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.scripting;
19
20 import java.io.BufferedReader;
21 import java.io.File;
22 import java.io.FileInputStream;
23 import java.io.InputStreamReader;
24 import java.io.PrintStream;
25 import java.nio.charset.Charset;
26
27 import javax.script.ScriptEngine;
28 import javax.script.ScriptException;
29
30 /**
31 * Test application for JexlScriptEngine (JSR-223 implementation).
32 *
33 * @since 2.0
34 */
35 public class Main {
36
37 /**
38 * Test application for JexlScriptEngine (JSR-223 implementation).
39 *
40 * If a single argument is present, it is treated as a file name of a JEXL
41 * script to be evaluated. Any exceptions terminate the application.
42 *
43 * Otherwise, lines are read from standard input and evaluated.
44 * ScriptExceptions are logged, and do not cause the application to exit.
45 * This is done so that interactive testing is easier.
46 *
47 * @param args (optional) file name to evaluate. Stored in the args variable.
48 *
49 * @throws Exception if parsing or IO fail
50 */
51 public static void main(final String[] args) throws Exception {
52 final JexlScriptEngineFactory fac = new JexlScriptEngineFactory();
53 final ScriptEngine engine = fac.getScriptEngine();
54 final PrintStream out = System.out;
55 engine.put("args", args);
56 if (args.length == 1){
57 final Object value = engine.eval(read(null, args[0]));
58 out.println("Return value: "+value);
59 } else {
60 final BufferedReader console = read(null, null);
61 String line;
62 System.out.print("> ");
63 while(null != (line=console.readLine())){
64 try {
65 final Object value = engine.eval(line);
66 out.println("Return value: "+value);
67 } catch (final ScriptException e) {
68 out.println(e.getLocalizedMessage());
69 }
70 out.print("> ");
71 }
72 }
73 }
74
75 /**
76 * Reads an input.
77 *
78 * @param charset the charset or null for default charset
79 * @param fileName the file name or null for stdin
80 * @return the reader
81 * @throws Exception if anything goes wrong
82 */
83 static BufferedReader read(final Charset charset, final String fileName) throws Exception {
84 return new BufferedReader(
85 new InputStreamReader(
86 fileName == null
87 ? System.in
88 : new FileInputStream(new File(fileName)),
89 charset == null
90 ? Charset.defaultCharset()
91 : charset));
92 }
93 }