org.wicketstuff.push.timer.TimerPushBehavior.java Source code

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Here is the source code for org.wicketstuff.push.timer.TimerPushBehavior.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 under the License.
 */
package org.wicketstuff.push.timer;

import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

import org.apache.wicket.Component;
import org.apache.wicket.ajax.AbstractAjaxTimerBehavior;
import org.apache.wicket.ajax.AjaxRequestTarget;
import org.apache.wicket.markup.head.IHeaderResponse;
import org.apache.wicket.markup.head.JavaScriptHeaderItem;
import org.apache.wicket.markup.head.OnEventHeaderItem;
import org.apache.wicket.request.cycle.RequestCycle;
import org.apache.wicket.request.http.WebRequest;
import org.apache.wicket.util.time.Duration;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.wicketstuff.push.IPushEventContext;
import org.wicketstuff.push.IPushEventHandler;
import org.wicketstuff.push.IPushNode;

/**
 * @author <a href="http://sebthom.de/">Sebastian Thomschke</a>
 */
@SuppressWarnings({ "rawtypes", "unchecked" })
public class TimerPushBehavior extends AbstractAjaxTimerBehavior {
    private static final long serialVersionUID = 1L;

    private static final Logger LOG = LoggerFactory.getLogger(TimerPushBehavior.class);

    private final Map<TimerPushNode, IPushEventHandler> handlers = new HashMap<TimerPushNode, IPushEventHandler>(2);

    TimerPushBehavior(final Duration pollingInterval) {
        super(pollingInterval);
    }

    <EventType> TimerPushNode<EventType> addNode(final IPushEventHandler<EventType> pushEventHandler,
            final Duration pollingInterval) {
        if (pollingInterval.lessThan(getUpdateInterval()))
            setUpdateInterval(pollingInterval);

        final TimerPushNode<EventType> node = new TimerPushNode<EventType>(pollingInterval);
        handlers.put(node, pushEventHandler);
        return node;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    protected void onTimer(final AjaxRequestTarget target) {
        if (isStopped()) {
            getComponent().remove(this);
            return;
        }

        final TimerPushService pushService = TimerPushService.get(target.getPage().getApplication());

        final WebRequest request = (WebRequest) RequestCycle.get().getRequest();

        if (!request.getRequestParameters().getParameterValue("unload").isNull())
            // if the page is unloaded notify the pushService to disconnect all push nodes
            for (final TimerPushNode<?> node : handlers.keySet())
                pushService.onDisconnect(node);

        else
            // retrieve all collected events and process them
            for (final Entry<TimerPushNode, IPushEventHandler> entry : handlers.entrySet()) {
                final TimerPushNode node = entry.getKey();
                for (final IPushEventContext<?> ctx : (List<IPushEventContext<?>>) pushService.pollEvents(node))
                    try {
                        entry.getValue().onEvent(target, ctx.getEvent(), node, ctx);
                    } catch (final RuntimeException ex) {
                        LOG.error("Failed while processing event", ex);
                    }
            }
    }

    /**
     * @return the number of handlers after the removal
     */
    int removeNode(final IPushNode<?> node) {
        handlers.remove(node);

        // adjust the polling interval based on the fastest remaining node
        Duration newPollingInterval = Duration.MAXIMUM;
        for (final TimerPushNode n : handlers.keySet())
            if (n.getPollingInterval().lessThan(newPollingInterval))
                newPollingInterval = n.getPollingInterval();
        setUpdateInterval(newPollingInterval);

        return handlers.size();
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void renderHead(final Component c, final IHeaderResponse response) {
        super.renderHead(c, response);

        if (!isStopped()) {
            // install an on-unload handler
            response.render(JavaScriptHeaderItem.forScript("history.navigationMode = 'compatible';",
                    "Opera on-unload support"));
            response.render(OnEventHeaderItem.forScript("window", "unload",
                    "Wicket.Ajax.get({'u': '" + getCallbackUrl().toString() + "&unload=1'});"));
        }
    }
}