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.ArrayList;
19 import java.util.List;
20
21 import org.kuali.rice.krms.api.engine.ExecutionEnvironment;
22 import org.kuali.rice.krms.framework.engine.Function;
23
24 /**
25 * An implementation of {@link Expression} which invokes a {@link Function} with the results of the invocation of the given
26 * List of {@link Expression}s (of the given {@link ExecutionEnvironment}).
27 * @author Kuali Rice Team (rice.collab@kuali.org)
28 *
29 */
30 public final class FunctionExpression implements Expression<Object> {
31
32 private final Function function;
33 private final List<Expression<? extends Object>> arguments;
34
35 /**
36 * Create a FunctionExpression with the given values.
37 * @param function {@link Function} to be invoked using the invoked results of the given List of {@link Expression}s
38 * @param arguments List of {@link Expression}s to be invoked whose results (of the given {@link ExecutionEnvironment})
39 * will be used to invoke the given {@link Function}.
40 */
41 public FunctionExpression(Function function,
42 List<Expression<? extends Object>> arguments) {
43 this.function = function;
44 this.arguments = arguments;
45 }
46
47 @Override
48 public Object invoke(ExecutionEnvironment environment) {
49 List<Object> argumentValues = new ArrayList<Object>(arguments.size());
50 for (Expression<? extends Object> argument : arguments) {
51 argumentValues.add(argument.invoke(environment));
52 }
53 return function.invoke(argumentValues);
54 }
55
56 }