import org.openide.util.RequestProcessor;

                Exception e = new Exception();

                final int len = e.getStackTrace().length;

                System.err.println("depth: " + len);

                if (len > 300) {

                    System.err.println("too deep");

                }

import java.lang.reflect.Array;

import java.util.EventListener;

                } finally {

                    uninstallCoaleasingListener(l);

        private CoaleasingListener installCoaleasingListener() {

            synchronized (proxy()) {

                if (listeners == null) {

                    return null;

                }

                if (listeners instanceof CoaleasingListener) {

                    CoaleasingListener ca = (CoaleasingListener)listeners;

                    ca.changeUsage(1);

                    return ca;

                }

                final CoaleasingListener ca = new CoaleasingListener(listeners);

                listeners = ca;

                return ca;

            }

        }

        private void uninstallCoaleasingListener(CoaleasingListener l) {

            if (l == null) {

                return;

            }

            synchronized (proxy()) {

                CoaleasingListener ca = (CoaleasingListener) listeners;

                if (ca.changeUsage(-1)) {

                    listeners = l.delegate;

                }

            }

            l.deliver();

        }

    private static final class CoaleasingListener extends EventListenerList 

    implements LookupListener {

        final EventListenerList delegate;

        private volatile LookupEvent toDeliver;

        private int usageCount;

        public CoaleasingListener(EventListenerList delegate) {

            this.delegate = delegate;

            this.usageCount = 1;

        }

        final boolean changeUsage(int delta) {

            usageCount += delta;

            return usageCount == 0;

        }

        @Override

        public Object[] getListenerList() {

            return new Object[] { LookupListener.class, this };

        }

        @Override

        public <T extends EventListener> T[] getListeners(Class<T> t) {

            int n = LookupListener.class == t ? 1 : 0;

            T[] result = (T[])Array.newInstance(t, n); 

            if (n > 0) {

                result[0] = (T) this;

            }

            return result;

        }

        @Override

        public int getListenerCount() {

            return 1;

        }

        @Override

        public int getListenerCount(Class<?> t) {

            return LookupListener.class == t ? 1 : 0;

        }

        @Override

        public <T extends EventListener> void add(Class<T> t, T l) {

            delegate.add(t, l);

        }

        @Override

        public <T extends EventListener> void remove(Class<T> t, T l) {

            delegate.remove(t, l);

        }

        @Override

        public void resultChanged(LookupEvent ev) {

            if (toDeliver == null) {

                toDeliver = ev;

            }

            assert toDeliver.getSource() == ev.getSource();

        }

        final void deliver() {

            LookupEvent ev = toDeliver;

            if (ev != null) {

                for (LookupListener l : delegate.getListeners(LookupListener.class)) {

                    l.resultChanged(ev);

                }

            }

        }

    }

/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.

 *

 * Copyright 2012 Oracle and/or its affiliates. All rights reserved.

 *

 * Oracle and Java are registered trademarks of Oracle and/or its affiliates.

 * Other names may be trademarks of their respective owners.

 *

 * The contents of this file are subject to the terms of either the GNU

 * General Public License Version 2 only ("GPL") or the Common

 * Development and Distribution License("CDDL") (collectively, the

 * "License"). You may not use this file except in compliance with the

 * License. You can obtain a copy of the License at

 * http://www.netbeans.org/cddl-gplv2.html

 * or nbbuild/licenses/CDDL-GPL-2-CP. See the License for the

 * specific language governing permissions and limitations under the

 * License.  When distributing the software, include this License Header

 * Notice in each file and include the License file at

 * nbbuild/licenses/CDDL-GPL-2-CP.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the GPL Version 2 section of the License file that

 * accompanied this code. If applicable, add the following below the

 * License Header, with the fields enclosed by brackets [] replaced by

 * your own identifying information:

 * "Portions Copyrighted [year] [name of copyright owner]"

 *

 * If you wish your version of this file to be governed by only the CDDL

 * or only the GPL Version 2, indicate your decision by adding

 * "[Contributor] elects to include this software in this distribution

 * under the [CDDL or GPL Version 2] license." If you do not indicate a

 * single choice of license, a recipient has the option to distribute

 * your version of this file under either the CDDL, the GPL Version 2 or

 * to extend the choice of license to its licensees as provided above.

 * However, if you add GPL Version 2 code and therefore, elected the GPL

 * Version 2 license, then the option applies only if the new code is

 * made subject to such option by the copyright holder.

 *

 * Contributor(s):

 *

 * Portions Copyrighted 2012 Sun Microsystems, Inc.

 */

package org.openide.util.lookup;

import java.util.Collections;

import java.util.concurrent.atomic.AtomicInteger;

import java.util.regex.Matcher;

import java.util.regex.Pattern;

import org.netbeans.junit.NbTestCase;

import org.openide.util.Lookup;

import org.openide.util.Lookup.Result;

import org.openide.util.LookupEvent;

import org.openide.util.LookupListener;

/**

 *

 * @author Jaroslav Tulach <jtulach@netbeans.org>

 */

public class DeepProxyTest extends NbTestCase implements LookupListener {

    private ProxyLookup proxy;

    private int cnt;

    private int size;

    private AtomicInteger share;

    public DeepProxyTest(String name) {

        super(name);

    }

    @Override

    protected void setUp() throws Exception {

        Matcher m = Pattern.compile("[0-9]+").matcher(getName());

        assertTrue("There is a number in " + getName(), m.find());

        size = Integer.parseInt(m.group(0));

        assertTrue("Found", size > 0);

        share = new AtomicInteger(0);

        Lookup[] arr = new Lookup[size];

        for (int i = 0; i < size; i++) {

            arr[i] = new AddingLkp(share);

        }

        proxy = new ProxyLookup(arr);

    }

    public void testDeep1000() {

        Result<Number> res = proxy.lookupResult(Number.class);

        res.addLookupListener(this);

        assertEquals("Empty now", 0, res.allInstances().size());

        share.set(1);

        assertEquals("Right size", size, res.allInstances().size());

        assertEquals("one change is enough", 1, cnt);

    }

    @Override

    public void resultChanged(LookupEvent ev) {

        cnt++;

        if (new Exception().getStackTrace().length > 100) {

            fail("Too deep recursion!");

        }

    }

    private static final class AddingLkp extends AbstractLookup {

        private final AtomicInteger number;

        private final InstanceContent ic;

        public AddingLkp(AtomicInteger number) {

            this(number, new InstanceContent());

        }

        private AddingLkp(AtomicInteger number, InstanceContent ic) {

            super(ic);

            this.number = number;

            this.ic = ic;

        }

        @Override

        protected void beforeLookup(Template<?> template) {

            if (number.get() != 0 && template.getType() == Number.class) {

                ic.set(Collections.singleton(number), null);

            }

        }

    }

}