Derived Measure - aabherve/measure-smm-measure-api GitHub Wiki

Derived Measure API

A Derived measure is used to defined a combined measure which will calculate new measurements using one or more measurements stored on measure platform.

To defined a Direct Measure, implement the IDerivedMeasure interface. This interface will be called by the MeasurePlatform to calculate the measurement.

public interface IDerivedMeasure {
	public List<IMeasurement> calculateMeasurement() throws Exception;
        public void addMeasureInput(String reference,String role, IMeasurement value);
        public Map<String,String> getProperties();
}

calculateMeasurement() : Calculate and Return a liste of Measurement based on provided measurement imputs.
addMeasureInput() : Provide a way for the MeasurePlatform to communicate input measurementto the DerivedMeasure implementation.
getProperties() : Provide a way for the MeasurePlatform to communicate properties to the DerivedMeasure implementation.

To implement a derived measure, please extend the **DerivedMeasure **class.

Properties

For more details about properties:
https://github.com/aabherve/measure-smm-measure-api/wiki/Measure-Properties

Inputs Measurements

Required Measurements are defined on the MetaData.xml. Thes references are identified by a measureRef and a role.

The **measureRef ** is the id the measure which can provide a measurement as imput.
The role is the Role of the imput in current Measurement. This role allow to identifyseveral instance of the same Measure in a DerivedMeasure.
The expirationDelay property allow to filter as input the measures which has been calculated recently
The number property allow to select the number of input of this type which will be communicated to derived measure implementation by the platform.

    <references expirationDelay="60000" measureRef="RandomGenerator" number="1">
        <role>RandomNumber A</role>
    </references>
    <references expirationDelay="60000" measureRef="RandomGenerator" number="1">
        <role>RandomNumber B</role>
    </references>

Inputs are defined when a Instance on the measure is created on MeasurePlatform

Derived Measure Examples

RandomBinaryMeasure : A toy measure whch return the result of a binary operation between two RandomGenerator result .

public class RandomBinaryMeasure extends DerivedMeasure {
	
	@Override
	public List<IMeasurement> calculateMeasurement() {
		Integer result = 0;
		
                // Retrive input Measurements by her Role
		List<IMeasurement> op1 = getMeasureInputByRole("RandomNumber A");
		List<IMeasurement> op2 = getMeasureInputByRole("RandomNumber B");
		
                // Calculate result 
		if(op1.size() == 1 && op2.size() == 1){			
			String oper = "+";	

                        // Retrive the operator as Property
			oper = getProperty("Operation");	
			
			Integer val1 =   (Integer) op1.get(0).getValues().get("value");
			Integer val2 =   (Integer) op2.get(0).getValues().get("value");
		
			if(oper.equals("+")){
				result = val1 + val2;
			}else if(oper.equals("-")){
				result = val1 - val2;
			}else if(oper.equals("*")){
				result = val1 * val2;
			}else if(oper.equals("/")){
				result = val1 / val2;
			}	
		}
		
		// Return result as  new IntegerMeasurement
		IntegerMeasurement measurement = new IntegerMeasurement();
		measurement.setValue(result);
		
		List<IMeasurement> measurements = new ArrayList<>();
		measurements.add(measurement);
		
		return measurements;
	}
}

RandomSumMeasure : A toy measure whch return the sum of measurements provided by the RandomGenerator measure.

public class RandomSumImpl extends DerivedMeasure {
	@Override
	public List<IMeasurement> calculateMeasurement() throws Exception {
		Integer result = 0;
		for (IMeasurement operande : getMeasureInputByRole("RandomNumber")) {
			try {
				result = result + (Integer) operande.getValues().get("value");
			} catch (NumberFormatException e) {
				System.out.println("Non Numeric Operande");
			}
		}

		IntegerMeasurement measurement = new IntegerMeasurement();
		measurement.setValue(result);

		List<IMeasurement> measurements = new ArrayList<>();
		measurements.add(measurement);
		return measurements;
	}
}