/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you 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
    *
   *   https://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.apache.bcel.util;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.HashMap;
  import java.util.Map;
  
  import org.apache.bcel.classfile.ClassParser;
  import org.apache.bcel.classfile.JavaClass;
  import org.apache.bcel.classfile.Utility;
  
  /**
   * The repository maintains information about which classes have been loaded.
   *
   * It loads its data from the ClassLoader implementation passed into its constructor.
   *
   * @see org.apache.bcel.Repository
   */
  public class ClassLoaderRepository implements Repository {
  
      private final java.lang.ClassLoader loader;
      private final Map<String, JavaClass> loadedClasses = new HashMap<>(); // CLASSNAME X JAVACLASS
  
      /**
       * Constructs a ClassLoaderRepository.
       *
       * @param loader the class loader.
       */
      public ClassLoaderRepository(final java.lang.ClassLoader loader) {
          this.loader = loader;
      }
  
      /**
       * Clear all entries from cache.
       */
      @Override
      public void clear() {
          loadedClasses.clear();
      }
  
      /**
       * Find an already defined JavaClass.
       */
      @Override
      public JavaClass findClass(final String className) {
          return loadedClasses.get(className);
      }
  
      /*
       * @return null.
       */
      @Override
      public ClassPath getClassPath() {
          return null;
      }
  
      @Override
      public JavaClass loadClass(final Class<?> clazz) throws ClassNotFoundException {
          return loadClass(clazz.getName());
      }
  
      /**
       * Lookup a JavaClass object from the Class Name provided.
       */
      @Override
      public JavaClass loadClass(final String className) throws ClassNotFoundException {
          final String classFile = Utility.packageToPath(className);
          JavaClass RC = findClass(className);
          if (RC != null) {
              return RC;
          }
          try (InputStream is = loader.getResourceAsStream(classFile + JavaClass.EXTENSION)) {
              if (is == null) {
                  throw new ClassNotFoundException(className + " not found.");
              }
              final ClassParser parser = new ClassParser(is, className);
              RC = parser.parse();
              storeClass(RC);
              return RC;
          } catch (final IOException e) {
              throw new ClassNotFoundException(className + " not found: " + e, e);
         }
     }
 
     /**
      * Remove class from repository
      */
     @Override
     public void removeClass(final JavaClass clazz) {
         loadedClasses.remove(clazz.getClassName());
     }
 
     /**
      * Store a new JavaClass into this Repository.
      */
     @Override
     public void storeClass(final JavaClass clazz) {
         loadedClasses.put(clazz.getClassName(), clazz);
         clazz.setRepository(this);
     }
 }