PIOT-GDA-02-006: Create module - SystemMemUtilTask

[labbenchstudios]

Description

• Create the SystemMemUtilTask module and implement the functionality to retrieve JVM memory utilization.

Review the README

• Please see README.md for further information on, and use of, this content.
• License for embedded documentation and source codes: PIOT-DOC-LIC

Estimated effort may vary greatly

• The estimated level of effort for this exercise shown in the 'Estimate' section below is a very rough approximation. The actual level of effort may vary greatly depending on your development and test environment, experience with the requisite technologies, and many other factors.

Actions

NOTE: The implementation examples depicted here are only one way to implement the requirements listed. Your own implementation may vary of course.

• Within the programmingtheiot.gda.system package, create a new Java class named SystemMemUtilTask. This should be derived from BaseSystemUtilTask.
• Import statements should include the following (you may choose to include the Logger for debugging):

  
  import java.lang.management.ManagementFactory;
  import java.lang.management.MemoryUsage;

import java.util.logging.Logger;

import programmingtheiot.common.ConfigConst;

- Add in an override for the inherited template method `getTelemetryValue()`. It will retrieve JVM memory utilization and return the value as a float. Use the `@Override` annotation and be sure to remove the abstract keyword if you're copying / pasting from the base class. You'll have to perform a simple calculation to derive this, as follows:
```java
MemoryUsage memUsage = ManagementFactory.getMemoryMXBean().getHeapMemoryUsage();
double memUtil = ((double) memUsage.getUsed() / (double) memUsage.getMax()) * 100.0d;

• Log the value, then return it as a float (once the value is calculated, for our purposes, it's OK to cast from double to float)
• Here's one way to implement these requirements (your own implementation may vary from this). Also note that this may not work with all OSes:

  
  public SystemMemUtilTask()
  {
  super(ConfigConst.NOT_SET, ConfigConst.DEFAULT_TYPE_ID);
  }

@Override public float getTelemetryValue() { MemoryUsage memUsage = ManagementFactory.getMemoryMXBean().getHeapMemoryUsage(); double memUsed = (double) memUsage.getUsed(); double memMax = (double) memUsage.getMax();

_Logger.fine("Mem used: " + memUsed + "; Mem Max: " + memMax);

double memUtil = (memUsed / memMax) * 100.0d;

return (float) memUtil;

}

**Estimate**

- Small

**Tests**

- Unit tests (in ./src/test/java/programmingtheiot/part01/unit)
  - Run `./system/SystemMemUtilTaskTest`. The `testGetTelemetryValue()` unit test should pass while logging values between 0.0% and 100.0%.

[htayyar]

in order to use _Logger from BaseSystemUtilTask, it should become protected or public in BaseSystemUtilTask:

protected static final Logger _Logger = Logger.getLogger(BaseSystemUtilTask.class.getName());

[labbenchstudios]

Logging is on a per class / type basis, so each specific type has its own private instance by design.