001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018package org.apache.commons.jexl2.scripting;
019
020import java.io.BufferedReader;
021import java.io.FileReader;
022import java.io.InputStreamReader;
023
024import javax.script.ScriptEngine;
025import javax.script.ScriptException;
026
027/**
028 * Test application for JexlScriptEngine (JSR-223 implementation).
029 * @since 2.0
030 */
031public class Main {
032
033    /**
034     * Test application for JexlScriptEngine (JSR-223 implementation).
035     * 
036     * If a single argument is present, it is treated as a filename of a JEXL
037     * script to be evaluated. Any exceptions terminate the application.
038     * 
039     * Otherwise, lines are read from standard input and evaluated.
040     * ScriptExceptions are logged, and do not cause the application to exit.
041     * This is done so that interactive testing is easier.
042     * 
043     * @param args (optional) filename to evaluate. Stored in the args variable.
044     * 
045     * @throws Exception if parsing or IO fail
046     */
047    public static void main(String[] args) throws Exception {
048        JexlScriptEngineFactory fac = new JexlScriptEngineFactory();
049        ScriptEngine engine = fac.getScriptEngine();
050        engine.put("args", args);
051        if (args.length == 1){
052            Object value = engine.eval(new FileReader(args[0]));
053            System.out.println("Return value: "+value);
054        } else {
055            BufferedReader console = new BufferedReader(new InputStreamReader(System.in));
056            String line;
057            System.out.print("> ");
058            while(null != (line=console.readLine())){
059                try {
060                    Object value = engine.eval(line);
061                    System.out.println("Return value: "+value);
062                } catch (ScriptException e) {
063                    System.out.println(e.getLocalizedMessage());
064                }
065                System.out.print("> ");
066            }
067        }
068    }
069}