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