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/**************************************************************************
/* This class implements a pipe.
/*
/* Copyright (c) 2009 by Bernhard Bablok (mail@bablokb.de)
/*
/* This program is free software; you can redistribute it and/or modify
/* it under the terms of the GNU Library General Public License as published
/* by the Free Software Foundation; either version 2 of the License or
/* (at your option) any later version.
/*
/* This program 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 Library General Public License for more details.
/*
/* You should have received a copy of the GNU Library General Public License
/* along with this program; see the file COPYING.LIB. If not, write to
/* the Free Software Foundation Inc., 59 Temple Place - Suite 330,
/* Boston, MA 02111-1307 USA
/**************************************************************************/
package org.im4java.process;
import java.io.OutputStream;
import java.io.InputStream;
import java.io.IOException;
/**
This class implements a pipe. Useful for piping input to a process
or piping output/error from a process to other streams.
<p>You can use the same Pipe-object for both ends of a process-pipeline.
But you cannot use the same Pipe-object as an OutputConsumer and
ErrorConsumer at the same time.</p>
@version $Revision: 1.4 $
@author $Author: bablokb $
*/
public class Pipe implements InputProvider, OutputConsumer, ErrorConsumer {
//////////////////////////////////////////////////////////////////////////////
/**
Default buffer size of the pipe. Currently 64KB.
*/
public static final int BUFFER_SIZE=65536;
//////////////////////////////////////////////////////////////////////////////
/**
The source of data (i.e. this pipe will provide input for a process).
*/
private InputStream iSource;
//////////////////////////////////////////////////////////////////////////////
/**
The sink for data (i.e. this pipe will consume output of a process).
*/
private OutputStream iSink;
//////////////////////////////////////////////////////////////////////////////
/**
Constructor. At least one of the arguments should not be null.
*/
public Pipe(InputStream pSource, OutputStream pSink) {
iSource = pSource;
iSink = pSink;
}
//////////////////////////////////////////////////////////////////////////////
/**
The InputProvider must write the input to the given OutputStream.
*/
public void provideInput(OutputStream pOutputStream) throws IOException {
copyBytes(iSource,pOutputStream);
}
//////////////////////////////////////////////////////////////////////////////
/**
The OutputConsumer must read the output of a process from the given
InputStream.
*/
public void consumeOutput(InputStream pInputStream) throws IOException {
if (iSink != null) {
copyBytes(pInputStream,iSink);
}
}
//////////////////////////////////////////////////////////////////////////////
/**
The ErrorConsumer must read the error of a process from the given
InputStream.
*/
public void consumeError(InputStream pInputStream) throws IOException {
if (iSink != null) {
copyBytes(pInputStream,iSink);
}
}
//////////////////////////////////////////////////////////////////////////////
/**
Copy bytes from an InputStream to an OutputStream.
*/
private void copyBytes(InputStream pIs, OutputStream pOs) throws IOException {
byte[] buffer = new byte[BUFFER_SIZE];
while (true) {
int byteCount = pIs.read(buffer);
if (byteCount == -1) {
break;
}
pOs.write(buffer,0,byteCount);
}
pOs.flush();
}
}
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