org.apache.tools.ant.util.LineOrientedOutputStream Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package org.apache.tools.ant.util;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
/**
* Invokes {@link #processLine processLine} whenever a full line has
* been written to this stream.
*
* Tries to be smart about line separators.
*/
public abstract class LineOrientedOutputStream extends OutputStream {
/** Initial buffer size. */
private static final int INITIAL_SIZE = 132;
/** Carriage return */
private static final int CR = 0x0d;
/** Linefeed */
private static final int LF = 0x0a;
private ByteArrayOutputStream buffer
= new ByteArrayOutputStream(INITIAL_SIZE);
private boolean skip = false;
/**
* Write the data to the buffer and flush the buffer, if a line
* separator is detected.
*
* @param cc data to log (byte).
* @throws IOException if there is an error.
*/
@Override
public final void write(int cc) throws IOException {
final byte c = (byte) cc;
if ((c == LF) || (c == CR)) {
if (!skip) {
processBuffer();
}
} else {
buffer.write(cc);
}
skip = (c == CR);
}
/**
* Flush this log stream
* @throws IOException if there is an error.
*/
@Override
public void flush() throws IOException {
}
/**
* Converts the buffer to a byte[] and sends it to
* processLine
* @throws IOException if there is an error.
*/
protected void processBuffer() throws IOException {
try {
processLine(buffer.toByteArray());
} finally {
buffer.reset();
}
}
/**
* Processes a line.
*
* @param line the line to log.
* @throws IOException if there is an error.
*/
protected abstract void processLine(String line) throws IOException;
/**
* Processes a line.
*
* This implementations invokes the string-arg version
* converting the byte array using the default encoding.
* Subclasses are encouraged to override this method (and provide
* a dummy implementation of the String-arg version) so they don't
* interfere with the encoding of the underlying stream.
*
* @param line the line to log.
* @throws IOException if there is an error.
* @since Ant 1.8.3
*/
protected void processLine(byte[] line) throws IOException {
processLine(new String(line));
}
/**
* Writes all remaining
* @throws IOException if there is an error.
*/
@Override
public void close() throws IOException {
if (buffer.size() > 0) {
processBuffer();
}
super.close();
}
/**
* Write a block of characters to the output stream
*
* @param b the array containing the data
* @param off the offset into the array where data starts
* @param len the length of block
*
* @throws IOException if the data cannot be written into the stream.
*/
@Override
public final void write(byte[] b, int off, int len) throws IOException {
// find the line breaks and pass other chars through in blocks
int offset = off;
int blockStartOffset = offset;
int remaining = len;
while (remaining > 0) {
while (remaining > 0 && b[offset] != LF && b[offset] != CR) {
offset++;
remaining--;
}
// either end of buffer or a line separator char
int blockLength = offset - blockStartOffset;
if (blockLength > 0) {
buffer.write(b, blockStartOffset, blockLength);
}
while (remaining > 0 && (b[offset] == LF || b[offset] == CR)) {
write(b[offset]);
offset++;
remaining--;
}
blockStartOffset = offset;
}
}
}