vaniglia 源码学习（五）

vaniglia message quene特性主要实现一个消息队列，功能如下：

public class Main {



    private static final Logger logger = Logger.getLogger(Main.class);



    public static void main(String[] args) throws MessageQueueException {

        MessageQueue queue = MessageQueue.getQueue("MyQueue", MessageStorageType.MemoryType,

                MessageStorageParameters.createMemoryStorageParameters("MyStorage", 1000));



        queue.start();



        queue.subscribe(new MyQueueListener());



        MyQueuePublisher myQueuePublisher = new MyQueuePublisher(queue);

        Thread publishingThread = new Thread(myQueuePublisher);

        publishingThread.setDaemon(true);

        logger.info("Starting the publisher.");

        publishingThread.start();



        queue.stop();

    }

}

MessageQueue 通过getQueue产生一个消息队列，参数MessageStorageType设定消息的存储类型（内存、文件、数据库等），MessageStorageParameters存储存储类型的参数。

其中MyQueueListner为消息监听器（用户继承接口实现），有消息在队列中时触发处理。myQueuePublisher是消息写入线程，通过调用MessageQueue的push接口向队列中填入消息。主要的类图有两部分：

一部分是MessageStorageType:

 

二.消息队列的业务

在MesssageQueue中启动Timer线程，调用MessageQueueProcessingTask，如下：

 

    public void start(long interval) throws MessageQueueException {

        if (timerThread == null) {

            logger.info("Starting queue "+name+" with processing interval = "+interval+"ms");

            timerThread = new Timer(true);

            processingTask = new MessageQueueProcessingTask(this);

            timerThread.scheduleAtFixedRate(processingTask, interval, interval);

        }

        else {

            throw new MessageQueueException("Queue "+name+" already running.");

        }

    }

 

 

 

比较值得学习的代码有：

public abstract class MessageStorageParameters {



    public static class MemoryStorageParameters extends MessageStorageParameters {

        private long size;

        public MemoryStorageParameters(String name, long size) {

            super(name);

            this.size = size;

        }

        public long getSize() {

            return size;

        }

    }

    public static class FileSystemStorageParameters extends MessageStorageParameters {

        private String basedir;



        public FileSystemStorageParameters(String name) {

            super(name);

        }

        public FileSystemStorageParameters(String name, String basedir) {

            super(name);

            this.basedir = basedir;

        }

        public String getBasedir() {

            return basedir;

        }

    }

    public static class JDBCStorageParameters extends MessageStorageParameters {

        public JDBCStorageParameters(String name) {

            super(name);

        }

    }

    /**

     * Creates a Memory Storage Parameters given its name and size limit.

     *

     * @param name the storage name

     * @param size the storage size limit or -1 to avoid size limit checking.

     *

     * @return the newly created MemoryStorageParameters object

     */

    public static MessageStorageParameters createMemoryStorageParameters(String name, long size) {

        return new MemoryStorageParameters(name, size);

    }

    /**

     * Creates a FileSystem Storage Paramters given its name and basedir.

     *

     * @param name the storage name

     * @param basedir the storage basedir

     *

     * @return the newly create FileSystemStorageParamters object

     */

    public static MessageStorageParameters createFileSystemStorageParameters(String name, String basedir) {

        return new FileSystemStorageParameters(name, basedir);

    }



    /**

     * Creates a FileSystem Storage Paramters given its name.

     *

     * @param name the storage name

     *

     * @return the newly create FileSystemStorageParamters object

     */

    public static MessageStorageParameters createFileSystemStorageParameters(String name) {

        return new FileSystemStorageParameters(name);

    }

    public static MessageStorageParameters createJDBCStorageParameters(String name) {

        return new JDBCStorageParameters(name);

    }

    protected String name;

    protected MessageStorageParameters(String name) {

        this.name = name;

    }

    public String getName() {

        return name;

    }

    public void setName(String name) {

        this.name = name;

    }

}