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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  
18  package org.apache.commons.jexl2;
19  
20  import java.io.BufferedReader;
21  import java.io.File;
22  import java.io.InputStreamReader;
23  
24  /**
25   * Test application for JEXL.
26   *
27   * @since 2.0
28   */
29  public class Main {
30      /**
31       * Test application for JEXL
32       * 
33       * If a single argument is present, it is treated as a filename of a JEXL
34       * script to be executed as a script. Any exceptions terminate the application.
35       * 
36       * Otherwise, lines are read from standard input and evaluated.
37       * ParseExceptions and JexlExceptions are logged, and do not cause the application to exit.
38       * This is done so that interactive testing is easier.
39       * 
40       * @param args (optional) filename to execute. Stored in the args variable.
41       * 
42       * @throws Exception if parsing or IO fail
43       */
44      public static void main(String[] args) throws Exception {
45          JexlEngine engine = new JexlEngine();
46          JexlContext context = new MapContext();
47          context.set("args", args);
48          if (args.length == 1) {
49              Script script = engine.createScript(new File(args[0]));
50              Object value = script.execute(context);
51              System.out.println("Return value: " + value);
52          } else {
53              BufferedReader console = new BufferedReader(new InputStreamReader(System.in));
54              String line;
55              System.out.print("> ");
56              while (null != (line = console.readLine())) {
57                  try {
58                      Expression expression = engine.createExpression(line);
59                      Object value = expression.evaluate(context);
60                      System.out.println("Return value: " + value);
61                  } catch (JexlException e) {
62                      System.out.println(e.getLocalizedMessage());
63                  }
64                  System.out.print("> ");
65              }
66          }
67      }
68  }