activemq-core/src/main/java/org/apache/activemq/transport/stomp/FrameTranslator.java

/**
 *
 * 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.activemq.transport.stomp;

import org.apache.activemq.command.ActiveMQMessage;
import org.apache.activemq.command.ActiveMQDestination;

import javax.jms.JMSException;
import javax.jms.Destination;
import java.io.IOException;
import java.util.Map;
import java.util.HashMap;

/**
 * Implementations of this interface are used to map back and forth from Stomp to ActiveMQ.
 * There are several standard mappings which are semantically the same, the inner class,
 * Helper, provides functions to copy those properties from one to the other
 */
public interface FrameTranslator
{
    public ActiveMQMessage convertFrame(StompFrame frame) throws JMSException, ProtocolException;

    public StompFrame convertMessage(ActiveMQMessage message) throws IOException, JMSException;

    public String convertDestination(Destination d);

    public ActiveMQDestination convertDestination(String name) throws ProtocolException;

    /**
     * Helper class which holds commonly needed functions used when implementing
     * FrameTranslators
     */
    public final static class Helper
    {
        public static void copyStandardHeadersFromMessageToFrame(ActiveMQMessage message,
                                                                 StompFrame command,
                                                                 FrameTranslator ft)
                throws IOException
        {
            final Map headers = command.getHeaders();
            headers.put(Stomp.Headers.Message.DESTINATION, ft.convertDestination(message.getDestination()));
            headers.put(Stomp.Headers.Message.MESSAGE_ID, message.getJMSMessageID());

            if (message.getJMSCorrelationID() != null) {
                headers.put(Stomp.Headers.Message.CORRELATION_ID, message.getJMSCorrelationID());
            }
            headers.put(Stomp.Headers.Message.EXPIRATION_TIME, ""+message.getJMSExpiration());

            if (message.getJMSRedelivered()) {
                headers.put(Stomp.Headers.Message.REDELIVERED, "true");
            }
            headers.put(Stomp.Headers.Message.PRORITY, ""+message.getJMSPriority());

            if (message.getJMSReplyTo() != null) {
                headers.put(Stomp.Headers.Message.REPLY_TO, ft.convertDestination(message.getJMSReplyTo()));
            }
            headers.put(Stomp.Headers.Message.TIMESTAMP, ""+message.getJMSTimestamp());

            if (message.getJMSType() != null) {
                headers.put(Stomp.Headers.Message.TYPE, message.getJMSType());
            }

            // now lets add all the message headers
            final Map properties = message.getProperties();
            if (properties != null) {
                headers.putAll(properties);
            }
        }

        public static void copyStandardHeadersFromFrameToMessage(StompFrame command,
                                                                 ActiveMQMessage msg,
                                                                 FrameTranslator ft)
                throws ProtocolException, JMSException
        {
            final Map headers = new HashMap(command.getHeaders());
            final String destination = (String) headers.remove(Stomp.Headers.Send.DESTINATION);
            msg.setDestination( ft.convertDestination(destination));

            // the standard JMS headers
            msg.setJMSCorrelationID((String) headers.remove(Stomp.Headers.Send.CORRELATION_ID));

            Object o = headers.remove(Stomp.Headers.Send.EXPIRATION_TIME);
            if (o != null) {
                msg.setJMSExpiration(Long.parseLong((String) o));
            }

            o = headers.remove(Stomp.Headers.Send.PRIORITY);
            if (o != null) {
                msg.setJMSPriority(Integer.parseInt((String) o));
            }

            o = headers.remove(Stomp.Headers.Send.TYPE);
            if (o != null) {
                msg.setJMSType((String) o);
            }

            o = headers.remove(Stomp.Headers.Send.REPLY_TO);
            if (o != null) {
                msg.setJMSReplyTo(ft.convertDestination((String) o));
            }

            o = headers.remove(Stomp.Headers.Send.PERSISTENT);
            if (o != null) {
                msg.setPersistent("true".equals(o));
            }

            // now the general headers
            msg.setProperties(headers);
        }
    }
}