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 *
017 */
018package org.apache.bcel.util;
019
020import java.io.IOException;
021import java.io.InputStream;
022import java.util.HashMap;
023import java.util.Map;
024
025import org.apache.bcel.classfile.ClassParser;
026import org.apache.bcel.classfile.JavaClass;
027
028/**
029 * The repository maintains information about which classes have been loaded.
030 *
031 * It loads its data from the ClassLoader implementation passed into its constructor.
032 *
033 * @see org.apache.bcel.Repository
034 *
035 */
036public class ClassLoaderRepository implements Repository {
037
038    private final java.lang.ClassLoader loader;
039    private final Map<String, JavaClass> loadedClasses = new HashMap<>(); // CLASSNAME X JAVACLASS
040
041    public ClassLoaderRepository(final java.lang.ClassLoader loader) {
042        this.loader = loader;
043    }
044
045    /**
046     * Clear all entries from cache.
047     */
048    @Override
049    public void clear() {
050        loadedClasses.clear();
051    }
052
053    /**
054     * Find an already defined JavaClass.
055     */
056    @Override
057    public JavaClass findClass(final String className) {
058        return loadedClasses.get(className);
059    }
060
061    /*
062     * @return null
063     */
064    @Override
065    public ClassPath getClassPath() {
066        return null;
067    }
068
069    @Override
070    public JavaClass loadClass(final Class<?> clazz) throws ClassNotFoundException {
071        return loadClass(clazz.getName());
072    }
073
074    /**
075     * Lookup a JavaClass object from the Class Name provided.
076     */
077    @Override
078    public JavaClass loadClass(final String className) throws ClassNotFoundException {
079        final String classFile = className.replace('.', '/');
080        JavaClass RC = findClass(className);
081        if (RC != null) {
082            return RC;
083        }
084        try (InputStream is = loader.getResourceAsStream(classFile + ".class")) {
085            if (is == null) {
086                throw new ClassNotFoundException(className + " not found.");
087            }
088            final ClassParser parser = new ClassParser(is, className);
089            RC = parser.parse();
090            storeClass(RC);
091            return RC;
092        } catch (final IOException e) {
093            throw new ClassNotFoundException(className + " not found: " + e, e);
094        }
095    }
096
097    /**
098     * Remove class from repository
099     */
100    @Override
101    public void removeClass(final JavaClass clazz) {
102        loadedClasses.remove(clazz.getClassName());
103    }
104
105    /**
106     * Store a new JavaClass into this Repository.
107     */
108    @Override
109    public void storeClass(final JavaClass clazz) {
110        loadedClasses.put(clazz.getClassName(), clazz);
111        clazz.setRepository(this);
112    }
113}