/**

  * Back 2 Browser Bytecode Translator

  * Copyright (C) 2012 Jaroslav Tulach <jaroslav.tulach@apidesign.org>

  *

  * This program is free software: you can redistribute it and/or modify

  * it under the terms of the GNU General Public License as published by

  * the Free Software Foundation, version 2 of the License.

  *

  * This program is distributed in the hope that it will be useful,

  * but WITHOUT ANY WARRANTY; without even the implied warranty of

  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

  * GNU General Public License for more details.

  *

  * You should have received a copy of the GNU General Public License

  * along with this program. Look for COPYING file in the top folder.

  * If not, see http://opensource.org/licenses/GPL-2.0.

  */

 package org.apidesign.vm4brwsr;

 import java.io.IOException;

 import java.io.InputStream;

 import java.util.HashMap;

 import java.util.Map;

 import org.apidesign.bck2brwsr.core.ExtraJavaScript;

 import org.apidesign.vm4brwsr.ByteCodeParser.ClassData;

 @ExtraJavaScript(processByteCode = false, resource="")

 final class ClassDataCache {

     private static final Object MISSING_CLASS = new Object();

     private final Bck2Brwsr.Resources resources;

     private final Map<String, Object> classDataMap;

     ClassDataCache(final Bck2Brwsr.Resources resources) {

         this.resources = resources;

         classDataMap = new HashMap<String, Object>();

     }

     ClassData getClassData(final String className) throws IOException {

         Object cacheEntry = classDataMap.get(className);

         if (cacheEntry == null) {

             final InputStream is = loadClass(resources, className);

             cacheEntry = (is != null) ? new ClassData(is) : MISSING_CLASS;

             classDataMap.put(className, cacheEntry);

         }

         return (cacheEntry != MISSING_CLASS) ? (ClassData) cacheEntry : null;

     }

     private static InputStream loadClass(Bck2Brwsr.Resources l, String name)

             throws IOException {

         return l.get(name + ".class"); // NOI18N

     }

 }