Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||
ExpressionEvaluator |
|
| 1.0;1 |
1 | // Copyright 2004, 2005 The Apache Software Foundation | |
2 | // | |
3 | // Licensed under the Apache License, Version 2.0 (the "License"); | |
4 | // you may not use this file except in compliance with the License. | |
5 | // You may obtain a copy of the License at | |
6 | // | |
7 | // http://www.apache.org/licenses/LICENSE-2.0 | |
8 | // | |
9 | // Unless required by applicable law or agreed to in writing, software | |
10 | // distributed under the License is distributed on an "AS IS" BASIS, | |
11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
12 | // See the License for the specific language governing permissions and | |
13 | // limitations under the License. | |
14 | ||
15 | package org.apache.tapestry.services; | |
16 | ||
17 | import ognl.OgnlContext; | |
18 | import ognl.enhance.ExpressionAccessor; | |
19 | ||
20 | /** | |
21 | * Wrapper around the OGNL library. | |
22 | * | |
23 | * @author Howard M. Lewis Ship | |
24 | * @since 4.0 | |
25 | */ | |
26 | public interface ExpressionEvaluator | |
27 | { | |
28 | ||
29 | /** | |
30 | * Reads a property of the target, defined by the expression. | |
31 | * | |
32 | * @throws org.apache.hivemind.ApplicationRuntimeException | |
33 | * if the expression can not be parsed, or if some other error | |
34 | * occurs during evaluation of the expression. | |
35 | */ | |
36 | Object read(Object target, String expression); | |
37 | ||
38 | /** | |
39 | * Reads a property of the target, defined by the (previously compiled) | |
40 | * expression. | |
41 | * | |
42 | * @throws org.apache.hivemind.ApplicationRuntimeException | |
43 | * if some other error occurs during evaluation of the | |
44 | * expression. | |
45 | */ | |
46 | Object readCompiled(Object target, Object expression); | |
47 | ||
48 | /** | |
49 | * Reads a property of the target, defined by the (previously compiled) | |
50 | * expression. | |
51 | * | |
52 | * @param target | |
53 | * The object to resolve the expression against. | |
54 | * @param expression | |
55 | * The compiled expression. | |
56 | * @return | |
57 | * The result of reading on the expression. | |
58 | */ | |
59 | Object read(Object target, ExpressionAccessor expression); | |
60 | ||
61 | /** | |
62 | * Updates a property of the target, defined by the expression. | |
63 | * | |
64 | * @throws org.apache.hivemind.ApplicationRuntimeException | |
65 | * if the expression can not be parsed, or if some other error | |
66 | * occurs during evaluation of the expression. | |
67 | */ | |
68 | void write(Object target, String expression, Object value); | |
69 | ||
70 | /** | |
71 | * Updates a property of the target, defined by the (previously compiled) | |
72 | * expression. | |
73 | * | |
74 | * @throws org.apache.hivemind.ApplicationRuntimeException | |
75 | * if some other error occurs during evaluation of the | |
76 | * expression. | |
77 | */ | |
78 | void writeCompiled(Object target, Object expression, Object value); | |
79 | ||
80 | /** | |
81 | * Updates a property of the target, defined by the (previously compiled) | |
82 | * expression. | |
83 | * | |
84 | * @param target | |
85 | * The target object to set a value on. | |
86 | * @param expression | |
87 | * The pre-compiled expression. | |
88 | * @param value | |
89 | * The value to set. | |
90 | */ | |
91 | void write(Object target, ExpressionAccessor expression, Object value); | |
92 | ||
93 | /** | |
94 | * Returns true if the expression evaluates to a constant or other literal | |
95 | * value. | |
96 | * | |
97 | * @throws org.apache.hivemind.ApplicationRuntimeException | |
98 | * if the expression is not valid | |
99 | */ | |
100 | boolean isConstant(String expression); | |
101 | ||
102 | /** | |
103 | * Returns true if the expression evaluates to a constant or other literal | |
104 | * value. | |
105 | * | |
106 | * @throws org.apache.hivemind.ApplicationRuntimeException | |
107 | * if the expression is not valid | |
108 | */ | |
109 | boolean isConstant(Object target, String expression); | |
110 | ||
111 | /** | |
112 | * Creates a default OGNL context object that can be used against | |
113 | * the specified object for expression evaluation. | |
114 | * | |
115 | * @param target | |
116 | * The object to get a context for. | |
117 | * @return | |
118 | * An ognl context map. | |
119 | */ | |
120 | OgnlContext createContext(Object target); | |
121 | } |