    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}