NotificationMessagingTemplate.java

/*
 * Copyright 2013-2014 the original author or authors.
 *
 * Licensed 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.springframework.cloud.aws.messaging.core;

import com.amazonaws.services.sns.AmazonSNS;
import org.springframework.cloud.aws.core.env.ResourceIdResolver;
import org.springframework.cloud.aws.messaging.core.support.AbstractMessageChannelMessagingSendingTemplate;
import org.springframework.cloud.aws.messaging.support.destination.DynamicTopicDestinationResolver;
import org.springframework.messaging.converter.CompositeMessageConverter;
import org.springframework.messaging.converter.MappingJackson2MessageConverter;
import org.springframework.messaging.converter.MessageConverter;
import org.springframework.messaging.converter.StringMessageConverter;
import org.springframework.messaging.core.DestinationResolver;
import org.springframework.util.ClassUtils;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

/**
 * @author Alain Sahli
 * @since 1.0
 */
public class NotificationMessagingTemplate extends AbstractMessageChannelMessagingSendingTemplate<TopicMessageChannel> {

    private final AmazonSNS amazonSns;

    private static final boolean JACKSON_2_PRESENT = ClassUtils.isPresent(
            "com.fasterxml.jackson.databind.ObjectMapper", NotificationMessagingTemplate.class.getClassLoader());

    public NotificationMessagingTemplate(AmazonSNS amazonSns) {
        this(amazonSns, (ResourceIdResolver) null, null);
    }

    public NotificationMessagingTemplate(AmazonSNS amazonSns, ResourceIdResolver resourceIdResolver) {
        this(amazonSns, resourceIdResolver, null);
    }

    public NotificationMessagingTemplate(AmazonSNS amazonSns, ResourceIdResolver resourceIdResolver, MessageConverter messageConverter) {
        super(new DynamicTopicDestinationResolver(amazonSns, resourceIdResolver));
        this.amazonSns = amazonSns;
        initMessageConverter(messageConverter);
    }

    public NotificationMessagingTemplate(AmazonSNS amazonSns, DestinationResolver<String> destinationResolver, MessageConverter messageConverter) {
        super(destinationResolver);
        this.amazonSns = amazonSns;
        initMessageConverter(messageConverter);
    }

    private void initMessageConverter(MessageConverter messageConverter) {

        StringMessageConverter stringMessageConverter = new StringMessageConverter();
        stringMessageConverter.setSerializedPayloadClass(String.class);

        List<MessageConverter> messageConverters = new ArrayList<>();
        messageConverters.add(stringMessageConverter);

        if (messageConverter != null) {
            messageConverters.add(messageConverter);
        } else if (JACKSON_2_PRESENT) {
            MappingJackson2MessageConverter mappingJackson2MessageConverter = new MappingJackson2MessageConverter();
            mappingJackson2MessageConverter.setSerializedPayloadClass(String.class);
            messageConverters.add(mappingJackson2MessageConverter);
        }

        setMessageConverter(new CompositeMessageConverter(messageConverters));
    }

    @Override
    protected TopicMessageChannel resolveMessageChannel(String physicalResourceIdentifier) {
        return new TopicMessageChannel(this.amazonSns, physicalResourceIdentifier);
    }

    /**
     * Convenience method that sends a notification with the given {@literal message} and {@literal subject} to the {@literal destination}.
     * The {@literal subject} is sent as header as defined in the <a href="http://docs.aws.amazon.com/sns/latest/dg/json-formats.html">SNS message JSON formats</a>.
     *
     * @param destinationName
     *         The logical name of the destination
     * @param message
     *         The message to send
     * @param subject
     *         The subject to send
     */
    public void sendNotification(String destinationName, Object message, String subject) {
        this.convertAndSend(destinationName, message, Collections.<String, Object>singletonMap(TopicMessageChannel.NOTIFICATION_SUBJECT_HEADER, subject));
    }

    /**
     * Convenience method that sends a notification with the given {@literal message} and {@literal subject} to the {@literal destination}.
     * The {@literal subject} is sent as header as defined in the <a href="http://docs.aws.amazon.com/sns/latest/dg/json-formats.html">SNS message JSON formats</a>.
     * The configured default destination will be used.
     *
     * @param message
     *         The message to send
     * @param subject
     *         The subject to send
     */
    public void sendNotification(Object message, String subject) {
        this.convertAndSend(getRequiredDefaultDestination(), message, Collections.<String, Object>singletonMap(TopicMessageChannel.NOTIFICATION_SUBJECT_HEADER, subject));
    }
}