Groovy example source code file (GroovyScriptEngineFactory.java)

This example Groovy source code file (GroovyScriptEngineFactory.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Groovy tags/keywords

arraylist, extensions, groovy, language_name, list, list, mime_types, mime_types, names, string, string, stringbuilder, stringbuilder, util, version

The Groovy GroovyScriptEngineFactory.java source code

/*
 * Copyright 2003-2010 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.codehaus.groovy.jsr223;

import groovy.lang.GroovySystem;

import javax.script.ScriptEngine;
import javax.script.ScriptEngineFactory;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

/**
 * A factory class conforming to JSR-223 which is used to instantiate
 * Groovy <code>ScriptEngines and also exposes metadata describing
 * Groovy's engine class.
 *
 * @author Adapted from original by Mike Grogan
 * @author Adapted from original by A. Sundararajan
 * @author Jim White
 * @author Guillaume Laforge
 */
public class GroovyScriptEngineFactory implements ScriptEngineFactory {

    private static final String VERSION = "2.0";

    private static final String SHORT_NAME = "groovy";

    private static final String LANGUAGE_NAME = "Groovy";

    public String getEngineName() {
        return "Groovy Scripting Engine";
    }

    /**
     * Note that the scripting.dev.java.net engine had this backwards.
     * The engine version refers to this engine implementation.
     * Whereas language version refers to the groovy implementation
     * (which is obtained from the runtime).
     */
    public String getEngineVersion() {
        return VERSION;
    }

    /**
     * This is also different than scripting.dev.java.net which used an
     * initial lowercase.  But these are proper names and should be capitalized.
     */
    public String getLanguageName() {
        return LANGUAGE_NAME;
    }

    public String getLanguageVersion() {
        return GroovySystem.getVersion();
    }

    public List<String> getExtensions() {
        return EXTENSIONS;
    }

    public List<String> getMimeTypes() {
        return MIME_TYPES;
    }

    public List<String> getNames() {
        return NAMES;
    }

    public Object getParameter(String key) {

        if (ScriptEngine.NAME.equals(key)) {
            return SHORT_NAME;
        } else if (ScriptEngine.ENGINE.equals(key)) {
            return getEngineName();
        } else if (ScriptEngine.ENGINE_VERSION.equals(key)) {
            return VERSION;
        } else if (ScriptEngine.LANGUAGE.equals(key)) {
            return LANGUAGE_NAME;
        } else if (ScriptEngine.LANGUAGE_VERSION.equals(key)) {
            return GroovySystem.getVersion();
        } else if ("THREADING".equals(key)) {
            return "MULTITHREADED";
        } else {
            throw new IllegalArgumentException("Invalid key");
        }

    }

    public ScriptEngine getScriptEngine() {
        return new GroovyScriptEngineImpl();
    }

    public String getMethodCallSyntax(String obj, String method,
                                      String... args) {

        String ret = obj + "." + method + "(";
        int len = args.length;
        if (len == 0) {
            ret += ")";
            return ret;
        }

        for (int i = 0; i < len; i++) {
            ret += args[i];
            if (i != len - 1) {
                ret += ",";
            } else {
                ret += ")";
            }
        }
        return ret;
    }

    public String getOutputStatement(String toDisplay) {
        StringBuilder buf = new StringBuilder();
        buf.append("println(\"");
        int len = toDisplay.length();
        for (int i = 0; i < len; i++) {
            char ch = toDisplay.charAt(i);
            switch (ch) {
                case '"':
                    buf.append("\\\"");
                    break;
                case '\\':
                    buf.append("\\\\");
                    break;
                default:
                    buf.append(ch);
                    break;
            }
        }
        buf.append("\")");
        return buf.toString();
    }

    public String getProgram(String... statements) {
        StringBuilder ret = new StringBuilder();
        int len = statements.length;
        for (int i = 0; i < len; i++) {
            ret.append(statements[i]);
            ret.append('\n');
        }
        return ret.toString();
    }

    private static final List<String> NAMES;
    private static final List<String> EXTENSIONS;
    private static final List<String> MIME_TYPES;

    static {
        List<String> n = new ArrayList(2);
        n.add(SHORT_NAME);
        n.add(LANGUAGE_NAME);
        NAMES = Collections.unmodifiableList(n);

        n = new ArrayList<String>(1);
        n.add("groovy");
        EXTENSIONS = Collections.unmodifiableList(n);

        n = new ArrayList<String>(1);
        n.add("application/x-groovy");
        MIME_TYPES = Collections.unmodifiableList(n);
    }
}