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.bean.rule.resolver;
18
19 import java.io.StringReader;
20 import java.util.Map;
21
22 import org.slf4j.Logger;
23 import org.slf4j.LoggerFactory;
24 import org.springmodules.validation.valang.functions.Function;
25 import org.springmodules.validation.valang.functions.TargetBeanFunction;
26 import org.springmodules.validation.valang.parser.ParseException;
27 import org.springmodules.validation.valang.parser.ValangParser;
28
29 /**
30 * Resolves error arguments based on valang expressions.
31 *
32 * @author Uri Boness
33 */
34 public class ValangErrorArgumentsResolver implements ErrorArgumentsResolver {
35
36 private final static Logger logger = LoggerFactory.getLogger(ValangErrorArgumentsResolver.class);
37
38 private Function[] functions;
39
40 /**
41 * Creates a new ValangErrorArgumentsResolver with no argument expressions, that is, there will be no arguments.
42 */
43 public ValangErrorArgumentsResolver() {
44 this(new String[0]);
45 }
46
47 /**
48 * Creates a new ValangErrorArgumentsResolver with the given argument expressions. This constructor uses the default
49 * {@link ValangParser).
50 *
51 * @param expressions The argument valang expressions.
52 */
53 public ValangErrorArgumentsResolver(String[] expressions) {
54 this(expressions, null);
55 }
56
57 /**
58 * Creates a new ValangErrorArgumentsResolver with given argument expressions and custom functions that will be used
59 * by the valang parser.
60 *
61 * @param expressions The arguments valang expressions.
62 * @param functionsByName A map of custom valang functiosns where the key is the function name and the value is
63 * the name of the function class.
64 */
65 public ValangErrorArgumentsResolver(String[] expressions, Map functionsByName) {
66 if (expressions == null) {
67 expressions = new String[0];
68 }
69 functions = new Function[expressions.length];
70 for (int i = 0; i < expressions.length; i++) {
71 functions[i] = parseFunction(expressions[i], functionsByName);
72 }
73 }
74
75 /**
76 * Returns the error arguments that are resolved by the configured valang expressions.
77 *
78 * @see org.springmodules.validation.bean.rule.resolver.ErrorArgumentsResolver#resolveArguments(Object)
79 */
80 public Object[] resolveArguments(Object obj) {
81 Object[] args = new Object[functions.length];
82 for (int i = 0; i < args.length; i++) {
83 args[i] = functions[i].getResult(obj);
84 }
85 return args;
86 }
87
88 //=============================================== Helper Methods ===================================================
89
90 /**
91 * Parses a valang {@link Function} from the given argument expression and custom functions.
92 *
93 * @param expression The given argument expression.
94 * @param functionsByName The custom valang functions.
95 * @return The parsed function.
96 */
97 protected Function parseFunction(String expression, Map functionsByName) {
98 ValangParser parser = new ValangParser(new StringReader(expression));
99 parser.setFunctionsByName(functionsByName);
100 try {
101 return parser.function(new TargetBeanFunction());
102 } catch (ParseException pe) {
103 logger.error("Could not parse valang expression '" + expression + "' to a function", pe);
104 throw new IllegalArgumentException("Could not parse valang expression '" + expression + "' to a function");
105 }
106 }
107
108 }