    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;
    026import org.apache.commons.jexl3.parser.StringParser;
    027
    028/**
    029 * Implements the JEXL ScriptEngineFactory for JSF-223.
    030 * <p>
    031 * Supports the following:<br>
    032 * Language short names: "JEXL", "Jexl", "jexl", "JEXL2", "Jexl2", "jexl2", "JEXL3", "Jexl3", "jexl3" <br>
    033 * File Extensions: ".jexl", ".jexl2", ".jexl3"<br>
    034 * "jexl3" etc. were added for engineVersion="3.0".
    035 * </p>
    036 * <p>
    037 * See
    038 * <a href="http://java.sun.com/javase/6/docs/api/javax/script/package-summary.html">Java Scripting API</a>
    039 * Javadoc.
    040 *
    041 * @since 2.0
    042 */
    043public class JexlScriptEngineFactory implements ScriptEngineFactory {
    044
    045    @Override
    046    public String getEngineName() {
    047        return "JEXL Engine";
    048    }
    049
    050    @Override
    051    public String getEngineVersion() {
    052        return "3.2"; // ensure this is updated if function changes are made to this class
    053    }
    054
    055    @Override
    056    public String getLanguageName() {
    057        return "JEXL";
    058    }
    059
    060    @Override
    061    public String getLanguageVersion() {
    062        return "3.2"; // TODO this should be derived from the actual version
    063    }
    064
    065    @Override
    066    public String getMethodCallSyntax(final String obj, final String m, final String... args) {
    067        final StringBuilder sb = new StringBuilder();
    068        sb.append(obj);
    069        sb.append('.');
    070        sb.append(m);
    071        sb.append('(');
    072        boolean needComma = false;
    073        for(final String arg : args){
    074            if (needComma) {
    075                sb.append(',');
    076            }
    077            sb.append(arg);
    078            needComma = true;
    079        }
    080        sb.append(')');
    081        return sb.toString();
    082    }
    083
    084    @Override
    085    public List<String> getExtensions() {
    086        return Collections.unmodifiableList(Arrays.asList("jexl", "jexl2", "jexl3"));
    087    }
    088
    089    @Override
    090    public List<String> getMimeTypes() {
    091        return Collections.unmodifiableList(Arrays.asList("application/x-jexl",
    092                                                          "application/x-jexl2",
    093                                                          "application/x-jexl3"));
    094    }
    095
    096    @Override
    097    public List<String> getNames() {
    098        return Collections.unmodifiableList(Arrays.asList("JEXL", "Jexl", "jexl",
    099                                                          "JEXL2", "Jexl2", "jexl2",
    100                                                          "JEXL3", "Jexl3", "jexl3"));
    101    }
    102
    103    @Override
    104    public String getOutputStatement(final String toDisplay) {
    105        if (toDisplay == null) {
    106            return "JEXL.out.print(null)";
    107        }
    108        return "JEXL.out.print("+StringParser.escapeString(toDisplay, '\'')+")";
    109    }
    110
    111    @Override
    112    public Object getParameter(final String key) {
    113        switch (key) {
    114            case ScriptEngine.ENGINE:
    115                return getEngineName();
    116            case ScriptEngine.ENGINE_VERSION:
    117                return getEngineVersion();
    118            case ScriptEngine.NAME:
    119                return getNames();
    120            case ScriptEngine.LANGUAGE:
    121                return getLanguageName();
    122            case ScriptEngine.LANGUAGE_VERSION:
    123                return getLanguageVersion();
    124            case "THREADING":
    125                /*
    126                 * To implement multithreading, the scripting engine context (inherited from AbstractScriptEngine)
    127                 * would need to be made thread-safe; so would the setContext/getContext methods.
    128                 * It is easier to share the underlying Uberspect and JEXL engine instance, especially
    129                 * with an expression cache.
    130                 */
    131            default:
    132                return null;
    133        }
    134    }
    135
    136    @Override
    137    public String getProgram(final String... statements) {
    138        final StringBuilder sb = new StringBuilder();
    139        for(final String statement : statements){
    140            sb.append(statement.trim());
    141            if (!statement.endsWith(";")){
    142                sb.append(';');
    143            }
    144        }
    145        return sb.toString();
    146    }
    147
    148    @Override
    149    public ScriptEngine getScriptEngine() {
    150        return new JexlScriptEngine(this);
    151    }
    152
    153}