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;
019
020import java.io.BufferedReader;
021import java.io.File;
022import java.io.InputStreamReader;
023
024/**
025 * Test application for JEXL.
026 *
027 * @since 2.0
028 */
029public class Main {
030    /**
031     * Test application for JEXL
032     * 
033     * If a single argument is present, it is treated as a filename of a JEXL
034     * script to be executed as a script. Any exceptions terminate the application.
035     * 
036     * Otherwise, lines are read from standard input and evaluated.
037     * ParseExceptions and JexlExceptions are logged, and do not cause the application to exit.
038     * This is done so that interactive testing is easier.
039     * 
040     * @param args (optional) filename to execute. Stored in the args variable.
041     * 
042     * @throws Exception if parsing or IO fail
043     */
044    public static void main(String[] args) throws Exception {
045        JexlEngine engine = new JexlEngine();
046        JexlContext context = new MapContext();
047        context.set("args", args);
048        if (args.length == 1) {
049            Script script = engine.createScript(new File(args[0]));
050            Object value = script.execute(context);
051            System.out.println("Return value: " + value);
052        } else {
053            BufferedReader console = new BufferedReader(new InputStreamReader(System.in));
054            String line;
055            System.out.print("> ");
056            while (null != (line = console.readLine())) {
057                try {
058                    Expression expression = engine.createExpression(line);
059                    Object value = expression.evaluate(context);
060                    System.out.println("Return value: " + value);
061                } catch (JexlException e) {
062                    System.out.println(e.getLocalizedMessage());
063                }
064                System.out.print("> ");
065            }
066        }
067    }
068}