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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  package org.apache.commons.jexl3;
18  
19  import org.apache.commons.jexl3.introspection.JexlPropertyGet;
20  import org.apache.commons.jexl3.introspection.JexlPropertySet;
21  
22  /**
23   * Wraps an Object as a JEXL context and NamespaceResolver.
24   *
25   * @param <T> the wrapped object type to use
26   * @since 3.0
27   */
28  public class ObjectContext<T> implements JexlContext, JexlContext.NamespaceResolver {
29  
30      /** The property solving jexl engine. */
31      private final JexlEngine jexl;
32  
33      /** The object serving as context provider. */
34      private final T object;
35  
36      /**
37       * @return the Jexl engine
38       */
39      protected JexlEngine getJexl() {
40          return jexl;
41      }
42  
43      /**
44       * @return the object exposed by this context
45       */
46      protected T getObject() {
47          return object;
48      }
49  
50      /**
51       * Creates a new ObjectContext.
52       *
53       * @param engine  the jexl engine to use to solve properties
54       * @param wrapped the object to wrap in this context
55       */
56      public ObjectContext(final JexlEngine engine, final T wrapped) {
57          this.jexl = engine;
58          this.object = wrapped;
59      }
60  
61      @Override
62      public Object get(final String name) {
63          final JexlPropertyGet jget = jexl.getUberspect().getPropertyGet(object, name);
64          if (jget != null) {
65              try {
66                  return jget.invoke(object);
67              } catch (final Exception xany) {
68                  if (jexl.isStrict()) {
69                      throw new JexlException.Property(null, name, true, xany);
70                  }
71              }
72          }
73          return null;
74      }
75  
76      @Override
77      public void set(final String name, final Object value) {
78          final JexlPropertySet jset = jexl.getUberspect().getPropertySet(object, name, value);
79          if (jset != null) {
80              try {
81                  jset.invoke(object, value);
82              } catch (final Exception xany) {
83                  // ignore
84                  if (jexl.isStrict()) {
85                      throw new JexlException.Property(null, name, true, xany);
86                  }
87              }
88          }
89      }
90  
91      @Override
92      public boolean has(final String name) {
93          return jexl.getUberspect().getPropertyGet(object, name) != null;
94      }
95  
96      @Override
97      public Object resolveNamespace(final String name) {
98          if (name == null || name.isEmpty()) {
99              return object;
100         }
101         return null;
102     }
103 }