com.galeoconsulting.leonardinius.api.impl.ScriptServiceImpl.java Source code

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Here is the source code for com.galeoconsulting.leonardinius.api.impl.ScriptServiceImpl.java

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/*
 * Copyright 2011 Leonid Maslov<leonidms@gmail.com>
 *
 * 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 com.galeoconsulting.leonardinius.api.impl;

import com.galeoconsulting.leonardinius.api.ScriptService;
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.MapMaker;
import org.apache.commons.lang.StringUtils;
import org.springframework.beans.factory.DisposableBean;

import javax.script.ScriptEngine;
import javax.script.ScriptEngineFactory;
import javax.script.ScriptEngineManager;
import java.util.concurrent.ConcurrentMap;

import static com.google.common.base.Preconditions.checkNotNull;

/**
 * User: leonidmaslov
 * Date: 3/12/11
 * Time: 11:19 PM
 */
public class ScriptServiceImpl implements ScriptService, DisposableBean {
    // ------------------------------ FIELDS ------------------------------

    private static final Object DUMMY = new Object();

    private ScriptEngineManager scriptEngineManager;

    private final ConcurrentMap<ScriptEngineFactory, Object> registeredEngines = new MapMaker().weakKeys()
            .makeMap();

    // --------------------------- CONSTRUCTORS ---------------------------

    public ScriptServiceImpl() {
        init();
    }

    private synchronized void init() {
        this.scriptEngineManager = new ScriptEngineManager();
        registeredEngines.clear();
    }

    // ------------------------ INTERFACE METHODS ------------------------

    // --------------------- Interface DisposableBean ---------------------

    @Override
    public void destroy() throws Exception {
        init();
    }

    // --------------------- Interface ScriptService ---------------------

    @Override
    public void defaultRegistration(ScriptEngineFactory engineFactory) {
        for (String extension : engineFactory.getExtensions()) {
            registerEngineExtension(extension, engineFactory);
        }

        for (String mime : engineFactory.getMimeTypes()) {
            registerEngineMime(mime, engineFactory);
        }

        registerEngineLanguage(engineFactory.getLanguageName(), engineFactory);
        registerEngineLanguage((String) engineFactory.getParameter(ScriptEngine.NAME), engineFactory);

        // do not rely on the other methods
        registeredEngines.put(engineFactory, DUMMY);
    }

    @Override
    public ClassLoader getClassLoader(ClassLoader... chainingClassLoaders) {
        return new ChainingClassLoader(chainingClassLoaders);
    }

    @Override
    public ScriptEngine getEngineByExtension(String extension) {
        Preconditions.checkArgument(StringUtils.isNotBlank(extension), "Script extension should be specified!");
        return scriptEngineManager.getEngineByExtension(extension);
    }

    @Override
    public ScriptEngine getEngineByLanguage(String language) {
        Preconditions.checkArgument(StringUtils.isNotBlank(language),
                "Scripting language short name should be specified!");
        return scriptEngineManager.getEngineByName(language);
    }

    @Override
    public ScriptEngine getEngineByMime(String mime) {
        Preconditions.checkArgument(StringUtils.isNotBlank(mime), "Script mime should be specified!");
        return scriptEngineManager.getEngineByMimeType(mime);
    }

    @Override
    public Iterable<ScriptEngineFactory> getRegisteredScriptEngines() {
        return ImmutableList.copyOf(registeredEngines.keySet());
    }

    @Override
    public void registerEngineExtension(String extension, ScriptEngineFactory factory) {
        scriptEngineManager.registerEngineExtension(checkNotNull(extension, "extension"),
                checkNotNull(factory, "factory"));
        registeredEngines.put(factory, DUMMY);
    }

    @Override
    public void registerEngineLanguage(String language, ScriptEngineFactory factory) {
        scriptEngineManager.registerEngineName(checkNotNull(language, "language"),
                checkNotNull(factory, "factory"));
        registeredEngines.put(factory, DUMMY);
    }

    @Override
    public void registerEngineMime(String extension, ScriptEngineFactory factory) {
        scriptEngineManager.registerEngineMimeType(checkNotNull(extension, "extension"),
                checkNotNull(factory, "factory"));
        registeredEngines.put(factory, DUMMY);
    }

    @Override
    public boolean removeEngine(ScriptEngineFactory factory) {
        return registeredEngines.remove(factory, DUMMY);
    }
}