException exception ) 091 { 092 throw new TapException( "unable to get handle to get local filesystem", exception ); 093 } 094 } 095 }