001    /**
002     * Copyright 2005-2014 The Kuali Foundation
003     *
004     * Licensed under the Educational Community License, Version 2.0 (the "License");
005     * you may not use this file except in compliance with the License.
006     * You may obtain a copy of the License at
007     *
008     * http://www.opensource.org/licenses/ecl2.php
009     *
010     * Unless required by applicable law or agreed to in writing, software
011     * distributed under the License is distributed on an "AS IS" BASIS,
012     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013     * See the License for the specific language governing permissions and
014     * limitations under the License.
015     */
016    package org.kuali.rice.krms.framework.engine.expression;
017    
018    import java.util.Collections;
019    import java.util.List;
020    
021    import org.kuali.rice.krms.api.engine.ExecutionEnvironment;
022    import org.kuali.rice.krms.framework.engine.Proposition;
023    import org.kuali.rice.krms.framework.engine.PropositionResult;
024    
025    /**
026     * An implementation of {@link Proposition} which uses a given {@link Expression}<Boolean>
027     * @author Kuali Rice Team (rice.collab@kuali.org)
028     *
029     */
030    public class ExpressionBasedProposition implements Proposition {
031    
032            private final Expression<Boolean> expression;
033    
034        /**
035         * Create an ExpressionBasedProposition with the given value
036         * @param expression {@link Expression} to set the expression to
037         */
038            public ExpressionBasedProposition(Expression<Boolean> expression) {
039                    this.expression = expression;
040            }
041            
042            @Override
043            public PropositionResult evaluate(ExecutionEnvironment environment) {
044                    return new PropositionResult(expression.invoke(environment).booleanValue());
045            }
046    
047    
048        @Override
049        public List<Proposition> getChildren() {
050            return Collections.emptyList();
051        }
052        
053        @Override
054        public boolean isCompound() {
055            return false;
056        }
057    }