**** BEGIN LICENSE BLOCK *****
Version: EPL 2.0/GPL 2.0/LGPL 2.1
The contents of this file are subject to the Eclipse Public
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.eclipse.org/legal/epl-v20.html
Software distributed under the License is distributed on an "AS
IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
implied. See the License for the specific language governing
rights and limitations under the License.
Copyright (C) 2009 Yoko Harada 
Alternatively, the contents of this file may be used under the terms of
either of the GNU General Public License Version 2 or later (the "GPL"),
or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
in which case the provisions of the GPL or the LGPL are applicable instead
of those above. If you wish to allow use of your version of this file only
under the terms of either the GPL or the LGPL, and not to allow others to
use your version of this file under the terms of the EPL, indicate your
decision by deleting the provisions above and replace them with the notice
and other provisions required by the GPL or the LGPL. If you do not delete
the provisions above, a recipient may use your version of this file under
the terms of any one of the EPL, the GPL or the LGPL.
 **** END LICENSE BLOCK *****
/**
 * **** BEGIN LICENSE BLOCK *****
 * Version: EPL 2.0/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Eclipse Public
 * 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.eclipse.org/legal/epl-v20.html
 *
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * Copyright (C) 2009 Yoko Harada <yokolet@gmail.com>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the EPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the EPL, the GPL or the LGPL.
 * **** END LICENSE BLOCK *****
 */
package org.jruby.embed.jsr223;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.script.Bindings;
import javax.script.ScriptContext;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineFactory;
import javax.script.ScriptException;
import javax.script.SimpleBindings;

This is a substitute of javax.script.ScriptEngineManager.
With this script engine manager, you can avoid two known troubles. One this
happens on OS X JDK 5 which tries to load AppleScriptEngine and ends up in the
exception. Another one happens when you use livetribe version of javax.script
and GLOBAL_SCOPE. The livetribe javax.script has a bug to handle GLOBAL_SCOPE.
Author:
Yoko Harada /**
 * This is a substitute of javax.script.ScriptEngineManager.
 *
 * With this script engine manager, you can avoid two known troubles. One this
 * happens on OS X JDK 5 which tries to load AppleScriptEngine and ends up in the
 * exception. Another one happens when you use livetribe version of javax.script
 * and GLOBAL_SCOPE. The livetribe javax.script has a bug to handle GLOBAL_SCOPE.
 *
 * @author Yoko Harada <yokolet@gmail.com>
 */
public class JRubyScriptEngineManager {

    static final String SERVICE = "META-INF/services/javax.script.ScriptEngineFactory";

    private final Collection<ScriptEngineFactory> factories;
    private final Map<String, ScriptEngineFactory> nameMap;
    private final Map<String, ScriptEngineFactory> extensionMap;
    private final Map<String, ScriptEngineFactory> mimetypeMap;
    private Bindings globalMap;

    public JRubyScriptEngineManager() throws ScriptException {
        this(null);
    }

    public JRubyScriptEngineManager(ClassLoader loader) throws ScriptException {
        nameMap = new HashMap<String, ScriptEngineFactory>();
        extensionMap = new HashMap<String, ScriptEngineFactory>();
        mimetypeMap = new HashMap<String, ScriptEngineFactory>();
        globalMap = new SimpleBindings();
        try {
            factories = new ServiceFinder<ScriptEngineFactory>(SERVICE, loader).getServices();
            if ( factories.isEmpty() ) {
                System.err.println("no factory"); // TODO this is fatal, right?
            }
            prepareMaps();
        }
        catch (Exception e) {
            e.printStackTrace();
            throw new ScriptException(e);
        }
    }

    private void prepareMaps() {
        for (ScriptEngineFactory factory : factories) {
            List<String> names = factory.getNames();
            for (String name : names) {
                nameMap.put(name, factory);
            }
            List<String> extensions = factory.getExtensions();
            for (String extension : extensions) {
                extensionMap.put(extension, factory);
            }
            List<String> mimeTypes = factory.getMimeTypes();
            for (String mimeType : mimeTypes) {
                mimetypeMap.put(mimeType, factory);
            }
        }
    }

    public void setBindings(final Bindings bindings) {
        if (bindings == null) {
            throw new IllegalArgumentException("Null bindings");
        }
        globalMap = bindings;
    }

    public Bindings getBindings() {
        return globalMap;
    }

    public void put(String key, Object value) {
        globalMap.put(key, value);
    }

    public Object get(String key) {
        return globalMap.get(key);
    }

    public ScriptEngine getEngineByName(String shortName) {
        if (shortName == null) {
            throw new NullPointerException("Null symbolicName");
        }
        ScriptEngineFactory factory = nameMap.get(shortName);
        if (factory == null) {
            throw new IllegalArgumentException("No engine for " + shortName);
        }
        ScriptEngine engine = factory.getScriptEngine();
        engine.getContext().setBindings(globalMap, ScriptContext.GLOBAL_SCOPE);
        return engine;
    }

    public ScriptEngine getEngineByExtension(String extension) {
        if (extension == null) {
            throw new NullPointerException("Null extension");
        }
        ScriptEngineFactory factory = extensionMap.get(extension);
        if (factory == null) {
            throw new IllegalArgumentException("No engine for " + extension);
        }
        ScriptEngine engine = factory.getScriptEngine();
        engine.getContext().setBindings(globalMap, ScriptContext.GLOBAL_SCOPE);
        return engine;
    }

    public ScriptEngine getEngineByMimeType(String mimeType) {
        if (mimeType == null) {
            throw new NullPointerException("Null mimeType");
        }
        ScriptEngineFactory factory = mimetypeMap.get(mimeType);
        if (factory == null) {
            throw new IllegalArgumentException("No engine for " + mimeType);
        }
        ScriptEngine engine = factory.getScriptEngine();
        engine.getContext().setBindings(globalMap, ScriptContext.GLOBAL_SCOPE);
        return engine;
    }

    public List<ScriptEngineFactory> getEngineFactories() {
        return Collections.unmodifiableList(new ArrayList<ScriptEngineFactory>(factories));
    }

    public void registerEngineName(String name, ScriptEngineFactory factory) {
        if (name == null || factory == null) {
            throw new NullPointerException("name and/or factory is null.");
        }
        nameMap.put(name, factory);
    }

    public void registerEngineMimeType(String type, ScriptEngineFactory factory) {
        if (type == null || factory == null) {
            throw new NullPointerException("type and/or factory is null.");
        }
        mimetypeMap.put(type, factory);
    }

    public void registerEngineExtension(String extension, ScriptEngineFactory factory) {
        if (extension == null || factory == null) {
            throw new NullPointerException("extension and/or factory is null.");
        }
        extensionMap.put(extension, factory);
    }
}