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.Map;
19
20 import org.kuali.rice.krms.api.engine.ExecutionOptions;
21 import org.kuali.rice.krms.api.engine.SelectionCriteria;
22 import org.kuali.rice.krms.api.engine.Term;
23
24 /**
25 * Loads a {@link Context} for the given set of criteria. Applications who
26 * want to provide their own means for creating a context and supplying it to
27 * the KRMS engine can do so by implementing a custom ContextProvider.
28 *
29 * @see Context
30 *
31 * @author Kuali Rice Team (rice.collab@kuali.org)
32 *
33 */
34 public interface ContextProvider {
35
36 /**
37 * Loads the context for the given selection criteria, facts, and execution
38 * options. If no context can be located based on the given criteria, then
39 * this method should return null.
40 *
41 * <p>In the case where multiple Contexts could potentially be identified
42 * from the same set of selection criteria, it is up to the implementer
43 * of the ContextProvider to ensure that the most appropriate Context is
44 * returned. Or alternatively, an exception could be thrown indicating
45 * context ambiguity.
46 *
47 * <p>The sectionCriteria, facts, and executionOptions which are passed to
48 * this method should never be null. However, they might be empty.
49 *
50 * @param selectionCriteria the criteria to use during the selection phase of engine operation
51 * @param facts the set of facts that are supplied to the engine at execution time
52 * @param executionOptions a collection of options that can be used to customize engine execution behavior
53 *
54 * @return the context which matches the given criteria, or null if no context matches
55 */
56 public Context loadContext(SelectionCriteria selectionCriteria, Map<Term, Object> facts, ExecutionOptions executionOptions);
57
58 }