scheduler.SQSService.java Source code

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Here is the source code for scheduler.SQSService.java

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/*
 * 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 scheduler;

import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;

import com.amazonaws.AmazonClientException;
import com.amazonaws.AmazonServiceException;
import com.amazonaws.auth.AWSCredentials;
import com.amazonaws.auth.profile.ProfileCredentialsProvider;
import com.amazonaws.regions.Region;
import com.amazonaws.regions.Regions;
import com.amazonaws.services.sqs.AmazonSQS;
import com.amazonaws.services.sqs.AmazonSQSClient;
import com.amazonaws.services.sqs.model.CreateQueueRequest;
import com.amazonaws.services.sqs.model.GetQueueAttributesRequest;
import com.amazonaws.services.sqs.model.Message;
import com.amazonaws.services.sqs.model.ReceiveMessageRequest;
import com.amazonaws.services.sqs.model.SendMessageBatchRequest;
import com.amazonaws.services.sqs.model.SendMessageBatchRequestEntry;
import com.amazonaws.services.sqs.model.SendMessageBatchResult;
import com.amazonaws.services.sqs.model.DeleteMessageRequest;

public class SQSService {
    private AmazonSQS sqs;
    private String queueUrl;

    public SQSService(String queueName) {
        /*
           * The ProfileCredentialsProvider will return your [default]
           * credential profile by reading from the credentials file located at
           * (~/.aws/credentials).
           */
        AWSCredentials credentials = null;
        try {
            credentials = new ProfileCredentialsProvider().getCredentials();
        } catch (Exception e) {
            throw new AmazonClientException("Cannot load the credentials from the credential profiles file. "
                    + "Please make sure that your credentials file is at the correct "
                    + "location (~/.aws/credentials), and is in valid format.", e);
        }

        sqs = new AmazonSQSClient(credentials);
        Region usEast1 = Region.getRegion(Regions.US_EAST_1);
        sqs.setRegion(usEast1);

        // Create a queue or returns the URL of an existing one
        //System.out.println("Creating a new SQS queue called " + queueName);
        CreateQueueRequest createQueueRequest = new CreateQueueRequest(queueName);
        queueUrl = sqs.createQueue(createQueueRequest).getQueueUrl();

    }

    public void batchSend(List<SendMessageBatchRequestEntry> entries) {

        try {
            // Send batch messages
            //System.out.println("\nSending a message to jobQueue.\n");

            SendMessageBatchRequest batchRequest = new SendMessageBatchRequest().withQueueUrl(queueUrl);
            batchRequest.setEntries(entries);

            SendMessageBatchResult batchResult = sqs.sendMessageBatch(batchRequest);

            // sendMessageBatch can return successfully, and yet individual batch
            // items fail. So, make sure to retry the failed ones.
            if (!batchResult.getFailed().isEmpty()) {
                //System.out.println("Retry sending failed messages...");

                List<SendMessageBatchRequestEntry> failedEntries = new ArrayList<SendMessageBatchRequestEntry>();
                Iterator<SendMessageBatchRequestEntry> iter = entries.iterator();

                while (iter.hasNext()) {
                    if (batchResult.getFailed().contains(iter.next())) {
                        failedEntries.add((SendMessageBatchRequestEntry) iter.next());
                    }
                }

                batchRequest.setEntries(failedEntries);
                sqs.sendMessageBatch(batchRequest);
            }

        } catch (AmazonServiceException ase) {
            System.out.println("Caught an AmazonServiceException, which means your request made it "
                    + "to Amazon SQS, but was rejected with an error response for some reason.");
            System.out.println("Error Message:    " + ase.getMessage());
            System.out.println("HTTP Status Code: " + ase.getStatusCode());
            System.out.println("AWS Error Code:   " + ase.getErrorCode());
            System.out.println("Error Type:       " + ase.getErrorType());
            System.out.println("Request ID:       " + ase.getRequestId());
        } catch (AmazonClientException ace) {
            System.out.println("Caught an AmazonClientException, which means the client encountered "
                    + "a serious internal problem while trying to communicate with SQS, such as not "
                    + "being able to access the network.");
            System.out.println("Error Message: " + ace.getMessage());
        }

    }

    public List<Message> batchReceive() {
        //Batch retrieving messages
        ReceiveMessageRequest receiveMessageRequest = new ReceiveMessageRequest().withQueueUrl(queueUrl)
                .withMaxNumberOfMessages(10);

        List<Message> messages = sqs.receiveMessage(receiveMessageRequest).getMessages();

        return messages;

    }

    public int getQueueSize() {
        HashMap<String, String> attributes;

        Collection<String> attributeNames = new ArrayList<String>();
        attributeNames.add("ApproximateNumberOfMessages");

        GetQueueAttributesRequest getAttributesRequest = new GetQueueAttributesRequest(queueUrl)
                .withAttributeNames(attributeNames);
        attributes = (HashMap<String, String>) sqs.getQueueAttributes(getAttributesRequest).getAttributes();

        return Integer.valueOf(attributes.get("ApproximateNumberOfMessages"));

    }

    public void deleteMessage(String messageRecieptHandle) {
        sqs.deleteMessage(new DeleteMessageRequest(queueUrl, messageRecieptHandle));

    }

}