    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one
    003 * or more contributor license agreements.  See the NOTICE file
    004 * distributed with this work for additional information
    005 * regarding copyright ownership.  The ASF licenses this file
    006 * to you under the Apache License, Version 2.0 (the
    007 * "License"); you may not use this file except in compliance
    008 * with the License.  You may obtain a copy of the License at
    009 *
    010 *   https://www.apache.org/licenses/LICENSE-2.0
    011 *
    012 * Unless required by applicable law or agreed to in writing,
    013 * software distributed under the License is distributed on an
    014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    015 * KIND, either express or implied.  See the License for the
    016 * specific language governing permissions and limitations
    017 * under the License.
    018 */
    019package org.apache.bcel.util;
    020
    021import java.lang.ref.SoftReference;
    022import java.util.HashMap;
    023import java.util.Map;
    024
    025import org.apache.bcel.classfile.JavaClass;
    026
    027/**
    028 * This repository is used in situations where a Class is created outside the realm of a ClassLoader. Classes are loaded
    029 * from the file systems using the paths specified in the given class path. By default, this is the value returned by
    030 * ClassPath.getClassPath(). This repository holds onto classes with SoftReferences, and will reload as needed, in cases
    031 * where memory sizes are important.
    032 *
    033 * @see org.apache.bcel.Repository
    034 */
    035public class MemorySensitiveClassPathRepository extends AbstractClassPathRepository {
    036
    037    private final Map<String, SoftReference<JavaClass>> loadedClasses = new HashMap<>(); // CLASSNAME X JAVACLASS
    038
    039    public MemorySensitiveClassPathRepository(final ClassPath path) {
    040        super(path);
    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 (cached) JavaClass object by name.
    053     */
    054    @Override
    055    public JavaClass findClass(final String className) {
    056        final SoftReference<JavaClass> ref = loadedClasses.get(className);
    057        return ref == null ? null : ref.get();
    058    }
    059
    060    /**
    061     * Remove class from repository
    062     */
    063    @Override
    064    public void removeClass(final JavaClass clazz) {
    065        loadedClasses.remove(clazz.getClassName());
    066    }
    067
    068    /**
    069     * Store a new JavaClass instance into this Repository.
    070     */
    071    @Override
    072    public void storeClass(final JavaClass clazz) {
    073        // Not calling super.storeClass because this subclass maintains the mapping.
    074        loadedClasses.put(clazz.getClassName(), new SoftReference<>(clazz));
    075        clazz.setRepository(this);
    076    }
    077}