MemorySensitiveClassPathRepository.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.bcel.util;

import java.lang.ref.SoftReference;
import java.util.HashMap;
import java.util.Map;

import org.apache.bcel.classfile.JavaClass;

/**
 * This repository is used in situations where a Class is created outside the realm of a ClassLoader. Classes are loaded
 * from the file systems using the paths specified in the given class path. By default, this is the value returned by
 * ClassPath.getClassPath(). This repository holds onto classes with SoftReferences, and will reload as needed, in cases
 * where memory sizes are important.
 *
 * @see org.apache.bcel.Repository
 */
public class MemorySensitiveClassPathRepository extends AbstractClassPathRepository {

    private final Map<String, SoftReference<JavaClass>> loadedClasses = new HashMap<>(); // CLASSNAME X JAVACLASS

    public MemorySensitiveClassPathRepository(final ClassPath path) {
        super(path);
    }

    /**
     * Clear all entries from cache.
     */
    @Override
    public void clear() {
        loadedClasses.clear();
    }

    /**
     * Find an already defined (cached) JavaClass object by name.
     */
    @Override
    public JavaClass findClass(final String className) {
        final SoftReference<JavaClass> ref = loadedClasses.get(className);
        return ref == null ? null : ref.get();
    }

    /**
     * Remove class from repository
     */
    @Override
    public void removeClass(final JavaClass clazz) {
        loadedClasses.remove(clazz.getClassName());
    }

    /**
     * Store a new JavaClass instance into this Repository.
     */
    @Override
    public void storeClass(final JavaClass clazz) {
        // Not calling super.storeClass because this subclass maintains the mapping.
        loadedClasses.put(clazz.getClassName(), new SoftReference<>(clazz));
        clazz.setRepository(this);
    }
}