mapreduce/src/contrib/streaming/src/java/org/apache/hadoop/streaming/StreamUtil.java - hadoop - Git at Google

 /**
  * 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.streaming;

 import java.text.DecimalFormat;
 import java.io.*;
 import java.net.*;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Enumeration;
 import java.util.Iterator;
 import java.util.List;
 import java.util.jar.*;

 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.fs.FileSystem;
 import org.apache.hadoop.fs.FSDataInputStream;
 import org.apache.hadoop.mapred.FileSplit;
 import org.apache.hadoop.mapred.JobConf;
 import org.apache.hadoop.mapreduce.MRJobConfig;
 import org.apache.hadoop.mapreduce.server.jobtracker.JTConfig;

 /** Utilities not available elsewhere in Hadoop.
  *
  */
 public class StreamUtil {

   private static final Log LOG =
     LogFactory.getLog(StreamUtil.class.getName());

   /** It may seem strange to silently switch behaviour when a String
    * is not a classname; the reason is simplified Usage:<pre>
    * -mapper [classname | program ]
    * instead of the explicit Usage:
    * [-mapper program | -javamapper classname], -mapper and -javamapper are mutually exclusive.
    * (repeat for -reducer, -combiner) </pre>
    */
   public static Class goodClassOrNull(Configuration conf, String className, String defaultPackage) {
     Class clazz = null;
     try {
       clazz = conf.getClassByName(className);
     } catch (ClassNotFoundException cnf) {
     }
     if (clazz == null) {
       if (className.indexOf('.') == -1 && defaultPackage != null) {
         className = defaultPackage + "." + className;
         try {
           clazz = conf.getClassByName(className);
         } catch (ClassNotFoundException cnf) {
         }
       }
     }
     return clazz;
   }

   public static String findInClasspath(String className) {
     return findInClasspath(className, StreamUtil.class.getClassLoader());
   }

   /** @return a jar file path or a base directory or null if not found.
    */
   public static String findInClasspath(String className, ClassLoader loader) {

     String relPath = className;
     relPath = relPath.replace('.', '/');
     relPath += ".class";
     java.net.URL classUrl = loader.getResource(relPath);

     String codePath;
     if (classUrl != null) {
       boolean inJar = classUrl.getProtocol().equals("jar");
       codePath = classUrl.toString();
       if (codePath.startsWith("jar:")) {
         codePath = codePath.substring("jar:".length());
       }
       if (codePath.startsWith("file:")) { // can have both
         codePath = codePath.substring("file:".length());
       }
       if (inJar) {
         // A jar spec: remove class suffix in /path/my.jar!/package/Class
         int bang = codePath.lastIndexOf('!');
         codePath = codePath.substring(0, bang);
       } else {
         // A class spec: remove the /my/package/Class.class portion
         int pos = codePath.lastIndexOf(relPath);
         if (pos == -1) {
           throw new IllegalArgumentException("invalid codePath: className=" + className
                                              + " codePath=" + codePath);
         }
         codePath = codePath.substring(0, pos);
       }
     } else {
       codePath = null;
     }
     return codePath;
   }

   // copied from TaskRunner
   static void unJar(File jarFile, File toDir) throws IOException {
     JarFile jar = new JarFile(jarFile);
     try {
       Enumeration entries = jar.entries();
       while (entries.hasMoreElements()) {
         JarEntry entry = (JarEntry) entries.nextElement();
         if (!entry.isDirectory()) {
           InputStream in = jar.getInputStream(entry);
           try {
             File file = new File(toDir, entry.getName());
             boolean b = file.getParentFile().mkdirs();
             if (!b) { LOG.warn("Ignoring failure of mkdirs"); }
             OutputStream out = new FileOutputStream(file);
             try {
               byte[] buffer = new byte[8192];
               int i;
               while ((i = in.read(buffer)) != -1) {
                 out.write(buffer, 0, i);
               }
             } finally {
               out.close();
             }
           } finally {
             in.close();
           }
         }
       }
     } finally {
       jar.close();
     }
   }

