com.ushahidi.swiftriver.core.dropqueue.DropHandler.java Source code

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Here is the source code for com.ushahidi.swiftriver.core.dropqueue.DropHandler.java

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/**
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/agpl.html>
 * 
 * Copyright (C) Ushahidi Inc. All Rights Reserved.
 */
package com.ushahidi.swiftriver.core.dropqueue;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.Map;
import java.util.UUID;

import org.codehaus.jackson.JsonParseException;
import org.codehaus.jackson.map.JsonMappingException;
import org.codehaus.jackson.map.ObjectMapper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.amqp.AmqpException;
import org.springframework.amqp.core.AmqpTemplate;
import org.springframework.amqp.core.Message;
import org.springframework.amqp.core.MessagePostProcessor;
import org.springframework.amqp.core.Queue;
import org.springframework.amqp.rabbit.core.ChannelAwareMessageListener;
import org.springframework.util.ErrorHandler;

import com.rabbitmq.client.Channel;
import com.ushahidi.swiftriver.core.dropqueue.model.RawDrop;

/**
 * Handler for incoming drops on the Drop Queue
 * 
 * Assigns incoming drops a correlation ID and places them in an in memory up
 * before publishing them for meta-data extraction.
 * 
 */
public class DropHandler implements ChannelAwareMessageListener, ErrorHandler {

    final Logger logger = LoggerFactory.getLogger(DropQueueProcessor.class);

    private ObjectMapper objectMapper;

    private AmqpTemplate amqpTemplate;

    private Map<String, RawDrop> dropsMap;

    private Queue callbackQueue;

    private Map<String, DeliveryFrame> deliveryFramesMap;

    public ObjectMapper getObjectMapper() {
        return objectMapper;
    }

    public void setObjectMapper(ObjectMapper objectMapper) {
        this.objectMapper = objectMapper;
    }

    public AmqpTemplate getAmqpTemplate() {
        return amqpTemplate;
    }

    public void setAmqpTemplate(AmqpTemplate amqpTemplate) {
        this.amqpTemplate = amqpTemplate;
    }

    public Map<String, RawDrop> getDropsMap() {
        return dropsMap;
    }

    public void setDropsMap(Map<String, RawDrop> dropsMap) {
        this.dropsMap = dropsMap;
    }

    public Queue getCallbackQueue() {
        return callbackQueue;
    }

    public void setCallbackQueue(Queue callbackQueue) {
        this.callbackQueue = callbackQueue;
    }

    public void setDeliveryFramesMap(Map<String, DeliveryFrame> deliveryFramesMap) {
        this.deliveryFramesMap = deliveryFramesMap;
    }

    /**
     * Receive drops placed on the DROPLET_QUEUE by channel apps.
     * 
     * Caches the drop in the dropsMap for metadata updates and then publishes
     * the drop to the metadata exchange for metadata extraction to be
     * performed.
     * 
     * @param message
     * @throws IOException
     * @throws JsonMappingException
     * @throws JsonParseException
     */
    public synchronized void onMessage(Message message, Channel channel)
            throws JsonParseException, JsonMappingException, IOException {

        RawDrop drop = objectMapper.readValue(new String(message.getBody()), RawDrop.class);

        final String correlationId = UUID.randomUUID().toString();
        final String replyTo = callbackQueue.getName();
        long deliveryTag = message.getMessageProperties().getDeliveryTag();

        dropsMap.put(correlationId, drop);
        DeliveryFrame deliveryFrame = new DeliveryFrame(deliveryTag, channel);
        deliveryFramesMap.put(correlationId, deliveryFrame);

        logger.debug("Sending drop with correlation ID {} to {}", correlationId, replyTo);
        amqpTemplate.convertAndSend(drop, new MessagePostProcessor() {
            public Message postProcessMessage(Message message) throws AmqpException {
                message.getMessageProperties().setReplyTo(replyTo);
                try {
                    message.getMessageProperties().setCorrelationId(correlationId.getBytes("UTF-8"));
                } catch (UnsupportedEncodingException e) {
                    throw new AmqpException(e);
                }
                return message;
            }
        });

        logger.debug("Drop sent for metadata extraction with correlation id '{}'", correlationId);
    }

    public void handleError(Throwable t) {
        logger.error("Error processing drop", t);
    }

}