/*
 * Copyright  2000-2004 The Apache Software Foundation
 *
 *  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.apache.bcel.util;


import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;

import org.apache.bcel.classfile.ClassParser;
import org.apache.bcel.classfile.JavaClass;

/**
 * This repository is used in situations where a Class is created
 * outside the realm of a ClassLoader. Classes are loaded from
 * the file systems using the paths specified in the given
 * class path. By default, this is the value returned by
 * ClassPath.getClassPath().
 * <br>
 * It is designed to be used as a singleton, however it
 * can also be used with custom classpaths.
 *
/**
 * Abstract definition of a class repository. Instances may be used
 * to load classes from different sources and may be used in the
 * Repository.setRepository method.
 *
 * @see org.apache.bcel.Repository
 *
 * @version $Id$
 * @author <A HREF="mailto:m.dahm@gmx.de">M. Dahm</A>
 * @author David Dixon-Peugh
 */
public class SyntheticRepository implements Repository {
  private static final String DEFAULT_PATH = ClassPath.getClassPath();

  private static HashMap _instances = new HashMap(); // CLASSPATH X REPOSITORY

  private ClassPath _path = null;
  private HashMap _loadedClasses = new HashMap(); // CLASSNAME X JAVACLASS

  private SyntheticRepository(ClassPath path) {
    _path = path;
  }

  public static SyntheticRepository getInstance() {
    return getInstance(ClassPath.SYSTEM_CLASS_PATH);
  }

  public static SyntheticRepository getInstance(ClassPath classPath) {
    SyntheticRepository rep = (SyntheticRepository)_instances.get(classPath);

    if (rep == null) {
      rep = new SyntheticRepository(classPath);
      _instances.put(classPath, rep);
    }

    return rep;
  }

  /**
   * Store a new JavaClass instance into this Repository.
   */
  public void storeClass(JavaClass clazz) {
    _loadedClasses.put(clazz.getClassName(), clazz);
    clazz.setRepository(this);
  }

  /**
   * Remove class from repository
   */
  public void removeClass(JavaClass clazz) {
    _loadedClasses.remove(clazz.getClassName());
  }

  /**
   * Find an already defined (cached) JavaClass object by name.
   */
  public JavaClass findClass(String className) {
    return (JavaClass)_loadedClasses.get(className);
  }

  /**
   * Find a JavaClass object by name.
   * If it is already in this Repository, the Repository version
   * is returned.  Otherwise, the Repository's classpath is searched for
   * the class (and it is added to the Repository if found).
   *
   * @param className the name of the class
   * @return the JavaClass object
   * @throws ClassNotFoundException if the class is not in the
   *   Repository, and could not be found on the classpath
   */
  public JavaClass loadClass(String className) throws ClassNotFoundException {
    if (className == null || className.equals("")) {
      throw new IllegalArgumentException("Invalid class name " + className);
    }

    className = className.replace('/', '.'); // Just in case, canonical form

    JavaClass clazz = findClass(className);
    if (clazz != null) {
      return clazz;
    }

    try {
      return loadClass(_path.getInputStream(className), className);
    } catch (IOException e) {
      throw new ClassNotFoundException(
        "Exception while looking for class " + className + ": " + e.toString());
    }
  }

  /**
   * Find the JavaClass object for a runtime Class object.
   * If a class with the same name is already in this Repository,
   * the Repository version is returned.  Otherwise, getResourceAsStream()
   * is called on the Class object to find the class's representation.
   * If the representation is found, it is added to the Repository.
   *
   * @see Class
   * @param clazz the runtime Class object
   * @return JavaClass object for given runtime class
   * @throws ClassNotFoundException if the class is not in the
   *   Repository, and its representation could not be found
   */
  public JavaClass loadClass(Class clazz) throws ClassNotFoundException {
    String className = clazz.getName();

    JavaClass repositoryClass = findClass(className);
    if (repositoryClass != null) {
      return repositoryClass;
    }

    String name = className;
    int i = name.lastIndexOf('.');

    if (i > 0) {
      name = name.substring(i + 1);
    }

    return loadClass(clazz.getResourceAsStream(name + ".class"), className);
  }

  private JavaClass loadClass(InputStream is, String className)
    throws ClassNotFoundException {

    try {
      if (is != null) {
        ClassParser parser = new ClassParser(is, className);
        JavaClass clazz = parser.parse();

        storeClass(clazz);

        return clazz;
      }
    } catch (IOException e) {
      throw new ClassNotFoundException(
        "Exception while looking for class " + className + ": " + e.toString());
    }

    throw new ClassNotFoundException(
      "SyntheticRepository could not load " + className);
  }

  /** ClassPath associated with the Repository.
   */
  public ClassPath getClassPath() {
    return _path;
  }

  /** Clear all entries from cache.
   */
  public void clear() {
    _loadedClasses.clear();
  }
}

@@ -716,16 +716,52 @@
 Stream;%0A
+import java.lang.ref.SoftReference;%0A
 import j
@@ -2523,22 +2523,41 @@
 Name(), 
+new SoftReference(
 clazz)
+)
 ;%0A    cl
@@ -2864,54 +2864,144 @@
     
-return (JavaClass)_loadedClasses.get(className
+SoftReference ref = (SoftReference)_loadedClasses.get(className);%0A    if (ref == null)%0A      return null;%0A    return (JavaClass)ref.get(
 );%0A 

Apply Patch 32945 Make the SyntheticRepository a memory sensitive cache.