/** * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you 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 org.apache.hadoop.util; import java.io.PrintStream; import org.apache.hadoop.conf.Configuration; /** * A utility to help run {@link Tool}s. * *
ToolRunner
can be used to run classes implementing
* Tool
interface. It works in conjunction with
* {@link GenericOptionsParser} to parse the
*
* generic hadoop command line arguments and modifies the
* Configuration
of the Tool
. The
* application-specific options are passed along without being modified.
*
Tool
by {@link Tool#run(String[])}, after
* parsing with the given generic arguments. Uses the given
* Configuration
, or builds one if null.
*
* Sets the Tool
's configuration with the possibly modified
* version of the conf
.
*
* @param conf Configuration
for the Tool
.
* @param tool Tool
to run.
* @param args command-line arguments to the tool.
* @return exit code of the {@link Tool#run(String[])} method.
*/
public static int run(Configuration conf, Tool tool, String[] args)
throws Exception{
if(conf == null) {
conf = new Configuration();
}
GenericOptionsParser parser = new GenericOptionsParser(conf, args);
//set the configuration back, so that Tool can configure itself
tool.setConf(conf);
//get the args w/o generic hadoop args
String[] toolArgs = parser.getRemainingArgs();
return tool.run(toolArgs);
}
/**
* Runs the Tool
with its Configuration
.
*
* Equivalent to run(tool.getConf(), tool, args)
.
*
* @param tool Tool
to run.
* @param args command-line arguments to the tool.
* @return exit code of the {@link Tool#run(String[])} method.
*/
public static int run(Tool tool, String[] args)
throws Exception{
return run(tool.getConf(), tool, args);
}
/**
* Prints generic command-line argurments and usage information.
*
* @param out stream to write usage information to.
*/
public static void printGenericCommandUsage(PrintStream out) {
GenericOptionsParser.printGenericCommandUsage(out);
}
}