org.opencms.ui.client.CmsPollServerConnector Maven / Gradle / Ivy
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/*
* This library is part of OpenCms -
* the Open Source Content Management System
*
* Copyright (c) Alkacon Software GmbH & Co. KG (http://www.alkacon.com)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* For further information about Alkacon Software, please see the
* company website: http://www.alkacon.com
*
* For further information about OpenCms, please see the
* project website: http://www.opencms.org
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package org.opencms.ui.client;
import org.opencms.ui.components.extensions.CmsPollServerExtension;
import org.opencms.ui.shared.rpc.I_CmsPollServerRpc;
import com.google.gwt.core.client.Scheduler;
import com.google.gwt.core.client.Scheduler.RepeatingCommand;
import com.google.gwt.event.logical.shared.AttachEvent;
import com.google.gwt.event.logical.shared.AttachEvent.Handler;
import com.google.gwt.user.client.ui.Widget;
import com.vaadin.client.ComponentConnector;
import com.vaadin.client.ServerConnector;
import com.vaadin.client.extensions.AbstractExtensionConnector;
import com.vaadin.shared.ui.Connect;
/**
* This connector will manipulate the CSS classes of the extended widget depending on the scroll position.
*/
@Connect(CmsPollServerExtension.class)
public class CmsPollServerConnector extends AbstractExtensionConnector {
/** Polls the server. */
protected class PollingCommand implements RepeatingCommand {
/** If polling is cancelled. */
private boolean m_cancelled;
/**
* @see com.google.gwt.core.client.Scheduler.RepeatingCommand#execute()
*/
public boolean execute() {
if (!m_cancelled) {
try {
m_rpc.poll();
} catch (@SuppressWarnings("unused") Throwable t) {
m_cancelled = true;
}
}
return !m_cancelled;
}
/**
* Cancels polling.
*/
void cancel() {
m_cancelled = true;
}
}
/** The polling delay in milliseconds. */
private static final int POLLING_DELAY_MS = 30 * 1000;
/** The serial version id. */
private static final long serialVersionUID = -3661096843568550285L;
/** The RPC proxy. */
I_CmsPollServerRpc m_rpc;
/** The polling command. */
private PollingCommand m_command;
/** The widget to enhance. */
private Widget m_widget;
/**
* Constructor.
*/
public CmsPollServerConnector() {
m_rpc = getRpcProxy(I_CmsPollServerRpc.class);
}
/**
* @see com.vaadin.client.extensions.AbstractExtensionConnector#extend(com.vaadin.client.ServerConnector)
*/
@Override
protected void extend(ServerConnector target) {
// Get the extended widget
m_widget = ((ComponentConnector)target).getWidget();
m_widget.addAttachHandler(new Handler() {
public void onAttachOrDetach(AttachEvent event) {
if (event.isAttached()) {
startPolling();
} else {
stopPolling();
}
}
});
startPolling();
}
/**
* Starts polling the server.
*/
void startPolling() {
m_rpc.poll();
if (m_command == null) {
m_command = new PollingCommand();
Scheduler.get().scheduleFixedDelay(m_command, POLLING_DELAY_MS);
}
}
/**
* Stops polling the server.
*/
void stopPolling() {
if (m_command != null) {
m_command.cancel();
m_command = null;
}
}
}