com.dell.cpsd.common.rabbitmq.consumer.handler.GenericMessageHandler Maven / Gradle / Ivy

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/**
 * Copyright © 2017 Dell Inc. or its subsidiaries.  All Rights Reserved.
 * Dell EMC Confidential/Proprietary Information
 */

package com.dell.cpsd.common.rabbitmq.consumer.handler;

import com.dell.cpsd.common.logging.ILogger;
import com.dell.cpsd.common.rabbitmq.consumer.LoggingUnhandledMessageHandler;
import com.dell.cpsd.common.rabbitmq.context.RabbitContext;
import com.dell.cpsd.common.rabbitmq.context.RabbitContextAware;
import com.dell.cpsd.common.rabbitmq.log.RabbitMQLoggingManager;

import java.util.UUID;

/**
 * This is a generic handler base class.
 * 
 * Copyright © 2017 Dell Inc. or its subsidiaries.  All Rights Reserved.
 * Dell EMC Confidential/Proprietary Information
 * 
 *
 * @since SINCE-TBD
 */
public abstract class GenericMessageHandler extends LoggingUnhandledMessageHandler
        implements RabbitContextAware
{
    /*
     * The logger for this class.
     */
    private static final ILogger LOGGER = RabbitMQLoggingManager.getLogger(GenericMessageHandler.class);

    protected RabbitContext rabbitContext;

    /**
     * GenericMessageHandler constructor.
     *
     * @since 1.0
     */
    public GenericMessageHandler()
    {
        this("GenericMessageHandler@" + UUID.randomUUID().toString());
    }

    /**
     * GenericMessageHandler constructor.
     *
     * @param consumerName The consumer identifier.
     * @since 1.0
     */
    public GenericMessageHandler(String consumerName)
    {
        super(consumerName);
    }

    /**
     * This executes the operation This might include updating a database,
     * sending further messages to continue the conversation.
     *
     * @param requestMessage The message to process.
     * @throws Throwable Thrown if there operation fails.
     * @since 1.0
     */
    protected abstract void executeOperation(final R requestMessage) throws Throwable;

    /**
     * This handles the message.
     *
     * @param requestMessage The message to handle.
     * @since 1.0
     */
    public void handleMessage(final R requestMessage) throws E
    {
        try
        {
            executeOperation(requestMessage);
        }
        catch (Throwable e)
        {
            LOGGER.error(e.getMessage(), e);
        }
        finally
        {
            cleanup(requestMessage);
        }
    }

    /**
     * This performs an required cleanup after the message is handled.
     *
     * @param requestMessage The request message.
     * @since 1.0
     */
    protected void cleanup(final R requestMessage)
    {
        // do nothing by default
    }

    /**
     * This converts an exception.
     *
     * @param t The Throwable to convert.
     * @return The converted exception.
     * @since 1.0
     */
    protected abstract E convertException(Throwable t);

    @Override
    public void setRabbitContext(RabbitContext rabbitContext)
    {
        this.rabbitContext = rabbitContext;
    }
}