   final static long KB = 1024L * 1;
   final static long MB = 1024L * KB;
   final static long GB = 1024L * MB;
   final static long TB = 1024L * GB;
   final static long PB = 1024L * TB;

   static DecimalFormat dfm = new DecimalFormat("####.000");
   static DecimalFormat ifm = new DecimalFormat("###,###,###,###,###");

   public static String dfmt(double d) {
     return dfm.format(d);
   }

   public static String ifmt(double d) {
     return ifm.format(d);
   }

   public static String formatBytes(long numBytes) {
     StringBuffer buf = new StringBuffer();
     boolean bDetails = true;
     double num = numBytes;

     if (numBytes < KB) {
       buf.append(numBytes).append(" B");
       bDetails = false;
     } else if (numBytes < MB) {
       buf.append(dfmt(num / KB)).append(" KB");
     } else if (numBytes < GB) {
       buf.append(dfmt(num / MB)).append(" MB");
     } else if (numBytes < TB) {
       buf.append(dfmt(num / GB)).append(" GB");
     } else if (numBytes < PB) {
       buf.append(dfmt(num / TB)).append(" TB");
     } else {
       buf.append(dfmt(num / PB)).append(" PB");
     }
     if (bDetails) {
       buf.append(" (").append(ifmt(numBytes)).append(" bytes)");
     }
     return buf.toString();
   }

   public static String formatBytes2(long numBytes) {
     StringBuffer buf = new StringBuffer();
     long u = 0;
     if (numBytes >= TB) {
       u = numBytes / TB;
       numBytes -= u * TB;
       buf.append(u).append(" TB ");
     }
     if (numBytes >= GB) {
       u = numBytes / GB;
       numBytes -= u * GB;
       buf.append(u).append(" GB ");
     }
     if (numBytes >= MB) {
       u = numBytes / MB;
       numBytes -= u * MB;
       buf.append(u).append(" MB ");
     }
     if (numBytes >= KB) {
       u = numBytes / KB;
       buf.append(u).append(" KB ");
     }
     buf.append(u).append(" B"); //even if zero
     return buf.toString();
   }

   static Environment env;
   static String HOST;

   static {
     try {
       env = new Environment();
       HOST = env.getHost();
     } catch (IOException io) {
       io.printStackTrace();
     }
   }

   static class StreamConsumer extends Thread {

     StreamConsumer(InputStream in, OutputStream out) {
       this.bin = new LineNumberReader(new BufferedReader(new InputStreamReader(in)));
       if (out != null) {
         this.bout = new DataOutputStream(out);
       }
     }

     public void run() {
       try {
         String line;
         while ((line = bin.readLine()) != null) {
           if (bout != null) {
             bout.writeUTF(line); //writeChars
             bout.writeChar('\n');
           }
         }
         bout.flush();
       } catch (IOException io) {
       }
     }

     LineNumberReader bin;
     DataOutputStream bout;
   }

   static void exec(String arg, PrintStream log) {
     exec(new String[] { arg }, log);
   }

   static void exec(String[] args, PrintStream log) {
     try {
       log.println("Exec: start: " + Arrays.asList(args));
       Process proc = Runtime.getRuntime().exec(args);
       new StreamConsumer(proc.getErrorStream(), log).start();
       new StreamConsumer(proc.getInputStream(), log).start();
       int status = proc.waitFor();
       //if status != 0
       log.println("Exec: status=" + status + ": " + Arrays.asList(args));
     } catch (InterruptedException in) {
       in.printStackTrace();
     } catch (IOException io) {
       io.printStackTrace();
     }
   }

   static String qualifyHost(String url) {
     try {
       return qualifyHost(new URL(url)).toString();
     } catch (IOException io) {
       return url;
     }
   }

   static URL qualifyHost(URL url) {
     try {
       InetAddress a = InetAddress.getByName(url.getHost());
       String qualHost = a.getCanonicalHostName();
       URL q = new URL(url.getProtocol(), qualHost, url.getPort(), url.getFile());
       return q;
     } catch (IOException io) {
       return url;
     }
   }

