/*

  * Copyright 2011 The Kuali Foundation

  *

  * Licensed under the Educational Community License, Version 1.0 (the "License");

  * you may not use this file except in compliance with the License.

  * You may obtain a copy of the License at

  *

  * http://www.opensource.org/licenses/ecl1.php

  *

  * Unless required by applicable law or agreed to in writing, software

  * distributed under the License is distributed on an "AS IS" BASIS,

  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

  * See the License for the specific language governing permissions and

  * limitations under the License.

  */

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

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

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

 /**

  * TODO... 

  * 

  * @author Kuali Rice Team (rice.collab@kuali.org)

  *

  */

 public final class BooleanValidatingExpression implements Expression<Boolean> {

         private final Expression<? extends Object> expression;

         public BooleanValidatingExpression(Expression<? extends Object> expression) {

                 this.expression = expression;

         }

         public Boolean invoke(ExecutionEnvironment environment) {

                 Object result = expression.invoke(environment);

                 if (result instanceof Boolean) {

                         return (Boolean)result;

                 }

                 throw new IncompatibleTypeException("Type mismatch when executing expression.", result, Boolean.class);

         }

 }