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ActiveMQ example source code file (Subscription.java)

This example ActiveMQ source code file (Subscription.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - ActiveMQ tags/keywords

destination, destination, exception, exception, invalidselectorexception, io, ioexception, ioexception, management, messageack, messageack, messageevaluationcontext, objectname, response, subscription, subscriptionrecovery, util

The ActiveMQ Subscription.java source code

/**
 * 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.broker.region;

import java.io.IOException;
import java.util.List;

import javax.jms.InvalidSelectorException;
import javax.management.ObjectName;

import org.apache.activemq.broker.ConnectionContext;
import org.apache.activemq.command.ActiveMQDestination;
import org.apache.activemq.command.ConsumerInfo;
import org.apache.activemq.command.MessageAck;
import org.apache.activemq.command.MessageDispatchNotification;
import org.apache.activemq.command.MessagePull;
import org.apache.activemq.command.Response;
import org.apache.activemq.filter.MessageEvaluationContext;

/**
 * 
 */
public interface Subscription extends SubscriptionRecovery {

    /**
     * Used to add messages that match the subscription.
     * @param node
     * @throws Exception 
     * @throws InterruptedException 
     * @throws IOException 
     */
    void add(MessageReference node) throws Exception;
    
    /**
     * Used when client acknowledge receipt of dispatched message. 
     * @param node
     * @throws IOException 
     * @throws Exception 
     */
    void acknowledge(ConnectionContext context, final MessageAck ack) throws Exception;
    

    /**
     * Allows a consumer to pull a message on demand
     */
    Response pullMessage(ConnectionContext context, MessagePull pull) throws Exception;

    /**
     * Is the subscription interested in the message?
     * @param node 
     * @param context
     * @return
     * @throws IOException 
     */
    boolean matches(MessageReference node, MessageEvaluationContext context) throws IOException;
    
    /**
     * Is the subscription interested in messages in the destination?
     * @param context
     * @return
     */
    boolean matches(ActiveMQDestination destination);
    
    /**
     * The subscription will be receiving messages from the destination.
     * @param context 
     * @param destination
     * @throws Exception 
     */
    void add(ConnectionContext context, Destination destination) throws Exception;
    
    /**
     * The subscription will be no longer be receiving messages from the destination.
     * @param context 
     * @param destination
     * @return a list of un-acked messages that were added to the subscription.
     */
    List<MessageReference> remove(ConnectionContext context, Destination destination) throws Exception;
    
    /**
     * The ConsumerInfo object that created the subscription.
     * @param destination
     */
    ConsumerInfo getConsumerInfo();

    /**
     * The subscription should release as may references as it can to help the garbage collector
     * reclaim memory.
     */
    void gc();
    
    /**
     * Used by a Slave Broker to update dispatch infomation
     * @param mdn
     * @throws Exception 
     */
    void processMessageDispatchNotification(MessageDispatchNotification  mdn) throws Exception;
    
    /**
     * @return true if the broker is currently in slave mode
     */
    boolean isSlave();
    
    /**
     * @return number of messages pending delivery
     */
    int getPendingQueueSize();
    
    /**
     * @return number of messages dispatched to the client
     */
    int getDispatchedQueueSize();
        
    /**
     * @return number of messages dispatched to the client
     */
    long getDispatchedCounter();
    
    /**
     * @return number of messages that matched the subscription
     */
    long getEnqueueCounter();

    /**
     * @return number of messages queued by the client
     */
    long getDequeueCounter();

    /**
     * @return the JMS selector on the current subscription
     */
    String getSelector();
    
    /**
     * Attempts to change the current active selector on the subscription.
     * This operation is not supported for persistent topics.
     */
    void setSelector(String selector) throws InvalidSelectorException, UnsupportedOperationException;

    /**
     * @return the JMX object name that this subscription was registered as if applicable
     */
    ObjectName getObjectName();

    /**
     * Set when the subscription is registered in JMX
     */
    void setObjectName(ObjectName objectName);
    
    /**
     * @return true when 60% or more room is left for dispatching messages
     */
    boolean isLowWaterMark();
    
    /**
     * @return true when 10% or less room is left for dispatching messages
     */
    boolean isHighWaterMark();
    
    /**
     * @return true if there is no space to dispatch messages
     */
    boolean isFull();
    
    /**
     * inform the MessageConsumer on the client to change it's prefetch
     * @param newPrefetch
     */
    void updateConsumerPrefetch(int newPrefetch);
    
        
    /**
     * Called when the subscription is destroyed.
     */
    void destroy();

    /**
     * @return the prefetch size that is configured for the subscription
     */
    int getPrefetchSize();
    
    /**
     * @return the number of messages awaiting acknowledgement
     */
    int getInFlightSize();
    
    /**
     * @return the in flight messages as a percentage of the prefetch size
     */
    int getInFlightUsage();
    
    /**
     * Informs the Broker if the subscription needs to intervention to recover it's state
     * e.g. DurableTopicSubscriber may do
     * @see org.apache.activemq.region.cursors.PendingMessageCursor
     * @return true if recovery required
     */
    boolean isRecoveryRequired();
    
    
    /**
     * @return true if a browser
     */
    boolean isBrowser();
    
    /**
     * @return the number of messages this subscription can accept before its full
     */
    int countBeforeFull();

    ConnectionContext getContext();
    
    public int getCursorMemoryHighWaterMark();

	public void setCursorMemoryHighWaterMark(int cursorMemoryHighWaterMark);

    boolean isSlowConsumer();

    void unmatched(MessageReference node) throws IOException;
}

Other ActiveMQ examples (source code examples)

Here is a short list of links related to this ActiveMQ Subscription.java source code file:

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