   static final String regexpSpecials = "[]()?*+|.!^-\\~@";

   public static String regexpEscape(String plain) {
     StringBuffer buf = new StringBuffer();
     char[] ch = plain.toCharArray();
     int csup = ch.length;
     for (int c = 0; c < csup; c++) {
       if (regexpSpecials.indexOf(ch[c]) != -1) {
         buf.append("\\");
       }
       buf.append(ch[c]);
     }
     return buf.toString();
   }

   public static String safeGetCanonicalPath(File f) {
     try {
       String s = f.getCanonicalPath();
       return (s == null) ? f.toString() : s;
     } catch (IOException io) {
       return f.toString();
     }
   }

   static String slurp(File f) throws IOException {
     int len = (int) f.length();
     byte[] buf = new byte[len];
     FileInputStream in = new FileInputStream(f);
     String contents = null;
     try {
       in.read(buf, 0, len);
       contents = new String(buf, "UTF-8");
     } finally {
       in.close();
     }
     return contents;
   }

   static String slurpHadoop(Path p, FileSystem fs) throws IOException {
     int len = (int) fs.getFileStatus(p).getLen();
     byte[] buf = new byte[len];
     FSDataInputStream in = fs.open(p);
     String contents = null;
     try {
       in.readFully(in.getPos(), buf);
       contents = new String(buf, "UTF-8");
     } finally {
       in.close();
     }
     return contents;
   }

   public static String rjustify(String s, int width) {
     if (s == null) s = "null";
     if (width > s.length()) {
       s = getSpace(width - s.length()) + s;
     }
     return s;
   }

   public static String ljustify(String s, int width) {
     if (s == null) s = "null";
     if (width > s.length()) {
       s = s + getSpace(width - s.length());
     }
     return s;
   }

   static char[] space;
   static {
     space = new char[300];
     Arrays.fill(space, '\u0020');
   }

   public static String getSpace(int len) {
     if (len > space.length) {
       space = new char[Math.max(len, 2 * space.length)];
       Arrays.fill(space, '\u0020');
     }
     return new String(space, 0, len);
   }

   static private Environment env_;

   static Environment env() {
     if (env_ != null) {
       return env_;
     }
     try {
       env_ = new Environment();
     } catch (IOException io) {
       io.printStackTrace();
     }
     return env_;
   }

   public static String makeJavaCommand(Class main, String[] argv) {
     ArrayList vargs = new ArrayList();
     File javaHomeBin = new File(System.getProperty("java.home"), "bin");
     File jvm = new File(javaHomeBin, "java");
     vargs.add(jvm.toString());
     // copy parent classpath
     vargs.add("-classpath");
     vargs.add("\"" + System.getProperty("java.class.path") + "\"");

     // add heap-size limit
     vargs.add("-Xmx" + Runtime.getRuntime().maxMemory());

     // Add main class and its arguments
     vargs.add(main.getName());
     for (int i = 0; i < argv.length; i++) {
       vargs.add(argv[i]);
     }
     return collate(vargs, " ");
   }

   public static String collate(Object[] args, String sep) {
     return collate(Arrays.asList(args), sep);
   }

   public static String collate(List args, String sep) {
     StringBuffer buf = new StringBuffer();
     Iterator it = args.iterator();
     while (it.hasNext()) {
       if (buf.length() > 0) {
         buf.append(" ");
       }
       buf.append(it.next());
     }
     return buf.toString();
   }

   // JobConf helpers

   public static FileSplit getCurrentSplit(JobConf job) {
     String path = job.get(MRJobConfig.MAP_INPUT_FILE);
     if (path == null) {
       return null;
     }
     Path p = new Path(path);
     long start = Long.parseLong(job.get(MRJobConfig.MAP_INPUT_START));
     long length = Long.parseLong(job.get(MRJobConfig.MAP_INPUT_PATH));
     return new FileSplit(p, start, length, job);
   }

   static class TaskId {

     boolean mapTask;
     String jobid;
     int taskid;
     int execid;
   }

   public static boolean isLocalJobTracker(JobConf job) {
     return job.get(JTConfig.JT_IPC_ADDRESS, "local").equals("local");
   }

   public static TaskId getTaskInfo(JobConf job) {
     TaskId res = new TaskId();

