JavaTM 2 Platform Std. Ed. v1.6.0
java.lang
Class Process
java.lang.Object
java.lang.Process
public abstract class Process - extends Object
The ProcessBuilder.start() and
Runtime.exec
methods create a native process and
return an instance of a subclass of Process that can
be used to control the process and obtain information about it.
The class Process provides methods for performing
input from the process, performing output to the process, waiting
for the process to complete, checking the exit status of the process,
and destroying (killing) the process.
The methods that create processes may not work well for special
processes on certain native platforms, such as native windowing
processes, daemon processes, Win16/DOS processes on Microsoft Windows, or shell
scripts. The created subprocess does not have its own terminal or
console. All its standard io (i.e. stdin, stdout, stderr) operations
will be redirected to the parent process through three streams
(getOutputStream() ,
getInputStream() ,
getErrorStream() ).
The parent process uses these streams to feed input to and get output
from the subprocess. Because some native platforms only provide
limited buffer size for standard input and output streams, failure
to promptly write the input stream or read the output stream of
the subprocess may cause the subprocess to block, and even deadlock.
The subprocess is not killed when there are no more references to
the Process object, but rather the subprocess
continues executing asynchronously.
There is no requirement that a process represented by a Process
object execute asynchronously or concurrently with respect to the Java
process that owns the Process object.
- Since:
- JDK1.0
- See Also:
ProcessBuilder ,
Runtime.exec(String[], String[], File)
Method Summary |
abstract void |
destroy()
Kills the subprocess. |
abstract int |
exitValue()
Returns the exit value for the subprocess. |
abstract InputStream |
getErrorStream()
Gets the error stream of the subprocess. |
abstract InputStream |
getInputStream()
Gets the input stream of the subprocess. |
abstract OutputStream |
getOutputStream()
Gets the output stream of the subprocess. |
abstract int |
waitFor()
causes the current thread to wait, if necessary, until the
process represented by this Process object has
terminated. |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Process
public Process()
getOutputStream
public abstract OutputStream getOutputStream()
- Gets the output stream of the subprocess.
Output to the stream is piped into the standard input stream of
the process represented by this
Process object.
Implementation note: It is a good idea for the output stream to
be buffered.
- Returns:
- the output stream connected to the normal input of the
subprocess.
getInputStream
public abstract InputStream getInputStream()
- Gets the input stream of the subprocess.
The stream obtains data piped from the standard output stream
of the process represented by this
Process object.
Implementation note: It is a good idea for the input stream to
be buffered.
- Returns:
- the input stream connected to the normal output of the
subprocess.
- See Also:
ProcessBuilder.redirectErrorStream()
getErrorStream
public abstract InputStream getErrorStream()
- Gets the error stream of the subprocess.
The stream obtains data piped from the error output stream of the
process represented by this
Process object.
Implementation note: It is a good idea for the input stream to be
buffered.
- Returns:
- the input stream connected to the error stream of the
subprocess.
- See Also:
ProcessBuilder.redirectErrorStream()
waitFor
public abstract int waitFor()
throws InterruptedException
- causes the current thread to wait, if necessary, until the
process represented by this
Process object has
terminated. This method returns
immediately if the subprocess has already terminated. If the
subprocess has not yet terminated, the calling thread will be
blocked until the subprocess exits.
- Returns:
- the exit value of the process. By convention,
0 indicates normal termination.
- Throws:
InterruptedException - if the current thread is
interrupted by another
thread while it is waiting, then the wait is ended and
an InterruptedException is thrown.
exitValue
public abstract int exitValue()
- Returns the exit value for the subprocess.
- Returns:
- the exit value of the subprocess represented by this
Process object. by convention, the value
0 indicates normal termination.
- Throws:
IllegalThreadStateException - if the subprocess represented
by this Process object has not yet terminated.
destroy
public abstract void destroy()
- Kills the subprocess. The subprocess represented by this
Process object is forcibly terminated.
Copyright 2003 Sun Microsystems, Inc. All rights reserved
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