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;
17
18 import java.util.List;
19
20 import org.kuali.rice.krms.api.engine.Engine;
21 import org.kuali.rice.krms.api.engine.ExecutionEnvironment;
22
23 /**
24 * Interface for logical propositions that may be executed in the {@link Engine}.
25 * @see PropositionResult
26 * @author Kuali Rice Team (rice.collab@kuali.org)
27 */
28 public interface Proposition {
29
30 /**
31 * Evaluates this proposition -- and in the case of {@link Proposition}s containing children,
32 * those children as well -- and returns the boolean result;
33 *
34 * @param environment the {@link ExecutionEnvironment} that this {@link Proposition} is running in
35 * @return the boolean result of evaluation
36 */
37 public PropositionResult evaluate(ExecutionEnvironment environment);
38
39 /**
40 * Returns the {@link List} of child {@link Proposition}s that belong to this object.
41 * If there are no children (e.g. for simple {@link Proposition} types), this must
42 * return an empty {@link List}.
43 *
44 * @return a {@link List} containing any child {@link Proposition}s that belong to this object. Must never return null.
45 */
46 public List<Proposition> getChildren();
47
48 /**
49 * Indicates whether this {@link Proposition} can have children.
50 * @return true if this {@link Proposition} can contain child {@link Proposition}s.
51 */
52 public boolean isCompound();
53
54 }