     String id = job.get(MRJobConfig.TASK_ATTEMPT_ID);
     if (isLocalJobTracker(job)) {
       // it uses difft naming
       res.mapTask = job.getBoolean(MRJobConfig.TASK_ISMAP, true);
       res.jobid = "0";
       res.taskid = 0;
       res.execid = 0;
     } else {
       String[] e = id.split("_");
       res.mapTask = e[3].equals("m");
       res.jobid = e[1] + "_" + e[2];
       res.taskid = Integer.parseInt(e[4]);
       res.execid = Integer.parseInt(e[5]);
     }
     return res;
   }

   public static void touch(File file) throws IOException {
     file = file.getAbsoluteFile();
     FileOutputStream out = new FileOutputStream(file);
     out.close();
     if (!file.exists()) {
       throw new IOException("touch failed: " + file);
     }
   }

   public static boolean isCygwin() {
     String OS = System.getProperty("os.name");
     return (OS.indexOf("Windows") > -1);
   }

   public static String localizeBin(String path) {
     if (isCygwin()) {
       path = "C:/cygwin/" + path;
     }
     return path;
   }

   /** @param name foo where &lt;junit>&lt;sysproperty key="foo" value="${foo}"/>
    * If foo is undefined then Ant sets the unevaluated value.
    * Take this into account when setting defaultVal. */
   public static String getBoundAntProperty(String name, String defaultVal)
   {
     String val = System.getProperty(name);
     if (val != null && val.indexOf("${") >= 0) {
       val = null;
     }
     if (val == null) {
       val = defaultVal;
     }
     return val;
   }

 }
	/**
	* 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.streaming;

	import java.text.DecimalFormat;
	import java.io.*;
	import java.net.*;
	import java.util.ArrayList;
	import java.util.Arrays;
	import java.util.Enumeration;
	import java.util.Iterator;
	import java.util.List;
	import java.util.jar.*;

	import org.apache.commons.logging.Log;
	import org.apache.commons.logging.LogFactory;
	import org.apache.hadoop.conf.Configuration;
	import org.apache.hadoop.fs.Path;
	import org.apache.hadoop.fs.FileSystem;
	import org.apache.hadoop.fs.FSDataInputStream;
	import org.apache.hadoop.mapred.FileSplit;
	import org.apache.hadoop.mapred.JobConf;
	import org.apache.hadoop.mapreduce.MRJobConfig;
	import org.apache.hadoop.mapreduce.server.jobtracker.JTConfig;

	/** Utilities not available elsewhere in Hadoop.
	*
	*/
	public class StreamUtil {

	private static final Log LOG =
	LogFactory.getLog(StreamUtil.class.getName());

	/** It may seem strange to silently switch behaviour when a String
	* is not a classname; the reason is simplified Usage:<pre>
	* -mapper [classname \| program ]
	* instead of the explicit Usage:
	* [-mapper program \| -javamapper classname], -mapper and -javamapper are mutually exclusive.
	* (repeat for -reducer, -combiner) </pre>
	*/
	public static Class goodClassOrNull(Configuration conf, String className, String defaultPackage) {
	Class clazz = null;
	try {
	clazz = conf.getClassByName(className);
	} catch (ClassNotFoundException cnf) {
	}
	if (clazz == null) {
	if (className.indexOf('.') == -1 && defaultPackage != null) {
	className = defaultPackage + "." + className;
	try {
	clazz = conf.getClassByName(className);
	} catch (ClassNotFoundException cnf) {
	}
	}
	}
	return clazz;
	}

	public static String findInClasspath(String className) {
	return findInClasspath(className, StreamUtil.class.getClassLoader());
	}

