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.lang.ref.SoftReference;
021import java.util.HashMap;
022import java.util.Map;
023
024import org.apache.bcel.classfile.JavaClass;
025
026/**
027 * This repository is used in situations where a Class is created outside the realm of a ClassLoader. Classes are loaded
028 * from the file systems using the paths specified in the given class path. By default, this is the value returned by
029 * ClassPath.getClassPath(). This repository holds onto classes with SoftReferences, and will reload as needed, in cases
030 * where memory sizes are important.
031 *
032 * @see org.apache.bcel.Repository
033 */
034public class MemorySensitiveClassPathRepository extends AbstractClassPathRepository {
035
036    private final Map<String, SoftReference<JavaClass>> loadedClasses = new HashMap<>(); // CLASSNAME X JAVACLASS
037
038    public MemorySensitiveClassPathRepository(final ClassPath path) {
039        super(path);
040    }
041
042    /**
043     * Clear all entries from cache.
044     */
045    @Override
046    public void clear() {
047        loadedClasses.clear();
048    }
049
050    /**
051     * Find an already defined (cached) JavaClass object by name.
052     */
053    @Override
054    public JavaClass findClass(final String className) {
055        final SoftReference<JavaClass> ref = loadedClasses.get(className);
056        if (ref == null) {
057            return null;
058        }
059        return ref.get();
060    }
061
062    /**
063     * Remove class from repository
064     */
065    @Override
066    public void removeClass(final JavaClass clazz) {
067        loadedClasses.remove(clazz.getClassName());
068    }
069
070    /**
071     * Store a new JavaClass instance into this Repository.
072     */
073    @Override
074    public void storeClass(final JavaClass clazz) {
075        // Not calling super.storeClass because this subclass maintains the mapping.
076        loadedClasses.put(clazz.getClassName(), new SoftReference<>(clazz));
077        clazz.setRepository(this);
078    }
079}