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.List;
19
20 import org.kuali.rice.krms.api.engine.ExecutionEnvironment;
21 import org.kuali.rice.krms.api.engine.expression.ComparisonOperatorService;
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 String [] parameterTypes;
34 private final List<Expression<? extends Object>> parameters;
35 private final ComparisonOperatorService comparisonOperatorService;
36
37 /**
38 * Create a FunctionExpression with the given values.
39 * @param function {@link Function} to be invoked using the invoked results of the given List of {@link Expression}s
40 * @param parameterTypes the full class names for the function's parameter types in sequential order
41 * @param parameters List of {@link Expression}s to be invoked whose results (of the given {@link ExecutionEnvironment})
42 * @param comparisonOperatorService -- TODO:
43 * will be used to invoke the given {@link Function}.
44 */
45 public FunctionExpression(Function function, String[] parameterTypes,
46 List<Expression<? extends Object>> parameters,
47 ComparisonOperatorService comparisonOperatorService) {
48 this.function = function;
49 this.parameterTypes = parameterTypes;
50 this.parameters = parameters;
51 this.comparisonOperatorService = comparisonOperatorService;
52 }
53
54 @Override
55 public Object invoke(ExecutionEnvironment environment) {
56 Object[] argumentValues = new Object[parameters.size()];
57
58 int argValIndex = 0;
59
60 for (Expression<? extends Object> argument : parameters) {
61 Object argumentValue = argument.invoke(environment);
62 String expectedArgumentType = parameterTypes[argValIndex];
63
64 argumentValue = ComparisonOperatorServiceUtils.coerceIfNeeded(argumentValue, expectedArgumentType, comparisonOperatorService);
65
66 argumentValues[argValIndex] = argumentValue;
67 argValIndex += 1;
68 }
69
70 return function.invoke(argumentValues);
71 }
72
73
74 }