	/** @return a jar file path or a base directory or null if not found.
	*/
	public static String findInClasspath(String className, ClassLoader loader) {

	String relPath = className;
	relPath = relPath.replace('.', '/');
	relPath += ".class";
	java.net.URL classUrl = loader.getResource(relPath);

	String codePath;
	if (classUrl != null) {
	boolean inJar = classUrl.getProtocol().equals("jar");
	codePath = classUrl.toString();
	if (codePath.startsWith("jar:")) {
	codePath = codePath.substring("jar:".length());
	}
	if (codePath.startsWith("file:")) { // can have both
	codePath = codePath.substring("file:".length());
	}
	if (inJar) {
	// A jar spec: remove class suffix in /path/my.jar!/package/Class
	int bang = codePath.lastIndexOf('!');
	codePath = codePath.substring(0, bang);
	} else {
	// A class spec: remove the /my/package/Class.class portion
	int pos = codePath.lastIndexOf(relPath);
	if (pos == -1) {
	throw new IllegalArgumentException("invalid codePath: className=" + className
	+ " codePath=" + codePath);
	}
	codePath = codePath.substring(0, pos);
	}
	} else {
	codePath = null;
	}
	return codePath;
	}

	// copied from TaskRunner
	static void unJar(File jarFile, File toDir) throws IOException {
	JarFile jar = new JarFile(jarFile);
	try {
	Enumeration entries = jar.entries();
	while (entries.hasMoreElements()) {
	JarEntry entry = (JarEntry) entries.nextElement();
	if (!entry.isDirectory()) {
	InputStream in = jar.getInputStream(entry);
	try {
	File file = new File(toDir, entry.getName());
	boolean b = file.getParentFile().mkdirs();
	if (!b) { LOG.warn("Ignoring failure of mkdirs"); }
	OutputStream out = new FileOutputStream(file);
	try {
	byte[] buffer = new byte[8192];
	int i;
	while ((i = in.read(buffer)) != -1) {
	out.write(buffer, 0, i);
	}
	} finally {
	out.close();
	}
	} finally {
	in.close();
	}
	}
	}
	} finally {
	jar.close();
	}
	}

	final static long KB = 1024L * 1;
	final static long MB = 1024L * KB;
	final static long GB = 1024L * MB;
	final static long TB = 1024L * GB;
	final static long PB = 1024L * TB;

	static DecimalFormat dfm = new DecimalFormat("####.000");
	static DecimalFormat ifm = new DecimalFormat("###,###,###,###,###");

	public static String dfmt(double d) {
	return dfm.format(d);
	}

	public static String ifmt(double d) {
	return ifm.format(d);
	}

	public static String formatBytes(long numBytes) {
	StringBuffer buf = new StringBuffer();
	boolean bDetails = true;
	double num = numBytes;

	if (numBytes < KB) {
	buf.append(numBytes).append(" B");
	bDetails = false;
	} else if (numBytes < MB) {
	buf.append(dfmt(num / KB)).append(" KB");
	} else if (numBytes < GB) {
	buf.append(dfmt(num / MB)).append(" MB");
	} else if (numBytes < TB) {
	buf.append(dfmt(num / GB)).append(" GB");
	} else if (numBytes < PB) {
	buf.append(dfmt(num / TB)).append(" TB");
	} else {
	buf.append(dfmt(num / PB)).append(" PB");
	}
	if (bDetails) {
	buf.append(" (").append(ifmt(numBytes)).append(" bytes)");
	}
	return buf.toString();
	}

	public static String formatBytes2(long numBytes) {
	StringBuffer buf = new StringBuffer();
	long u = 0;
	if (numBytes >= TB) {
	u = numBytes / TB;
	numBytes -= u * TB;
	buf.append(u).append(" TB ");
	}
	if (numBytes >= GB) {
	u = numBytes / GB;
	numBytes -= u * GB;
	buf.append(u).append(" GB ");
	}
	if (numBytes >= MB) {
	u = numBytes / MB;
	numBytes -= u * MB;
	buf.append(u).append(" MB ");
	}
	if (numBytes >= KB) {
	u = numBytes / KB;
	buf.append(u).append(" KB ");
	}
	buf.append(u).append(" B"); //even if zero
	return buf.toString();
	}

