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1   /*
2    * Copyright 2007-2013 smartics, Kronseder & Reiner GmbH
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  package de.smartics.exceptions.ognl;
17  
18  import ognl.Ognl;
19  import ognl.OgnlContext;
20  import ognl.OgnlException;
21  
22  /**
23   * Wrapper for an OGNL expression.
24   */
25  public final class OgnlExpression
26  {
27    // ********************************* Fields *********************************
28  
29    // --- constants ------------------------------------------------------------
30  
31    // --- members --------------------------------------------------------------
32  
33    /**
34     * The reference to the parsed expression instance.
35     */
36    private final Object expression;
37  
38    // ****************************** Initializer *******************************
39  
40    // ****************************** Constructors ******************************
41  
42    /**
43     * Default constructor.
44     *
45     * @param expressionString the OGNL expression to parse.
46     * @throws OgnlException on any parsing problem.
47     */
48    public OgnlExpression(final String expressionString) throws OgnlException
49    {
50      expression = Ognl.parseExpression(expressionString);
51    }
52  
53    // ****************************** Inner Classes *****************************
54  
55    // ********************************* Methods ********************************
56  
57    // --- init -----------------------------------------------------------------
58  
59    // --- get&set --------------------------------------------------------------
60  
61    /**
62     * Returns the reference to the parsed expression instance.
63     *
64     * @return the reference to the parsed expression instance.
65     */
66    public Object getExpression()
67    {
68      return expression;
69    }
70  
71    // --- business -------------------------------------------------------------
72  
73    /**
74     * Returns the value for the given context on the given root object.
75     *
76     * @param context the context of the evaluation.
77     * @param rootObject the root object to run the evaluation of the OGNL
78     *          expression.
79     * @return the value of the root object referenced by the OGNL expression.
80     * @throws OgnlException on any problem encountered fetching the value.
81     */
82    public Object getValue(final OgnlContext context, final Object rootObject)
83      throws OgnlException
84    {
85      return Ognl.getValue(getExpression(), context, rootObject);
86    }
87  
88    /**
89     * Sets the value dependent on the OGNL expression.
90     *
91     * @param context the context of the evaluation.
92     * @param rootObject the root object to run the evaluation of the OGNL
93     *          expression.
94     * @param value the value to set.
95     * @throws OgnlException on any problem encountered setting the value.
96     */
97    public void setValue(final OgnlContext context, final Object rootObject,
98        final Object value) throws OgnlException
99    {
100     Ognl.setValue(getExpression(), context, rootObject, value);
101   }
102 
103   // --- object basics --------------------------------------------------------
104 
105 }