com.hazelcast.shaded.nonapi.io.github.classgraph.classloaderhandler.ClassGraphClassLoaderHandler Maven / Gradle / Ivy

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/*
 * This file is part of ClassGraph.
 *
 * Author: Luke Hutchison
 *
 * Hosted at: https://github.com/classgraph/classgraph
 *
 * --
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2019 Luke Hutchison
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated
 * documentation files (the "Software"), to deal in the Software without restriction, including without
 * limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 * the Software, and to permit persons to whom the Software is furnished to do so, subject to the following
 * conditions:
 *
 * The above copyright notice and this permission notice shall be included in all copies or substantial
 * portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT
 * LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO
 * EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE
 * OR OTHER DEALINGS IN THE SOFTWARE.
 */
package nonapi.com.hazelcast.shaded.io.github.classgraph.classloaderhandler;

import java.net.URL;

import com.hazelcast.shaded.io.github.classgraph.ClassGraphClassLoader;
import nonapi.com.hazelcast.shaded.io.github.classgraph.classpath.ClassLoaderOrder;
import nonapi.com.hazelcast.shaded.io.github.classgraph.classpath.ClasspathOrder;
import nonapi.com.hazelcast.shaded.io.github.classgraph.scanspec.ScanSpec;
import nonapi.com.hazelcast.shaded.io.github.classgraph.utils.LogNode;

/**
 * Allow for overrideClassLoaders to be called with a ClassGraphClassLoader as a parameter, so that nested scans can
 * share a single classloader (#485).
 */
class ClassGraphClassLoaderHandler implements ClassLoaderHandler {
    /** Class cannot be constructed. */
    private ClassGraphClassLoaderHandler() {
    }

    /**
     * Check whether this {@link ClassLoaderHandler} can handle a given {@link ClassLoader}.
     *
     * @param classLoaderClass
     *            the {@link ClassLoader} class or one of its superclasses.
     * @param log
     *            the log
     * @return true if this {@link ClassLoaderHandler} can handle the {@link ClassLoader}.
     */
    public static boolean canHandle(final Class classLoaderClass, final LogNode log) {
        final boolean matches = "com.hazelcast.shaded.io.github.classgraph.ClassGraphClassLoader".equals(classLoaderClass.getName());
        if (matches && log != null) {
            log.log("Sharing a `ClassGraphClassLoader` between multiple nested scans is not advisable, "
                    + "because scan criteria may differ between scans. "
                    + "See: https://github.com/classgraph/classgraph/issues/485");
        }
        return matches;
    }

    /**
     * Find the {@link ClassLoader} delegation order for a {@link ClassLoader}.
     *
     * @param classLoader
     *            the {@link ClassLoader} to find the order for.
     * @param classLoaderOrder
     *            a {@link ClassLoaderOrder} object to update.
     * @param log
     *            the log
     */
    public static void findClassLoaderOrder(final ClassLoader classLoader, final ClassLoaderOrder classLoaderOrder,
            final LogNode log) {
        classLoaderOrder.delegateTo(classLoader.getParent(), /* isParent = */ true, log);
        classLoaderOrder.add(classLoader, log);
    }

    /**
     * Find the classpath entries for the associated {@link ClassLoader}.
     *
     * @param classLoader
     *            the {@link ClassLoader} to find the classpath entries order for.
     * @param classpathOrder
     *            a {@link ClasspathOrder} object to update.
     * @param scanSpec
     *            the {@link ScanSpec}.
     * @param log
     *            the log.
     */
    public static void findClasspathOrder(final ClassLoader classLoader, final ClasspathOrder classpathOrder,
            final ScanSpec scanSpec, final LogNode log) {
        // ClassGraphClassLoader overrides URLClassLoader, so we can get the basic classpath URLs the same
        // way as for URLClassLoader. However, classloading will try to preferentially reuse the older
        // ClassGraphClassLoader before loading with the new ClassGraphClassLoader from the current scan,
        // so the following URLs will be scanned by the current scan, but classes will only be loaded from
        // these URLs if the older classloader fails.
        for (final URL url : ((ClassGraphClassLoader) classLoader).getURLs()) {
            if (url != null) {
                classpathOrder.addClasspathEntry(url, classLoader, scanSpec, log);
            }
        }
    }
}