	static Environment env;
	static String HOST;

	static {
	try {
	env = new Environment();
	HOST = env.getHost();
	} catch (IOException io) {
	io.printStackTrace();
	}
	}

	static class StreamConsumer extends Thread {

	StreamConsumer(InputStream in, OutputStream out) {
	this.bin = new LineNumberReader(new BufferedReader(new InputStreamReader(in)));
	if (out != null) {
	this.bout = new DataOutputStream(out);
	}
	}

	public void run() {
	try {
	String line;
	while ((line = bin.readLine()) != null) {
	if (bout != null) {
	bout.writeUTF(line); //writeChars
	bout.writeChar('\n');
	}
	}
	bout.flush();
	} catch (IOException io) {
	}
	}

	LineNumberReader bin;
	DataOutputStream bout;
	}

	static void exec(String arg, PrintStream log) {
	exec(new String[] { arg }, log);
	}

	static void exec(String[] args, PrintStream log) {
	try {
	log.println("Exec: start: " + Arrays.asList(args));
	Process proc = Runtime.getRuntime().exec(args);
	new StreamConsumer(proc.getErrorStream(), log).start();
	new StreamConsumer(proc.getInputStream(), log).start();
	int status = proc.waitFor();
	//if status != 0
	log.println("Exec: status=" + status + ": " + Arrays.asList(args));
	} catch (InterruptedException in) {
	in.printStackTrace();
	} catch (IOException io) {
	io.printStackTrace();
	}
	}

	static String qualifyHost(String url) {
	try {
	return qualifyHost(new URL(url)).toString();
	} catch (IOException io) {
	return url;
	}
	}

	static URL qualifyHost(URL url) {
	try {
	InetAddress a = InetAddress.getByName(url.getHost());
	String qualHost = a.getCanonicalHostName();
	URL q = new URL(url.getProtocol(), qualHost, url.getPort(), url.getFile());
	return q;
	} catch (IOException io) {
	return url;
	}
	}

	static final String regexpSpecials = "[]()?*+\|.!^-\\~@";

	public static String regexpEscape(String plain) {
	StringBuffer buf = new StringBuffer();
	char[] ch = plain.toCharArray();
	int csup = ch.length;
	for (int c = 0; c < csup; c++) {
	if (regexpSpecials.indexOf(ch[c]) != -1) {
	buf.append("\\");
	}
	buf.append(ch[c]);
	}
	return buf.toString();
	}

	public static String safeGetCanonicalPath(File f) {
	try {
	String s = f.getCanonicalPath();
	return (s == null) ? f.toString() : s;
	} catch (IOException io) {
	return f.toString();
	}
	}

	static String slurp(File f) throws IOException {
	int len = (int) f.length();
	byte[] buf = new byte[len];
	FileInputStream in = new FileInputStream(f);
	String contents = null;
	try {
	in.read(buf, 0, len);
	contents = new String(buf, "UTF-8");
	} finally {
	in.close();
	}
	return contents;
	}

	static String slurpHadoop(Path p, FileSystem fs) throws IOException {
	int len = (int) fs.getFileStatus(p).getLen();
	byte[] buf = new byte[len];
	FSDataInputStream in = fs.open(p);
	String contents = null;
	try {
	in.readFully(in.getPos(), buf);
	contents = new String(buf, "UTF-8");
	} finally {
	in.close();
	}
	return contents;
	}

	public static String rjustify(String s, int width) {
	if (s == null) s = "null";
	if (width > s.length()) {
	s = getSpace(width - s.length()) + s;
	}
	return s;
	}

	public static String ljustify(String s, int width) {
	if (s == null) s = "null";
	if (width > s.length()) {
	s = s + getSpace(width - s.length());
	}
	return s;
	}

	static char[] space;
	static {
	space = new char[300];
	Arrays.fill(space, '\u0020');
	}

