    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 *      https://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.util.Arrays;
    021import java.util.Collections;
    022import java.util.List;
    023
    024import javax.script.ScriptEngine;
    025import javax.script.ScriptEngineFactory;
    026
    027import org.apache.commons.jexl3.parser.StringParser;
    028
    029/**
    030 * Implements the JEXL ScriptEngineFactory for JSF-223.
    031 * <p>
    032 * Supports the following:<br>
    033 * </p>
    034 * <ul>
    035 * <li>Language short names: "JEXL", "Jexl", "jexl", "JEXL2", "Jexl2", "jexl2", "JEXL3", "Jexl3", "jexl3"</li>
    036 * <li>File Extensions: ".jexl", ".jexl2", ".jexl3"</li>
    037 * <li>"jexl3" etc. were added for engineVersion="3.0"</li>
    038 * </ul>
    039 * <p>
    040 * See
    041 * <a href="https://java.sun.com/javase/6/docs/api/javax/script/package-summary.html">Java Scripting API</a>
    042 * Javadoc.
    043 *
    044 * @since 2.0
    045 */
    046public class JexlScriptEngineFactory implements ScriptEngineFactory {
    047
    048    /** Default constructor */
    049    public JexlScriptEngineFactory() {} // Keep Javadoc happy
    050
    051    @Override
    052    public String getEngineName() {
    053        return "JEXL Engine";
    054    }
    055
    056    @Override
    057    public String getEngineVersion() {
    058        return "3.6"; // ensure this is updated if function changes are made to this class
    059    }
    060
    061    @Override
    062    public List<String> getExtensions() {
    063        return Collections.unmodifiableList(Arrays.asList("jexl", "jexl2", "jexl3"));
    064    }
    065
    066    @Override
    067    public String getLanguageName() {
    068        return "JEXL";
    069    }
    070
    071    @Override
    072    public String getLanguageVersion() {
    073        return "3.6"; // this should be derived from the actual version
    074    }
    075
    076    @Override
    077    public String getMethodCallSyntax(final String obj, final String m, final String... args) {
    078        final StringBuilder sb = new StringBuilder();
    079        sb.append(obj);
    080        sb.append('.');
    081        sb.append(m);
    082        sb.append('(');
    083        boolean needComma = false;
    084        for(final String arg : args){
    085            if (needComma) {
    086                sb.append(',');
    087            }
    088            sb.append(arg);
    089            needComma = true;
    090        }
    091        sb.append(')');
    092        return sb.toString();
    093    }
    094
    095    @Override
    096    public List<String> getMimeTypes() {
    097        return Collections.unmodifiableList(Arrays.asList("application/x-jexl",
    098                                                          "application/x-jexl2",
    099                                                          "application/x-jexl3"));
    100    }
    101
    102    @Override
    103    public List<String> getNames() {
    104        return Collections.unmodifiableList(Arrays.asList("JEXL", "Jexl", "jexl",
    105                                                          "JEXL2", "Jexl2", "jexl2",
    106                                                          "JEXL3", "Jexl3", "jexl3"));
    107    }
    108
    109    @Override
    110    public String getOutputStatement(final String toDisplay) {
    111        if (toDisplay == null) {
    112            return "JEXL.out.print(null)";
    113        }
    114        return "JEXL.out.print("+StringParser.escapeString(toDisplay, '\'')+")";
    115    }
    116
    117    @Override
    118    public Object getParameter(final String key) {
    119        switch (key) {
    120            case ScriptEngine.ENGINE:
    121                return getEngineName();
    122            case ScriptEngine.ENGINE_VERSION:
    123                return getEngineVersion();
    124            case ScriptEngine.NAME:
    125                return getNames();
    126            case ScriptEngine.LANGUAGE:
    127                return getLanguageName();
    128            case ScriptEngine.LANGUAGE_VERSION:
    129                return getLanguageVersion();
    130            case "THREADING":
    131                /*
    132                 * To implement multithreading, the scripting engine context (inherited from AbstractScriptEngine)
    133                 * would need to be made thread-safe; so would the setContext/getContext methods.
    134                 * It is easier to share the underlying Uberspect and JEXL engine instance, especially
    135                 * with an expression cache.
    136                 */
    137            default:
    138                return null;
    139        }
    140    }
    141
    142    @Override
    143    public String getProgram(final String... statements) {
    144        final StringBuilder sb = new StringBuilder();
    145        for(final String statement : statements){
    146            sb.append(statement.trim());
    147            if (!statement.endsWith(";")){
    148                sb.append(';');
    149            }
    150        }
    151        return sb.toString();
    152    }
    153
    154    @Override
    155    public ScriptEngine getScriptEngine() {
    156        return new JexlScriptEngine(this);
    157    }
    158
    159}