/**
* Copyright 2013 BlackLocus
*
* 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 com.blacklocus.qs.aws.sqs;
import com.amazonaws.services.sqs.AmazonSQS;
import com.amazonaws.services.sqs.model.ChangeMessageVisibilityRequest;
import com.amazonaws.services.sqs.model.DeleteMessageRequest;
import com.amazonaws.services.sqs.model.ReceiveMessageRequest;
import com.blacklocus.qs.Message;
import com.blacklocus.qs.MessageProvider;
import com.google.common.base.Function;
import com.google.common.collect.Lists;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
/**
* Provide Message instances from an SQS queue.
*/
public class AmazonSQSMessageProvider implements MessageProvider {
private static final Logger LOG = LoggerFactory.getLogger(AmazonSQSMessageProvider.class);
private AmazonSQS sqs;
private String queueUrl;
/**
* Create a new MessageProvider instance.
*
* @param sqs AmazonSQS instance to use for communicating with AWS
* @param queueUrl target queue to pull Message instances from
*/
public AmazonSQSMessageProvider(AmazonSQS sqs, String queueUrl) {
this.sqs = sqs;
this.queueUrl = queueUrl;
}
/**
* Returns the queue url for this provider.
*
* @return the queue url for this provider
*/
public String getQueueUrl() {
return queueUrl;
}
@Override
public List<Message> next() {
try {
// receive messages from SQS
ReceiveMessageRequest receiveMessageRequest = new ReceiveMessageRequest(queueUrl)
.withAttributeNames("SentTimestamp", "ApproximateReceiveCount")
.withMaxNumberOfMessages(10);
List<com.amazonaws.services.sqs.model.Message> sqsMessages = sqs.receiveMessage(receiveMessageRequest).getMessages();
return Lists.transform(sqsMessages, new Function<com.amazonaws.services.sqs.model.Message, Message>() {
@Override
public Message apply(com.amazonaws.services.sqs.model.Message input) {
return input != null ? new AmazonSQSMessage(input) : null;
}
});
} catch (Throwable t) {
LOG.error("An error occurred while receiving an SQS message: {}", t);
// sleep to avoid busy wait loop on a receive error
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
LOG.warn("Thread interrupted while sleeping: {}", e);
Thread.currentThread().interrupt();
}
return Collections.emptyList();
}
}
@Override
public void remove() {
throw new UnsupportedOperationException("remove() not supported");
}
@Override
public boolean hasNext() {
return true;
}
@Override
public Iterator<Collection<Message>> iterator() {
return this;
}
@Override
public void delete(Message message) {
sqs.deleteMessage(new DeleteMessageRequest(queueUrl, message.getReceipt()));
}
@Override
public void setVisibilityTimeout(Message message, Integer visibilityTimeoutSeconds) {
sqs.changeMessageVisibility(new ChangeMessageVisibilityRequest(queueUrl, message.getReceipt(), visibilityTimeoutSeconds));
}
}