View Javadoc
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  
18  package org.apache.commons.jexl3;
19  
20  import java.util.HashMap;
21  import java.util.Map;
22  
23  /**
24   * Wraps a map in a context.
25   * <p>Each entry in the map is considered a variable name, value pair.</p>
26   */
27  public class MapContext implements JexlContext {
28  
29      /**
30       * The wrapped variable map.
31       */
32      private final Map<String, Object> map;
33  
34      /**
35       * Creates a MapContext on an automatically allocated underlying HashMap.
36       */
37      public MapContext() {
38          this(null);
39      }
40  
41      /**
42       * Creates a MapContext wrapping an existing user provided map.
43       *
44       * @param vars the variable map
45       */
46      public MapContext(final Map<String, Object> vars) {
47          map = vars == null ? new HashMap<>() : vars;
48      }
49  
50      @Override
51      public boolean has(final String name) {
52          return map.containsKey(name);
53      }
54  
55      @Override
56      public Object get(final String name) {
57          return map.get(name);
58      }
59  
60      @Override
61      public void set(final String name, final Object value) {
62          map.put(name, value);
63      }
64  
65      /**
66       * Clears all variables.
67       */
68      public void clear() {
69          map.clear();
70      }
71  }