java.lang

Class Process


public abstract class Process
extends Object

An instance of a subclass of Process is created by the Runtime.exec methods. Methods in Process provide a means to send input to a process, obtain the output from a subprocess, destroy a subprocess, obtain the exit value from a subprocess, and wait for a subprocess to complete.

This is dependent on the platform, and some processes (like native windowing processes, 16-bit processes in Windows, or shell scripts) may be limited in functionality. Because some platforms have limited buffers between processes, you may need to provide input and read output to prevent the process from blocking, or even deadlocking.

Even if all references to this object disapper, the process continues to execute to completion. There are no guarantees that the subprocess execute asynchronously or concurrently with the process which owns this object.

Since:
1.0
See Also:
Runtime.exec(String[],String[],File)

Constructor Summary

Process()
Empty constructor does nothing.

Method Summary

abstract void
destroy()
Kills the subprocess and all of its children forcibly.
abstract int
exitValue()
When a process terminates there is associated with that termination an exit value for the process to indicate why it terminated.
abstract InputStream
getErrorStream()
Obtain the input stream that receives data from the subprocess.
abstract InputStream
getInputStream()
Obtain the input stream that receives data from the subprocess.
abstract OutputStream
getOutputStream()
Obtain the output stream that sends data to the subprocess.
abstract int
waitFor()
The thread calling waitFor will block until the subprocess has terminated.

Methods inherited from class java.lang.Object

clone, equals, extends Object> getClass, finalize, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

Process

public Process()
Empty constructor does nothing.

Method Details

destroy

public abstract void destroy()
Kills the subprocess and all of its children forcibly.

exitValue

public abstract int exitValue()
When a process terminates there is associated with that termination an exit value for the process to indicate why it terminated. A return of 0 denotes normal process termination by convention.
Returns:
the exit value of the subprocess
Throws:
IllegalThreadStateException - if the subprocess has not terminated

getErrorStream

public abstract InputStream getErrorStream()
Obtain the input stream that receives data from the subprocess. This is the STDERR of the subprocess. When implementing, you should probably use a buffered stream.
Returns:
the input stream that pipes data from the process error output

getInputStream

public abstract InputStream getInputStream()
Obtain the input stream that receives data from the subprocess. This is the STDOUT of the subprocess. When implementing, you should probably use a buffered stream.
Returns:
the input stream that pipes data from the process output

getOutputStream

public abstract OutputStream getOutputStream()
Obtain the output stream that sends data to the subprocess. This is the STDIN of the subprocess. When implementing, you should probably use a buffered stream.
Returns:
the output stream that pipes to the process input

waitFor

public abstract int waitFor()
            throws InterruptedException
The thread calling waitFor will block until the subprocess has terminated. If the process has already terminated then the method immediately returns with the exit value of the subprocess.
Returns:
the subprocess exit value; 0 conventionally denotes success
Throws:
InterruptedException - if another thread interrupts the blocked one

Process.java - Represent spawned system process Copyright (C) 1998, 1999, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc. This file is part of GNU Classpath. GNU Classpath is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. GNU Classpath is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GNU Classpath; see the file COPYING. If not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. Linking this library statically or dynamically with other modules is making a combined work based on this library. Thus, the terms and conditions of the GNU General Public License cover the whole combination. As a special exception, the copyright holders of this library give you permission to link this library with independent modules to produce an executable, regardless of the license terms of these independent modules, and to copy and distribute the resulting executable under terms of your choice, provided that you also meet, for each linked independent module, the terms and conditions of the license of that module. An independent module is a module which is not derived from or based on this library. If you modify this library, you may extend this exception to your version of the library, but you are not obligated to do so. If you do not wish to do so, delete this exception statement from your version.