/*
 * 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.util.concurrent.TimeUnit;
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.LogEvent;
import org.apache.logging.log4j.core.StringLayout;
import org.apache.logging.log4j.core.config.Property;

Appends log events as strings to a writer.
Type parameters:
<M> –  The kind of WriterManager under management/**
 * Appends log events as strings to a writer.
 *
 * @param <M>
 *            The kind of {@link WriterManager} under management
 */
public abstract class AbstractWriterAppender<M extends WriterManager> extends AbstractAppender {

    
Immediate flush means that the underlying writer 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 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. /**
     * Immediate flush means that the underlying writer will be flushed at the
     * end of each append operation. Immediate flush is slower but ensures that
     * each append request is actually written. If <code>immediateFlush</code>
     * 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 readWriteLock = new ReentrantReadWriteLock();
    private final Lock readLock = readWriteLock.readLock();

    
Instantiates.
Params:
name – 
           The name of the Appender.
layout – 
           The layout to format the message.
properties – 
           Optional properties.
manager – 
           The OutputStreamManager./**
     * Instantiates.
     *
     * @param name
     *            The name of the Appender.
     * @param layout
     *            The layout to format the message.
     * @param properties
     *            Optional properties.
     * @param manager
     *            The OutputStreamManager.
     */
    protected AbstractWriterAppender(final String name, final StringLayout layout, final Filter filter,
            final boolean ignoreExceptions, final boolean immediateFlush, final Property[] properties, final M manager) {
        super(name, filter, layout, ignoreExceptions, properties);
        this.manager = manager;
        this.immediateFlush = immediateFlush;
    }

    
Instantiates.
Params:
name – 
           The name of the Appender.
layout – 
           The layout to format the message.
manager – 
           The OutputStreamManager.
Deprecated:
Use AbstractWriterAppender(String, StringLayout, Filter, boolean, boolean, Property[], WriterManager)./**
     * Instantiates.
     *
     * @param name
     *            The name of the Appender.
     * @param layout
     *            The layout to format the message.
     * @param manager
     *            The OutputStreamManager.
     * @deprecated Use {@link #AbstractWriterAppender(String, StringLayout, Filter, boolean, boolean, Property[], WriterManager)}.
     */
    @Deprecated
    protected AbstractWriterAppender(final String name, final StringLayout layout, final Filter filter,
            final boolean ignoreExceptions, final boolean immediateFlush, final M manager) {
        super(name, filter, layout, ignoreExceptions, Property.EMPTY_ARRAY);
        this.manager = manager;
        this.immediateFlush = immediateFlush;
    }

    
Actual writing occurs here.

Most subclasses will need to override this method.

Params:
event – 
           The LogEvent./**
     * Actual writing occurs here.
     * <p>
     * Most subclasses will need to override this method.
     * </p>
     *
     * @param event
     *            The LogEvent.
     */
    @Override
    public void append(final LogEvent event) {
        readLock.lock();
        try {
            final String str = getStringLayout().toSerializable(event);
            if (str.length() > 0) {
                manager.write(str);
                if (this.immediateFlush || event.isEndOfBatch()) {
                    manager.flush();
                }
            }
        } catch (final AppenderLoggingException ex) {
            error("Unable to write " + manager.getName() + " for appender " + getName(), event, ex);
            throw ex;
        } finally {
            readLock.unlock();
        }
    }

    
Gets the manager.
Returns:
the manager./**
     * Gets the manager.
     *
     * @return the manager.
     */
    public M getManager() {
        return manager;
    }

    public StringLayout getStringLayout() {
        return (StringLayout) getLayout();
    }

    @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 boolean stop(final long timeout, final TimeUnit timeUnit) {
        setStopping();
        boolean stopped = super.stop(timeout, timeUnit, false);
        stopped &= manager.stop(timeout, timeUnit);
        setStopped();
        return stopped;
    }
}