/*******************************************************************************
* Copyright (c) 2004, 2015 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.jface.viewers.deferred;
import org.eclipse.swt.widgets.Control;
/**
* Wrapper for a virtual-table-like widget. Contains all methods needed for lazy updates.
* The JFace algorithms for deferred or lazy content providers should talk to this class
* instead of directly to a TableViewer. This will allow them to be used with other virtual
* viewers and widgets in the future.
*
* <p>
* For example, if SWT starts to support virtual Lists in the future, it should be possible
* to create an adapter from <code>AbstractVirtualTable</code> to <code>ListViewer</code> in
* order to reuse the existing algorithms for deferred updates.
* </p>
*
* <p>
* This is package visiblity by design. It would only need to be made public if there was
* a demand to use the deferred content provider algorithms like
* <code>BackgroundContentProvider</code> with non-JFace viewers.
* </p>
*
* @since 3.1
*/
abstract class AbstractVirtualTable {
/**
* Tells the receiver that the item at given row has changed. This may indicate
* that a different element is now at this row, but does not necessarily indicate
* that the element itself has changed. The receiver should request information for
* this row the next time it becomes visibile.
*
* @param index row to clear
*/
public abstract void clear(int index);
/**
* Notifies the receiver that the given element is now located at the given index.
*
* @param element object located at the row
* @param itemIndex row number
*/
public abstract void replace(Object element, int itemIndex);
/**
* Sets the item count for this table
*
* @param total new total number of items
*/
public abstract void setItemCount(int total);
/**
* Returns the index of the top item visible in the table
*
* @return the index of the top item visible in the table
*/
public abstract int getTopIndex();
/**
* Returns the number of items currently visible in the table. This is
* the size of the currently visible window, not the total size of the table.
*
* @return the number of items currently visible in the table
*/
public abstract int getVisibleItemCount();
/**
* Returns the total number of items in the table
*
* @return the total number of items in the table
*/
public abstract int getItemCount();
/**
* Returns the SWT control that this API is wrappering.
* @return Control.
*/
public abstract Control getControl();
}