//
// ========================================================================
// Copyright (c) 1995-2020 Mort Bay Consulting Pty Ltd and others.
//
// This program and the accompanying materials are made available under
// the terms of the Eclipse Public License 2.0 which is available at
// https://www.eclipse.org/legal/epl-2.0
//
// This Source Code may also be made available under the following
// Secondary Licenses when the conditions for such availability set
// forth in the Eclipse Public License, v. 2.0 are satisfied:
// the Apache License v2.0 which is available at
// https://www.apache.org/licenses/LICENSE-2.0
//
// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
// ========================================================================
//

package org.eclipse.jetty.util.preventers;

import org.eclipse.jetty.util.component.AbstractLifeCycle;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

AbstractLeakPreventer
Abstract base class for code that seeks to avoid pinning of webapp classloaders by using the jetty classloader to
proactively call the code that pins them (generally pinned as static data members, or as static
data members that are daemon threads (which use the context classloader)).
Instances of subclasses of this class should be set with Server.addBean(), which will
ensure that they are called when the Server instance starts up, which will have the jetty
classloader in scope.
/**
 * AbstractLeakPreventer
 *
 * Abstract base class for code that seeks to avoid pinning of webapp classloaders by using the jetty classloader to
 * proactively call the code that pins them (generally pinned as static data members, or as static
 * data members that are daemon threads (which use the context classloader)).
 *
 * Instances of subclasses of this class should be set with Server.addBean(), which will
 * ensure that they are called when the Server instance starts up, which will have the jetty
 * classloader in scope.
 */
public abstract class AbstractLeakPreventer extends AbstractLifeCycle
{
    protected static final Logger LOG = LoggerFactory.getLogger(AbstractLeakPreventer.class);

    public abstract void prevent(ClassLoader loader);

    @Override
    protected void doStart() throws Exception
    {
        ClassLoader loader = Thread.currentThread().getContextClassLoader();
        try
        {
            Thread.currentThread().setContextClassLoader(getClass().getClassLoader());
            prevent(getClass().getClassLoader());
            super.doStart();
        }
        finally
        {
            Thread.currentThread().setContextClassLoader(loader);
        }
    }
}