org.mycore.common.content.streams.MCRBlockingInputStream Maven / Gradle / Ivy
/*
* This file is part of *** M y C o R e ***
* See http://www.mycore.de/ for details.
*
* MyCoRe 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 3 of the License, or
* (at your option) any later version.
*
* MyCoRe 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 MyCoRe. If not, see .
*/
package org.mycore.common.content.streams;
import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;
/**
* This class implements a special kind of BufferedInputStream that blocks
* invocations of the read method until the number of bytes that were requested
* are fully read from the underlying InputStream. In contrast,
* BufferedInputStream does NOT block when the requested number of bytes is not
* available yet.
*
* @see BufferedInputStream
*
* @author Frank Lützenkirchen
* @version $Revision$ $Date$
*/
public class MCRBlockingInputStream extends BufferedInputStream {
/**
* Constructs a new MCRBlockingInputStream, using the default buffer size of
* BufferedInputStreams.
*
* @param in
* the InputStream to read data from
*/
public MCRBlockingInputStream(InputStream in) {
super(in);
}
/**
* Constructs a new MCRBlockingInputStream that uses the given buffer size.
*
* @param in
* the InputStream to read data from
* @param size
* the size of the read buffer to be used
*/
public MCRBlockingInputStream(InputStream in, int size) {
super(in, size);
}
/**
* Reads 'len' bytes from the underlying input stream and writes the bytes
* that have been read to the buffer 'buf', starting at offset 'off' in the
* buffer byte array. In contrast to BufferedInputStream.read(), this method
* blocks the read request until 'len' bytes have been read completely or
* the end of the input stream is reached.
*
* @return the number of bytes read. If the end of the input stream is not
* reached yet, this is always the same as the number of bytes
* requested in the 'len' parameter.
*/
@Override
public int read(byte[] buf, int off, int len) throws IOException {
int total = 0;
int num = 0;
while (len > 0) {
num = super.read(buf, off, len);
if (num == 0) {
continue;
}
if (num == -1) {
break;
}
total += num;
off += num;
len -= num;
}
return total == 0 ? num : total;
}
}