/*
* 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.sling.scripting.core.impl;
import java.io.Writer;
import org.slf4j.Logger;
/**
* The <code>LogWriter</code> is a simple <code>Writer</code> which writes
* lines of data to a given SLF4J Logger. Data is gathered in an internal buffer
* until the {@link #flush()} method is called or until a CR or LF character is
* encountered in the data to be written.
*/
public class LogWriter extends Writer {
/** The logger to which the error messages are written */
private Logger logger;
/**
* The internal buffer to gather message data until being flushed or a CR or
* LF is encountered in the message data.
*/
private StringBuilder lineBuffer;
/**
* Creates a writer based on the given logger.
*
* @param logger the logger
*/
public LogWriter(Logger logger) {
this.logger = logger;
this.lineBuffer = new StringBuilder();
}
/**
* Writes the character to the internal buffer unless the character is a CR
* or LF in which case the buffer is written to the logger as an error
* message.
*/
@Override
public void write(int c) {
if (c == '\n' || c == '\r') {
flush();
} else {
synchronized (lineBuffer) {
lineBuffer.append((char) c);
}
}
}
/**
* Writes the indicated characters to the internal buffer, flushing the
* buffer on any occurrence of a CR of LF.
*/
@Override
public void write(char[] cbuf, int off, int len) {
int i = off;
for (int n = 0; n < len; n++, i++) {
char c = cbuf[i];
// if CR/LF flush the line
if (c == '\n' || c == '\r') {
// append upto the CR/LF
int subLen = i - off;
if (subLen > 0) {
synchronized (lineBuffer) {
lineBuffer.append(cbuf, off, subLen);
}
}
// and flush
flush();
// new offset is after the CR/LF
off = i + 1;
}
}
// remaining data in the buffer is just appended
if (off < i) {
synchronized (lineBuffer) {
lineBuffer.append(cbuf, off, i - off);
}
}
}
/**
* Writes any data conained in the buffer to the logger as an error message.
*/
@Override
public void flush() {
String message;
synchronized (lineBuffer) {
if (lineBuffer.length() == 0) {
return;
}
message = lineBuffer.toString();
lineBuffer.setLength(0);
}
logger.error(message);
}
/**
* Just calls {@link #flush()}
*/
@Override
public void close() {
flush();
}
}