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Jetty web application support

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//
// ========================================================================
// Copyright (c) 1995 Mort Bay Consulting Pty Ltd and others.
//
// This program and the accompanying materials are made available under the
// terms of the Eclipse Public License v. 2.0 which is available at
// https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
// 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.webapp;

import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

import org.eclipse.jetty.xml.XmlParser;

/**
 * IterativeDescriptorProcessor
 */
public abstract class IterativeDescriptorProcessor implements DescriptorProcessor
{
    public static final Class[] __signature = new Class[]{WebAppContext.class, Descriptor.class, XmlParser.Node.class};
    protected Map _visitors = new HashMap();

    public abstract void start(WebAppContext context, Descriptor descriptor);

    public abstract void end(WebAppContext context, Descriptor descriptor);

    /**
     * Register a method to be called back when visiting the node with the given name.
     * The method must exist on a subclass of this class, and must have the signature:
     * public void method (Descriptor descriptor, XmlParser.Node node)
     *
     * @param nodeName the node name
     * @param m the method name
     */
    public void registerVisitor(String nodeName, Method m)
    {
        _visitors.put(nodeName, m);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void process(WebAppContext context, Descriptor descriptor)
        throws Exception
    {
        if (descriptor == null)
            return;

        start(context, descriptor);

        XmlParser.Node root = descriptor.getRoot();
        Iterator iter = root.iterator();
        XmlParser.Node node = null;
        while (iter.hasNext())
        {
            Object o = iter.next();
            if (!(o instanceof XmlParser.Node))
                continue;
            node = (XmlParser.Node)o;
            visit(context, descriptor, node);
        }

        end(context, descriptor);
    }

    protected void visit(WebAppContext context, Descriptor descriptor, XmlParser.Node node)
        throws Exception
    {
        String name = node.getTag();
        Method m = _visitors.get(name);
        if (m != null)
            m.invoke(this, new Object[]{context, descriptor, node});
    }
}