1 /*
2 * Copyright 2004-2009 the original author or authors.
3 *
4 * Licensed under the Apache 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.apache.org/licenses/LICENSE-2.0
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
17 package org.springmodules.validation.util.fel.parser;
18
19 import org.springframework.beans.BeanWrapperImpl;
20 import org.springmodules.validation.util.fel.FelEvaluationException;
21 import org.springmodules.validation.util.fel.Function;
22 import org.springmodules.validation.util.fel.FunctionExpressionParser;
23
24 /**
25 * A {@link FunctionExpressionParser} implementation that knows how to parse BeanWrapper-like property paths and
26 * returns a function that extracts the appropriate property value from the given object (bean).
27 *
28 * @author Uri Boness
29 */
30 public class PropertyPathFunctionExpressionParser implements FunctionExpressionParser {
31
32 public Function parse(String expression) {
33 return new PropertyPathFunction(expression);
34 }
35
36 /**
37 * A function that is associated with a property path. On evaluation, the appropriate property value is
38 * extracted from the given object (bean).
39 */
40 protected class PropertyPathFunction implements Function {
41
42 private String propertyPath;
43
44 public PropertyPathFunction(String propertyPath) {
45 this.propertyPath = propertyPath;
46 }
47
48 public Object evaluate(Object argument) {
49 try {
50 return new BeanWrapperImpl(argument).getPropertyValue(propertyPath);
51 } catch (Throwable t) {
52 throw new FelEvaluationException("Could not evaluate path '" + propertyPath +
53 "' on bean '" + String.valueOf(argument) + "'", t);
54 }
55 }
56 }
57
58 }