com.gc.iotools.stream.is.TeeInputStreamOutputStream Maven / Gradle / Ivy
package com.gc.iotools.stream.is;
/*
* Copyright (c) 2008,2009 Davide Simonetti.
* This source code is released under the BSD Software License.
*/
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import com.gc.iotools.stream.base.AbstractInputStreamWrapper;
/**
*
* Copies the data from the underlying InputStream to the
* OutputStream passed in the constructor. The data copied are
* similar to the underlying InputStream.
*
*
* When the method {@link #close()} is invoked all the bytes
* remaining in the underlying InputStream are copied to the
* OutputStream. This behavior is different from this class and
* {@code TeeInputStream} in Apache commons-io.
*
*
* Bytes skipped are copied to the OutputStream.
*
*
* Sample usage:
*
*
*
* InputStream source=... //some data to be readed.
* ByteArrayOutputStream destination1= new ByteArrayOutputStream();
* ByteArrayOutputStream destination2= new ByteArrayOutputStream();
*
* TeeInputStreamOutputStream tee=
* new TeeInputStreamOutputStream(source,destination1);
* org.apache.commons.io.IOUtils.copy(tee,destination2);
* tee.close();
* //at this point both destination1 and destination2 contains the same bytes.
* byte[] bytes=destination1.getBytes();
*
*
* @see org.apache.commons.io.input.TeeInputStream
* @author dvd.smnt
* @since 1.0.6
*/
public class TeeInputStreamOutputStream extends AbstractInputStreamWrapper {
/**
* Buffer size used in skip() operations.
*/
private static final int BUF_SIZE = 8192;
private long markPosition = 0;
private long destinationPosition = 0;
private long sourcePosition = 0;
/**
* The destination OutputStream where data is written.
*/
protected final OutputStream destination;
/**
* If true source and destination
* streams are closed when {@link #close()} is invoked.
*/
protected final boolean closeStreams;
/**
*
* Creates a TeeInputStreamOutputStream and saves its argument,
* the input stream source and the OutputStream
* destination for later use.
*
*
* When the method {@link #close()} it is invoked the remaining content of
* the source stream is copied to the destination
* and the source and destination streams are
* closed.
*
*
* @param source
* The underlying InputStream
* @param destination
* Data read from source are also written to this
* OutputStream.
*/
public TeeInputStreamOutputStream(final InputStream source,
final OutputStream destination) {
this(source, destination, true);
}
/**
* Creates a TeeInputStreamOutputStream and saves its argument,
* the input stream source and the output stream
* destination for later use.
*
* @since 1.2.0
* @param source
* The underlying InputStream
* @param destination
* Data read from source are also written to this
* OutputStream.
* @param closeStreams
* if true the destination will be
* closed when the {@link #close()} method is invoked. If
* false the close method on the underlying streams
* will not be called (it must be invoked externally).
*
*/
public TeeInputStreamOutputStream(final InputStream source,
final OutputStream destination, final boolean closeStreams) {
super(source);
this.destination = destination;
this.closeStreams = closeStreams;
}
/**
* {@inheritDoc}
*/
@Override
public int available() throws IOException {
return this.source.available();
}
/**
*
* This method is called when the method {@link #close()} is invoked. It
* copies all the data eventually remaining in the source
* InputStream passed in the constructor to the destination
* OutputStream.
*
*
* The standard behavior is to close both the underlying
* InputStream and OutputStream. When the class
* was constructed with the parameter
* {@link TeeInputStreamOutputStream#closeStreams closeStreams} set to false
* the underlying streams must be closed externally.
*
* @throws IOException
* thrown when a IO problem occurs in reading or writing the
* data.
* @see #close()
*/
@Override
public void closeOnce() throws IOException {
IOException e1 = null;
try {
final byte[] buffer = new byte[BUF_SIZE];
while (innerRead(buffer, 0, BUF_SIZE) > 0) {
// empty block: just throw bytes away
}
} catch (final IOException e) {
e1 = new IOException(
"It's not possible to copy to the destination OutputStream.");
e1.initCause(e);
}
if (this.closeStreams) {
this.source.close();
this.destination.close();
}
if (e1 != null) {
throw e1;
}
}
@Override
public int innerRead(final byte[] b, final int off, final int len)
throws IOException {
final int result = this.source.read(b, off, len);
if (result > 0) {
if (this.sourcePosition + result > this.destinationPosition) {
final int newLen = (int) (this.sourcePosition + result - this.destinationPosition);
final int newOff = off + (result - newLen);
this.destination.write(b, newOff, newLen);
this.destinationPosition += newLen;
}
this.sourcePosition += result;
}
return result;
}
/**
*
* Marks the current position in this input stream. A subsequent call to the
* reset method repositions this stream at the last marked
* position so that subsequent reads re-read the same bytes.
*
*
* @param readLimit
* the maximum limit of bytes that can be read before the mark
* position becomes invalid.
* @see #reset()
* @see java.io.InputStream#mark(int)
* @since 1.2.0
*/
@Override
public void mark(final int readLimit) {
this.source.mark(readLimit);
this.markPosition = this.sourcePosition;
}
/**
* {@inheritDoc}
*/
@Override
public boolean markSupported() {
return this.source.markSupported();
}
/**
* {@inheritDoc}
*/
@Override
public int read() throws IOException {
final int result = this.source.read();
if (result >= 0) {
this.sourcePosition++;
if (this.sourcePosition > this.destinationPosition) {
this.destination.write(result);
this.destinationPosition++;
}
}
return result;
}
/**
*
* Repositions this stream to the position at the time the mark
* method was last called on this input stream.
*
*
* After reset method is called the data is not copied anymore
* to the destination OutputStream until the position where
* reset was issued is reached again. This ensures the data
* copied to the destination OutputStream reflects the data contained in the
* source InputStream (the one passed in the constructor).
*
*
* @see #mark(int)
* @see java.io.InputStream#reset()
* @exception IOException
* If the source stream has an exception in calling reset().
* @since 1.2.0
*/
@Override
public synchronized void reset() throws IOException {
this.source.reset();
this.sourcePosition = this.markPosition;
}
}