org.apache.logging.log4j.core.appender.AbstractOutputStreamAppender 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.logging.log4j.core.appender;
import java.io.Serializable;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;
import org.apache.logging.log4j.core.Filter;
import org.apache.logging.log4j.core.Layout;
import org.apache.logging.log4j.core.LogEvent;
/**
* Appends log events as bytes to a byte output stream. The stream encoding is defined in the layout.
*
* @param The kind of {@link OutputStreamManager} under management
*/
public abstract class AbstractOutputStreamAppender extends AbstractAppender {
private static final long serialVersionUID = 1L;
/**
* Immediate flush means that the underlying writer or output stream
* will be flushed at the end of each append operation. Immediate
* flush is slower but ensures that each append request is actually
* written. If immediateFlush is set to
* {@code false}, then there is a good chance that the last few
* logs events are not actually written to persistent media if and
* when the application crashes.
*/
protected final boolean immediateFlush;
private final M manager;
private final ReadWriteLock rwLock = new ReentrantReadWriteLock();
private final Lock readLock = rwLock.readLock();
/**
* Instantiate a WriterAppender and set the output destination to a
* new {@link java.io.OutputStreamWriter} initialized with os
* as its {@link java.io.OutputStream}.
* @param name The name of the Appender.
* @param layout The layout to format the message.
* @param manager The OutputStreamManager.
*/
protected AbstractOutputStreamAppender(final String name, final Layout layout, final Filter filter,
final boolean ignoreExceptions, final boolean immediateFlush,
final M manager) {
super(name, filter, layout, ignoreExceptions);
this.manager = manager;
this.immediateFlush = immediateFlush;
}
/**
* Gets the manager.
*
* @return the manager.
*/
public M getManager() {
return manager;
}
@Override
public void start() {
if (getLayout() == null) {
LOGGER.error("No layout set for the appender named [" + getName() + "].");
}
if (manager == null) {
LOGGER.error("No OutputStreamManager set for the appender named [" + getName() + "].");
}
super.start();
}
@Override
public void stop() {
super.stop();
manager.release();
}
/**
* Actual writing occurs here.
*
* Most subclasses of AbstractOutputStreamAppender will need to override this method.
*
*
* @param event
* The LogEvent.
*/
@Override
public void append(final LogEvent event) {
readLock.lock();
try {
final byte[] bytes = getLayout().toByteArray(event);
if (bytes.length > 0) {
manager.write(bytes);
if (this.immediateFlush || event.isEndOfBatch()) {
manager.flush();
}
}
} catch (final AppenderLoggingException ex) {
error("Unable to write to stream " + manager.getName() + " for appender " + getName());
throw ex;
} finally {
readLock.unlock();
}
}
}