	public static String getSpace(int len) {
	if (len > space.length) {
	space = new char[Math.max(len, 2 * space.length)];
	Arrays.fill(space, '\u0020');
	}
	return new String(space, 0, len);
	}

	static private Environment env_;

	static Environment env() {
	if (env_ != null) {
	return env_;
	}
	try {
	env_ = new Environment();
	} catch (IOException io) {
	io.printStackTrace();
	}
	return env_;
	}

	public static String makeJavaCommand(Class main, String[] argv) {
	ArrayList vargs = new ArrayList();
	File javaHomeBin = new File(System.getProperty("java.home"), "bin");
	File jvm = new File(javaHomeBin, "java");
	vargs.add(jvm.toString());
	// copy parent classpath
	vargs.add("-classpath");
	vargs.add("\"" + System.getProperty("java.class.path") + "\"");

	// add heap-size limit
	vargs.add("-Xmx" + Runtime.getRuntime().maxMemory());

	// Add main class and its arguments
	vargs.add(main.getName());
	for (int i = 0; i < argv.length; i++) {
	vargs.add(argv[i]);
	}
	return collate(vargs, " ");
	}

	public static String collate(Object[] args, String sep) {
	return collate(Arrays.asList(args), sep);
	}

	public static String collate(List args, String sep) {
	StringBuffer buf = new StringBuffer();
	Iterator it = args.iterator();
	while (it.hasNext()) {
	if (buf.length() > 0) {
	buf.append(" ");
	}
	buf.append(it.next());
	}
	return buf.toString();
	}

	// JobConf helpers

	public static FileSplit getCurrentSplit(JobConf job) {
	String path = job.get(MRJobConfig.MAP_INPUT_FILE);
	if (path == null) {
	return null;
	}
	Path p = new Path(path);
	long start = Long.parseLong(job.get(MRJobConfig.MAP_INPUT_START));
	long length = Long.parseLong(job.get(MRJobConfig.MAP_INPUT_PATH));
	return new FileSplit(p, start, length, job);
	}

	static class TaskId {

	boolean mapTask;
	String jobid;
	int taskid;
	int execid;
	}

	public static boolean isLocalJobTracker(JobConf job) {
	return job.get(JTConfig.JT_IPC_ADDRESS, "local").equals("local");
	}

	public static TaskId getTaskInfo(JobConf job) {
	TaskId res = new TaskId();

	String id = job.get(MRJobConfig.TASK_ATTEMPT_ID);
	if (isLocalJobTracker(job)) {
	// it uses difft naming
	res.mapTask = job.getBoolean(MRJobConfig.TASK_ISMAP, true);
	res.jobid = "0";
	res.taskid = 0;
	res.execid = 0;
	} else {
	String[] e = id.split("_");
	res.mapTask = e[3].equals("m");
	res.jobid = e[1] + "_" + e[2];
	res.taskid = Integer.parseInt(e[4]);
	res.execid = Integer.parseInt(e[5]);
	}
	return res;
	}

	public static void touch(File file) throws IOException {
	file = file.getAbsoluteFile();
	FileOutputStream out = new FileOutputStream(file);
	out.close();
	if (!file.exists()) {
	throw new IOException("touch failed: " + file);
	}
	}

	public static boolean isCygwin() {
	String OS = System.getProperty("os.name");
	return (OS.indexOf("Windows") > -1);
	}

	public static String localizeBin(String path) {
	if (isCygwin()) {
	path = "C:/cygwin/" + path;
	}
	return path;
	}

	/** @param name foo where <junit><sysproperty key="foo" value="${foo}"/>
	* If foo is undefined then Ant sets the unevaluated value.
	* Take this into account when setting defaultVal. */
	public static String getBoundAntProperty(String name, String defaultVal)
	{
	String val = System.getProperty(name);
	if (val != null && val.indexOf("${") >= 0) {
	val = null;
	}
	if (val == null) {
	val = defaultVal;
	}
	return val;
	}

	}