src/java.base/share/classes/jdk/internal/loader/ArchivedClassLoaders.java

/*
 * Copyright (c) 2020, 2021, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package jdk.internal.loader;

import java.util.Map;
import jdk.internal.misc.CDS;
import jdk.internal.module.ServicesCatalog;

/**
 * Used to archive the built-in class loaders, their services catalogs, and the
 * package-to-module map used by the built-in class loaders.
 */
class ArchivedClassLoaders {
    private static ArchivedClassLoaders archivedClassLoaders;

    private final ClassLoader bootLoader;
    private final ClassLoader platformLoader;
    private final ClassLoader appLoader;
    private final ServicesCatalog[] servicesCatalogs;
    private final Map<String, ?> packageToModule;

    private ArchivedClassLoaders() {
        bootLoader = ClassLoaders.bootLoader();
        platformLoader = ClassLoaders.platformClassLoader();
        appLoader = ClassLoaders.appClassLoader();

        servicesCatalogs = new ServicesCatalog[3];
        servicesCatalogs[0] = ServicesCatalog.getServicesCatalog(bootLoader);
        servicesCatalogs[1] = ServicesCatalog.getServicesCatalog(platformLoader);
        servicesCatalogs[2] = ServicesCatalog.getServicesCatalog(appLoader);

        packageToModule = BuiltinClassLoader.packageToModule();
    }

    ClassLoader bootLoader() {
        return bootLoader;
    }

    ClassLoader platformLoader() {
        return platformLoader;
    }

    ClassLoader appLoader() {
        return appLoader;
    }

    ServicesCatalog servicesCatalog(ClassLoader loader) {
        if (loader == bootLoader) {
            return servicesCatalogs[0];
        } else if (loader == platformLoader) {
            return servicesCatalogs[1];
        } else if (loader == appLoader) {
            return servicesCatalogs[2];
        } else {
            throw new InternalError();
        }
    }

    Map<String, ?> packageToModule() {
        return packageToModule;
    }

    static void archive() {
        archivedClassLoaders = new ArchivedClassLoaders();
    }

    static ArchivedClassLoaders get() {
        return archivedClassLoaders;
    }

    static {
        CDS.initializeFromArchive(ArchivedClassLoaders.class);
    }
}