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.jexl3.scripting;
019
020import java.io.BufferedReader;
021import java.io.File;
022import java.io.FileInputStream;
023import java.io.InputStreamReader;
024
025import java.nio.charset.Charset;
026import javax.script.ScriptEngine;
027import javax.script.ScriptException;
028
029/**
030 * Test application for JexlScriptEngine (JSR-223 implementation).
031 *
032 * @since 2.0
033 */
034public class Main {
035
036    /**
037     * Reads an input.
038     *
039     * @param charset the charset or null for default charset
040     * @param fileName the file name or null for stdin
041     * @return the reader
042     * @throws Exception if anything goes wrong
043     */
044    static BufferedReader read(final Charset charset, final String fileName) throws Exception {
045        return new BufferedReader(
046            new InputStreamReader(
047                    fileName == null
048                        ? System.in
049                        : new FileInputStream(new File(fileName)),
050                    charset == null
051                        ? Charset.defaultCharset()
052                        : charset));
053    }
054
055    /**
056     * Test application for JexlScriptEngine (JSR-223 implementation).
057     *
058     * If a single argument is present, it is treated as a file name of a JEXL
059     * script to be evaluated. Any exceptions terminate the application.
060     *
061     * Otherwise, lines are read from standard input and evaluated.
062     * ScriptExceptions are logged, and do not cause the application to exit.
063     * This is done so that interactive testing is easier.
064     *
065     * @param args (optional) file name to evaluate. Stored in the args variable.
066     *
067     * @throws Exception if parsing or IO fail
068     */
069    public static void main(final String[] args) throws Exception {
070        final JexlScriptEngineFactory fac = new JexlScriptEngineFactory();
071        final ScriptEngine engine = fac.getScriptEngine();
072        engine.put("args", args);
073        if (args.length == 1){
074            final Object value = engine.eval(read(null, args[0]));
075            System.out.println("Return value: "+value);
076        } else {
077            final BufferedReader console = read(null, null);
078            String line;
079            System.out.print("> ");
080            while(null != (line=console.readLine())){
081                try {
082                    final Object value = engine.eval(line);
083                    System.out.println("Return value: "+value);
084                } catch (final ScriptException e) {
085                    System.out.println(e.getLocalizedMessage());
086                }
087                System.out.print("> ");
088            }
089        }
090    }
091}