/*
 * 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.log4j;

import org.apache.log4j.helpers.AppenderAttachableImpl;
import org.apache.log4j.spi.LoggingEvent;

/**
 * Obsolete AsyncAppender dispatcher provided for compatibility only.
 *
 * @deprecated Since 1.3.
 */
class Dispatcher extends Thread {
    /**
     * @deprecated
     */
    private org.apache.log4j.helpers.BoundedFIFO bf;
    private AppenderAttachableImpl aai;
    private boolean interrupted = false;
    AsyncAppender container;

    /**
     * @param bf
     * @param container
     * @deprecated
     */
    Dispatcher(org.apache.log4j.helpers.BoundedFIFO bf, AsyncAppender container) {
        this.bf = bf;
        this.container = container;
        this.aai = container.aai;

        // It is the user's responsibility to close appenders before
        // exiting.
        this.setDaemon(true);

        // set the dispatcher priority to lowest possible value
        this.setPriority(Thread.MIN_PRIORITY);
        this.setName("Dispatcher-" + getName());

        // set the dispatcher priority to MIN_PRIORITY plus or minus 2
        // depending on the direction of MIN to MAX_PRIORITY.
        // + (Thread.MAX_PRIORITY > Thread.MIN_PRIORITY ? 1 : -1)*2);
    }

    void close() {
        synchronized (bf) {
            interrupted = true;

            // We have a waiting dispacther if and only if bf.length is
            // zero. In that case, we need to give it a death kiss.
            if (bf.length() == 0) {
                bf.notify();
            }
        }
    }

    /**
     * The dispatching strategy is to wait until there are events in the buffer to process. After having processed an
     * event, we release the monitor (variable bf) so that new events can be placed in the buffer, instead of keeping
     * the monitor and processing the remaining events in the buffer.
     *
     * <p>
     * Other approaches might yield better results.
     * </p>
     */
    public void run() {
        // Category cat = Category.getInstance(Dispatcher.class.getName());
        LoggingEvent event;

        while (true) {
            synchronized (bf) {
                if (bf.length() == 0) {
                    // Exit loop if interrupted but only if the the buffer is empty.
                    if (interrupted) {
                        // cat.info("Exiting.");
                        break;
                    }

                    try {
                        // LogLog.debug("Waiting for new event to dispatch.");
                        bf.wait();
                    } catch (InterruptedException e) {
                        break;
                    }
                }

                event = bf.get();

                if (bf.wasFull()) {
                    // LogLog.debug("Notifying AsyncAppender about freed space.");
                    bf.notify();
                }
            }

            // synchronized
            synchronized (container.aai) {
                if ((aai != null) && (event != null)) {
                    aai.appendLoopOnAppenders(event);
                }
            }
        }

        // while
        // close and remove all appenders
        aai.removeAllAppenders();
    }
}
