package org.kuali.rice.krms.framework.engine;

 import java.util.Collections;

 import java.util.List;

 import org.kuali.rice.krms.api.engine.ExecutionEnvironment;

 import org.kuali.rice.krms.api.engine.ResultEvent;

 import org.kuali.rice.krms.api.engine.Term;

 import org.kuali.rice.krms.api.engine.TermResolutionException;

 import org.kuali.rice.krms.framework.engine.result.BasicResult;

 public class ComparableTermBasedProposition<T> implements Proposition {

         private static final ResultLogger LOG = ResultLogger.getInstance();

         private final ComparisonOperator operator;

         private final Term term;

         private final T expectedValue;

         public ComparableTermBasedProposition(ComparisonOperator operator, Term term, T expectedValue) {

                 this.operator = operator;

                 this.term = term;

                 this.expectedValue = expectedValue;

         }

         /**

          * @see org.kuali.rice.krms.framework.engine.Proposition#evaluate(org.kuali.rice.krms.api.engine.ExecutionEnvironment)

          * @throws TermResolutionException if there is a problem resolving the {@link Term}

          */

         @Override

         public boolean evaluate(ExecutionEnvironment environment) {

                 Comparable<T> termValue;

                 termValue = environment.resolveTerm(term);

                 boolean result = compare(termValue);

                 if (LOG.isEnabled(environment)){

                         LOG.logResult(new BasicResult(ResultEvent.PropositionEvaluated, this, environment, result));

                 }

                 return result;

         }

         /**

          * This method does the actual comparison of the term value w/ the expected value

          *

          * @param termValue

          * @return the boolean result of the comparison

          */

         protected boolean compare(Comparable<T> termValue) {

                 boolean result = Boolean.valueOf(operator.compare(termValue, getExpectedValue()));

                 return result;

         }

         @Override

         public List<Proposition> getChildren() {

             return Collections.emptyList();

         }

         @Override

         public boolean isCompound() {

             return false;

         }

         /**

          * @return the expectedValue

          */

         protected T getExpectedValue() {

                 return this.expectedValue;

         }

         public String toString(){

                 StringBuilder sb = new StringBuilder();

                 sb.append(term.toString());

                 sb.append(" "+operator.toString());

                 sb.append(" "+expectedValue.toString());

                 return sb.toString();

         }

 }