    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.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 * Language short names: "JEXL", "Jexl", "jexl", "JEXL2", "Jexl2", "jexl2", "JEXL3", "Jexl3", "jexl3" <br>
    034 * File Extensions: ".jexl", ".jexl2", ".jexl3"<br>
    035 * "jexl3" etc. were added for engineVersion="3.0".
    036 * </p>
    037 * <p>
    038 * See
    039 * <a href="https://java.sun.com/javase/6/docs/api/javax/script/package-summary.html">Java Scripting API</a>
    040 * Javadoc.
    041 *
    042 * @since 2.0
    043 */
    044public class JexlScriptEngineFactory implements ScriptEngineFactory {
    045
    046    /** Default constructor */
    047    public JexlScriptEngineFactory() {} // Keep Javadoc happy
    048
    049    @Override
    050    public String getEngineName() {
    051        return "JEXL Engine";
    052    }
    053
    054    @Override
    055    public String getEngineVersion() {
    056        return "3.5"; // ensure this is updated if function changes are made to this class
    057    }
    058
    059    @Override
    060    public List<String> getExtensions() {
    061        return Collections.unmodifiableList(Arrays.asList("jexl", "jexl2", "jexl3"));
    062    }
    063
    064    @Override
    065    public String getLanguageName() {
    066        return "JEXL";
    067    }
    068
    069    @Override
    070    public String getLanguageVersion() {
    071        return "3.5"; // this should be derived from the actual version
    072    }
    073
    074    @Override
    075    public String getMethodCallSyntax(final String obj, final String m, final String... args) {
    076        final StringBuilder sb = new StringBuilder();
    077        sb.append(obj);
    078        sb.append('.');
    079        sb.append(m);
    080        sb.append('(');
    081        boolean needComma = false;
    082        for(final String arg : args){
    083            if (needComma) {
    084                sb.append(',');
    085            }
    086            sb.append(arg);
    087            needComma = true;
    088        }
    089        sb.append(')');
    090        return sb.toString();
    091    }
    092
    093    @Override
    094    public List<String> getMimeTypes() {
    095        return Collections.unmodifiableList(Arrays.asList("application/x-jexl",
    096                                                          "application/x-jexl2",
    097                                                          "application/x-jexl3"));
    098    }
    099
    100    @Override
    101    public List<String> getNames() {
    102        return Collections.unmodifiableList(Arrays.asList("JEXL", "Jexl", "jexl",
    103                                                          "JEXL2", "Jexl2", "jexl2",
    104                                                          "JEXL3", "Jexl3", "jexl3"));
    105    }
    106
    107    @Override
    108    public String getOutputStatement(final String toDisplay) {
    109        if (toDisplay == null) {
    110            return "JEXL.out.print(null)";
    111        }
    112        return "JEXL.out.print("+StringParser.escapeString(toDisplay, '\'')+")";
    113    }
    114
    115    @Override
    116    public Object getParameter(final String key) {
    117        switch (key) {
    118            case ScriptEngine.ENGINE:
    119                return getEngineName();
    120            case ScriptEngine.ENGINE_VERSION:
    121                return getEngineVersion();
    122            case ScriptEngine.NAME:
    123                return getNames();
    124            case ScriptEngine.LANGUAGE:
    125                return getLanguageName();
    126            case ScriptEngine.LANGUAGE_VERSION:
    127                return getLanguageVersion();
    128            case "THREADING":
    129                /*
    130                 * To implement multithreading, the scripting engine context (inherited from AbstractScriptEngine)
    131                 * would need to be made thread-safe; so would the setContext/getContext methods.
    132                 * It is easier to share the underlying Uberspect and JEXL engine instance, especially
    133                 * with an expression cache.
    134                 */
    135            default:
    136                return null;
    137        }
    138    }
    139
    140    @Override
    141    public String getProgram(final String... statements) {
    142        final StringBuilder sb = new StringBuilder();
    143        for(final String statement : statements){
    144            sb.append(statement.trim());
    145            if (!statement.endsWith(";")){
    146                sb.append(';');
    147            }
    148        }
    149        return sb.toString();
    150    }
    151
    152    @Override
    153    public ScriptEngine getScriptEngine() {
    154        return new JexlScriptEngine(this);
    155    }
    156
    157}