PhaseListenerExtension.java

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 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
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package org.apache.myfaces.extensions.cdi.javaee.jsf.impl.listener.phase;

import org.apache.myfaces.extensions.cdi.javaee.jsf.api.listener.phase.JsfPhaseListener;
import org.apache.myfaces.extensions.cdi.javaee.jsf.impl.util.JsfUtils;
import org.apache.myfaces.extensions.cdi.core.api.util.ClassUtils;

import javax.enterprise.event.Observes;
import javax.enterprise.inject.spi.Extension;
import javax.enterprise.inject.spi.ProcessAnnotatedType;
import javax.faces.event.PhaseListener;
import java.util.List;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CopyOnWriteArrayList;

/**
 * The PhaseListenerExtension picks up all {@link JsfPhaseListener} annotated
 * beans for later registration as PhaseListeners.
 * We have to maintain this separately for each ContextClassLoader since it
 * is possible that multiple WebApps start up in parallel.
 * @author Gerhard Petracek
 */
public class PhaseListenerExtension implements Extension
{
    private static Map<ClassLoader, List<PhaseListener>> phaseListeners = 
            new ConcurrentHashMap<ClassLoader,List<PhaseListener>>();

    public void filterJsfPhaseListeners(@Observes ProcessAnnotatedType processAnnotatedType)
    {
        if (processAnnotatedType.getAnnotatedType().isAnnotationPresent(JsfPhaseListener.class))
        {
            //TODO check config if phase-listener is deactivated
            addPhaseListener(processAnnotatedType);

            processAnnotatedType.veto();
        }
    }

    private void addPhaseListener(ProcessAnnotatedType processAnnotatedType)
    {
        PhaseListener newPhaseListener = createPhaseListenerInstance(processAnnotatedType);

        try
        {
            JsfUtils.registerPhaseListener(newPhaseListener);
        }
        catch (IllegalStateException e)
        {
            // current workaround some servers
            addPhaseListener(newPhaseListener);
        }
    }

    private void addPhaseListener(PhaseListener newPhaseListener)
    {
        ClassLoader cl = ClassUtils.getClassLoader(null);

        List<PhaseListener> plList = phaseListeners.get(cl);

        if (plList == null)
        {
            plList = new CopyOnWriteArrayList<PhaseListener>();
            phaseListeners.put(cl, plList);
        }
        plList.add(newPhaseListener);
    }

    private PhaseListener createPhaseListenerInstance(ProcessAnnotatedType processAnnotatedType)
    {
        return ClassUtils.tryToInstantiateClass(
                processAnnotatedType.getAnnotatedType().getJavaClass(), PhaseListener.class);
    }

    //current workaround some servers
    public static List<PhaseListener> consumePhaseListeners()
    {
        ClassLoader cl = ClassUtils.getClassLoader(null);
        List<PhaseListener> plList = phaseListeners.get(cl);

        if(plList != null && ! plList.isEmpty())
        {
            List<PhaseListener> result = new ArrayList<PhaseListener>(plList.size());
            result.addAll(plList);
            plList.clear();
            return result;
        }
        return Collections.emptyList();
    }
}