001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 *  Unless required by applicable law or agreed to in writing, software
012 *  distributed under the License is distributed on an "AS IS" BASIS,
013 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 *  See the License for the specific language governing permissions and
015 *  limitations under the License.
016 */
017package org.apache.bcel.util;
018
019import java.io.IOException;
020import java.io.InputStream;
021import java.util.HashMap;
022import java.util.Map;
023
024import org.apache.bcel.classfile.ClassParser;
025import org.apache.bcel.classfile.JavaClass;
026
027/**
028 * The repository maintains information about which classes have been loaded.
029 *
030 * It loads its data from the ClassLoader implementation passed into its constructor.
031 *
032 * @see org.apache.bcel.Repository
033 */
034public class ClassLoaderRepository implements Repository {
035
036    private final java.lang.ClassLoader loader;
037    private final Map<String, JavaClass> loadedClasses = new HashMap<>(); // CLASSNAME X JAVACLASS
038
039    public ClassLoaderRepository(final java.lang.ClassLoader loader) {
040        this.loader = loader;
041    }
042
043    /**
044     * Clear all entries from cache.
045     */
046    @Override
047    public void clear() {
048        loadedClasses.clear();
049    }
050
051    /**
052     * Find an already defined JavaClass.
053     */
054    @Override
055    public JavaClass findClass(final String className) {
056        return loadedClasses.get(className);
057    }
058
059    /*
060     * @return null
061     */
062    @Override
063    public ClassPath getClassPath() {
064        return null;
065    }
066
067    @Override
068    public JavaClass loadClass(final Class<?> clazz) throws ClassNotFoundException {
069        return loadClass(clazz.getName());
070    }
071
072    /**
073     * Lookup a JavaClass object from the Class Name provided.
074     */
075    @Override
076    public JavaClass loadClass(final String className) throws ClassNotFoundException {
077        final String classFile = className.replace('.', '/');
078        JavaClass RC = findClass(className);
079        if (RC != null) {
080            return RC;
081        }
082        try (InputStream is = loader.getResourceAsStream(classFile + ".class")) {
083            if (is == null) {
084                throw new ClassNotFoundException(className + " not found.");
085            }
086            final ClassParser parser = new ClassParser(is, className);
087            RC = parser.parse();
088            storeClass(RC);
089            return RC;
090        } catch (final IOException e) {
091            throw new ClassNotFoundException(className + " not found: " + e, e);
092        }
093    }
094
095    /**
096     * Remove class from repository
097     */
098    @Override
099    public void removeClass(final JavaClass clazz) {
100        loadedClasses.remove(clazz.getClassName());
101    }
102
103    /**
104     * Store a new JavaClass into this Repository.
105     */
106    @Override
107    public void storeClass(final JavaClass clazz) {
108        loadedClasses.put(clazz.getClassName(), clazz);
109        clazz.setRepository(this);
110    }
111}