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1   /**
2    * Copyright 2005-2012 The Kuali Foundation
3    *
4    * Licensed under the Educational Community License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    *
8    * http://www.opensource.org/licenses/ecl2.php
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  package org.kuali.rice.krms.framework.engine.expression;
17  
18  import java.util.Collections;
19  import java.util.List;
20  
21  import org.kuali.rice.krms.api.engine.ExecutionEnvironment;
22  import org.kuali.rice.krms.framework.engine.Proposition;
23  import org.kuali.rice.krms.framework.engine.PropositionResult;
24  
25  /**
26   * An implementation of {@link Proposition} which uses a given {@link Expression}<Boolean>
27   * @author Kuali Rice Team (rice.collab@kuali.org)
28   *
29   */
30  public class ExpressionBasedProposition implements Proposition {
31  
32  	private final Expression<Boolean> expression;
33  
34      /**
35       * Create an ExpressionBasedProposition with the given value
36       * @param expression {@link Expression} to set the expression to
37       */
38  	public ExpressionBasedProposition(Expression<Boolean> expression) {
39  		this.expression = expression;
40  	}
41  	
42  	@Override
43  	public PropositionResult evaluate(ExecutionEnvironment environment) {
44  		return new PropositionResult(expression.invoke(environment).booleanValue());
45  	}
46  
47  
48      @Override
49      public List<Proposition> getChildren() {
50          return Collections.emptyList();
51      }
52      
53      @Override
54      public boolean isCompound() {
55          return false;
56      }
57  }