How to use CaseVariables?

I want to use CaseExecutionListener variable in java class and get vairaibles which were created in embedded html form, after that i want to use these variables in my cmmn RuleTask, here is my java code:
public class IdPersonalizationRuleTask implements CaseExecutionListener{
> String RequestNumber;

	Integer dateInterval;
	public void notify(DelegateCaseExecution caseExecution) throws Exception {
		RequestNumber=(String) caseExecution.getVariable("RequestNumber");
		dateInterval=(Integer) caseExecution.getVariable("dateInterval");
	public void evaluateDecisionTable(ProcessEngine processEngine) {
		DecisionService decisionService = processEngine.getDecisionService();
		VariableMap variables = Variables.createVariables().putValue(""
				+ "RequestNumber",RequestNumber).putValue("dateInterval",

		DmnDecisionTableResult dishDecisionResult = decisionService.evaluateDecisionTableByKey("Priority",
		String priority = dishDecisionResult.getSingleEntry();

but when i run my project , i can see that these values , i mean RequestNumber and dateIntervals are nulls,what should i change to get this form elements values ( RequestNumber and dateIntervals) ?