org.opencms.ui.client.CmsMaxHeightConnector.java Source code

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Here is the source code for org.opencms.ui.client.CmsMaxHeightConnector.java

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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.gwt.client.util.CmsDebugLog;
import org.opencms.ui.components.extensions.CmsMaxHeightExtension;
import org.opencms.ui.shared.components.CmsMaxHeightState;
import org.opencms.ui.shared.rpc.I_CmsMaxHeightServerRpc;

import com.google.gwt.core.client.JavaScriptObject;
import com.google.gwt.dom.client.Element;
import com.google.gwt.dom.client.Style.Unit;
import com.google.gwt.user.client.ui.Widget;
import com.vaadin.client.ComponentConnector;
import com.vaadin.client.ServerConnector;
import com.vaadin.client.communication.StateChangeEvent;
import com.vaadin.client.communication.StateChangeEvent.StateChangeHandler;
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.<p>
 */
@Connect(CmsMaxHeightExtension.class)
public class CmsMaxHeightConnector extends AbstractExtensionConnector {

    /** The serial version id. */
    private static final long serialVersionUID = -3661096843568550285L;

    /** The currently set height. */
    private int m_currentHeight;

    /** Flag indicating the required height is currently being evaluated. */
    private boolean m_evaluating;

    /** The native mutation observer. */
    private JavaScriptObject m_mutationObserver;

    /** The RPC proxy. */
    private I_CmsMaxHeightServerRpc m_rpc;

    /** Flag which is set when this connector is unregistered. */
    private boolean m_unregistered;

    /** The widget to enhance. */
    private Widget m_widget;

    /**
     * Constructor.<p>
     */
    public CmsMaxHeightConnector() {
        m_currentHeight = -1;
        m_rpc = getRpcProxy(I_CmsMaxHeightServerRpc.class);
    }

    /**
     * @see com.vaadin.client.ui.AbstractConnector#getState()
     */
    @Override
    public CmsMaxHeightState getState() {

        return (CmsMaxHeightState) super.getState();
    }

    /**
     * @see com.vaadin.client.ui.AbstractConnector#onUnregister()
     */
    @Override
    public void onUnregister() {

        super.onUnregister();
        m_unregistered = true;
        removeObserver();
    }

    /**
     * @see com.vaadin.client.extensions.AbstractExtensionConnector#extend(com.vaadin.client.ServerConnector)
     */
    @Override
    protected void extend(ServerConnector target) {

        target.isEnabled();

        // Get the extended widget
        m_widget = ((ComponentConnector) target).getWidget();
        addMutationObserver(m_widget.getElement());
        addStateChangeHandler(new StateChangeHandler() {

            @SuppressWarnings("synthetic-access")
            public void onStateChanged(StateChangeEvent stateChangeEvent) {

                m_currentHeight = -1;
                handleMutation();
            }
        });
    }

    /**
     * Handles the widget mutation.<p>
     */
    protected void handleMutation() {

        if (m_unregistered) {
            removeObserver();
            return;
        }
        int maxHeight = getState().getMaxHeight();
        if (m_currentHeight > 0) {
            removeObserver();
            // clear height
            m_widget.getElement().getStyle().clearHeight();
            if ((m_widget.getOffsetHeight() + 10) < m_currentHeight) {
                m_currentHeight = -1;
                m_rpc.fixHeight(m_currentHeight);
            } else {
                m_widget.getElement().getStyle().setHeight(m_currentHeight, Unit.PX);
            }

            addMutationObserver(m_widget.getElement());
        } else if ((maxHeight > 0) && (m_widget.getOffsetHeight() > maxHeight)) {
            m_currentHeight = maxHeight;
            m_rpc.fixHeight(m_currentHeight);
        }
    }

    /**
     * Adds a native mutation observer to the widget element.<p>
     *
     * @param element the element
     */
    private native void addMutationObserver(Element element)/*-{
                                                            var self = this;
                                                            var observer = new MutationObserver(
                                                            function(mutations) {
                                                            self.@org.opencms.ui.client.CmsMaxHeightConnector::handleMutation()();
                                                            });
                                                            this.@org.opencms.ui.client.CmsMaxHeightConnector::m_mutationObserver = observer;
                                                                
                                                            // configuration of the observer:
                                                            var config = {
                                                            attributes : true,
                                                            childList : true,
                                                            characterData : true,
                                                            subtree : true
                                                            };
                                                                
                                                            // pass in the target node, as well as the observer options
                                                            observer.observe(element, config);
                                                            }-*/;

    /**
     * Removes the mutation observer.<p>
     */
    private native void removeObserver()/*-{
                                        if (this.@org.opencms.ui.client.CmsMaxHeightConnector::m_mutationObserver != null) {
                                        this.@org.opencms.ui.client.CmsMaxHeightConnector::m_mutationObserver
                                        .disconnect();
                                        this.@org.opencms.ui.client.CmsMaxHeightConnector::m_mutationObserver = null;
                                        }
                                        }-*/;
}