JexlContextMap


1   /*
2    * Copyright 2006-2007 The Scriptella Project Team.
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 scriptella.driver.jexl;
17  
18  import org.apache.commons.jexl.JexlContext;
19  import scriptella.spi.ParametersCallback;
20  
21  import java.util.Collection  ;
22  import java.util.HashMap  ;
23  import java.util.Map  ;
24  import java.util.Set  ;
25  
26  /**
27   * Mutable {@link org.apache.commons.jexl.JexlContext} implementation for
28   * integration into Scriptella execution environment.
29   * This class allows local variables to be set via {@link #put(String,Object)} method.
30   * <br>{@link #getParameter(String)} allows reading variables.
31   *
32   * @author Fyodor Kupolov
33   * @version 1.0
34   */
35  public final class JexlContextMap implements ParametersCallback, JexlContext, Map  <String  , Object  > {
36      private Map  <String  , Object  > localVariables = new HashMap  <String  , Object  >();
37      private ParametersCallback parentParameters;
38  
39  
40      /**
41       * Initializes instance and set parent parameters to use in {@link #getParameter(String)}.
42       *
43       * @param parentParameters parent parameters.
44       */
45      public JexlContextMap(ParametersCallback parentParameters) {
46          this.parentParameters = parentParameters;
47      }
48  
49      /**
50       * Returns specified variable value.
51       * <p>The local variables set by {@link #put(String,Object)} method
52       * take priority of variables in parentParameters object.
53       *
54       * @param name variable name
55       * @return value of variable or null if variable not found.
56       */
57      public Object   getParameter(final String   name) {
58          Object   v = localVariables.get(name);
59          if (v != null) {
60              return v;
61          }
62          return parentParameters.getParameter(name);
63      }
64  
65      @SuppressWarnings  ("unchecked")
66      public void setVars(Map   vars) {
67          localVariables.clear();
68          localVariables.putAll(vars);
69      }
70  
71      public Map  <String  , Object  > getVars() {
72          return this;
73      }
74  
75      /**
76       * Use {@link #getParameter(String)}.
77       * @param key variable name.
78       * @return value of variable.
79       */
80      public Object   get(Object   key) {
81          return (key instanceof String  ) ? getParameter((String  ) key) : null;
82      }
83  
84      /**
85       * Sets local variable.
86       * @param key variable name.
87       * @param value variable value.
88       * @return previous variable value.
89       */
90      public Object   put(String   key, Object   value) {
91          return localVariables.put(key, value);
92      }
93  
94      /**
95       * Removes local variable.
96       * @param key variable name.
97       * @return previous value.
98       */
99      public Object   remove(Object   key) {
100         return localVariables.remove(key);
101     }
102 
103     /**
104      * Registers local variables.
105      * @param t local variables map.
106      */
107     public void putAll(Map  <? extends String  , ?> t) {
108         localVariables.putAll(t);
109     }
110 
111     /**
112      * Clears local variables.
113      */
114     public void clear() {
115         localVariables.clear();
116     }
117 
118     //Unsupported operations
119 
120     public int size() {
121         throw new UnsupportedOperationException  ();
122     }
123 
124     public boolean isEmpty() {
125         throw new UnsupportedOperationException  ();
126     }
127 
128     public boolean containsKey(Object   key) {
129         throw new UnsupportedOperationException  ();
130     }
131 
132     public boolean containsValue(Object   value) {
133         throw new UnsupportedOperationException  ();
134     }
135 
136 
137     public Set  <String  > keySet() {
138         throw new UnsupportedOperationException  ();
139     }
140 
141     public Collection  <Object  > values() {
142         throw new UnsupportedOperationException  ();
143     }
144 
145     public Set  <Map.Entry  <String  , Object  >> entrySet() {
146         throw new UnsupportedOperationException  ();
147     }
148 }
149
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