The AWS SDK for Java 1.x has entered maintenance mode as of July 31, 2024, and will reach end-of-support on December 31, 2025. We recommend that you migrate to the AWS SDK for Java 2.x to continue receiving new features, availability improvements, and security updates.

Working with CloudWatch Alarms

Create an Alarm

To create an alarm based on a CloudWatch metric, call the AmazonCloudWatchClient’s putMetricAlarm method with a PutMetricAlarmRequest filled with the alarm conditions.

Imports

import com.amazonaws.services.cloudwatch.AmazonCloudWatch;
import com.amazonaws.services.cloudwatch.AmazonCloudWatchClientBuilder;
import com.amazonaws.services.cloudwatch.model.ComparisonOperator;
import com.amazonaws.services.cloudwatch.model.Dimension;
import com.amazonaws.services.cloudwatch.model.PutMetricAlarmRequest;
import com.amazonaws.services.cloudwatch.model.PutMetricAlarmResult;
import com.amazonaws.services.cloudwatch.model.StandardUnit;
import com.amazonaws.services.cloudwatch.model.Statistic;

Code

final AmazonCloudWatch cw =
    AmazonCloudWatchClientBuilder.defaultClient();

Dimension dimension = new Dimension()
    .withName("InstanceId")
    .withValue(instanceId);

PutMetricAlarmRequest request = new PutMetricAlarmRequest()
    .withAlarmName(alarmName)
    .withComparisonOperator(
        ComparisonOperator.GreaterThanThreshold)
    .withEvaluationPeriods(1)
    .withMetricName("CPUUtilization")
    .withNamespace("{AWS}/EC2")
    .withPeriod(60)
    .withStatistic(Statistic.Average)
    .withThreshold(70.0)
    .withActionsEnabled(false)
    .withAlarmDescription(
        "Alarm when server CPU utilization exceeds 70%")
    .withUnit(StandardUnit.Seconds)
    .withDimensions(dimension);

PutMetricAlarmResult response = cw.putMetricAlarm(request);

List Alarms

To list the CloudWatch alarms that you have created, call the AmazonCloudWatchClient’s describeAlarms method with a DescribeAlarmsRequest that you can use to set options for the result.

Imports

import com.amazonaws.services.cloudwatch.AmazonCloudWatch;
import com.amazonaws.services.cloudwatch.AmazonCloudWatchClientBuilder;
import com.amazonaws.services.cloudwatch.model.DescribeAlarmsRequest;
import com.amazonaws.services.cloudwatch.model.DescribeAlarmsResult;
import com.amazonaws.services.cloudwatch.model.MetricAlarm;

Code

final AmazonCloudWatch cw =
    AmazonCloudWatchClientBuilder.defaultClient();

boolean done = false;
DescribeAlarmsRequest request = new DescribeAlarmsRequest();

while(!done) {

    DescribeAlarmsResult response = cw.describeAlarms(request);

    for(MetricAlarm alarm : response.getMetricAlarms()) {
        System.out.printf("Retrieved alarm %s", alarm.getAlarmName());
    }

    request.setNextToken(response.getNextToken());

    if(response.getNextToken() == null) {
        done = true;
    }
}

The list of alarms can be obtained by calling getMetricAlarms on the DescribeAlarmsResult that is returned by describeAlarms.

The results may be paged. To retrieve the next batch of results, call setNextToken on the original request object with the return value of the DescribeAlarmsResult object’s getNextToken method, and pass the modified request object back to another call to describeAlarms.

Delete Alarms

To delete CloudWatch alarms, call the AmazonCloudWatchClient’s deleteAlarms method with a DeleteAlarmsRequest containing one or more names of alarms that you want to delete.

Imports

import com.amazonaws.services.cloudwatch.AmazonCloudWatch;
import com.amazonaws.services.cloudwatch.AmazonCloudWatchClientBuilder;
import com.amazonaws.services.cloudwatch.model.DeleteAlarmsRequest;
import com.amazonaws.services.cloudwatch.model.DeleteAlarmsResult;

Code

final AmazonCloudWatch cw =
    AmazonCloudWatchClientBuilder.defaultClient();

DeleteAlarmsRequest request = new DeleteAlarmsRequest()
    .withAlarmNames(alarm_name);

DeleteAlarmsResult response = cw.deleteAlarms(request);

More Information