org.eclipse.jface.snippets.viewers.Snippet030VirtualLazyTableViewer.java Source code

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Here is the source code for org.eclipse.jface.snippets.viewers.Snippet030VirtualLazyTableViewer.java

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/*******************************************************************************
 * Copyright (c) 2006, 2014 Tom Schindl and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     Tom Schindl - initial API and implementation
 *     Lars Vogel <Lars.Vogel@gmail.com> - Bug 414565
 *******************************************************************************/

package org.eclipse.jface.snippets.viewers;

import org.eclipse.jface.viewers.ILazyContentProvider;
import org.eclipse.jface.viewers.LabelProvider;
import org.eclipse.jface.viewers.TableViewer;
import org.eclipse.jface.viewers.Viewer;
import org.eclipse.swt.SWT;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Table;
import org.eclipse.swt.widgets.TableColumn;

/**
 * A simple TableViewer to demonstrate usage of an ILazyContentProvider. You can
 * compare this snippet to the Snippet029VirtualTableViewer to see the small but
 * needed difference.
 *
 */
public class Snippet030VirtualLazyTableViewer {
    private class MyContentProvider implements ILazyContentProvider {
        private TableViewer viewer;
        private MyModel[] elements;

        public MyContentProvider(TableViewer viewer) {
            this.viewer = viewer;
        }

        @Override
        public void dispose() {

        }

        @Override
        public void inputChanged(Viewer viewer, Object oldInput, Object newInput) {
            this.elements = (MyModel[]) newInput;
        }

        @Override
        public void updateElement(int index) {
            viewer.replace(elements[index], index);
        }

    }

    public class MyModel {
        public int counter;

        public MyModel(int counter) {
            this.counter = counter;
        }

        @Override
        public String toString() {
            return "Item " + this.counter;
        }
    }

    public Snippet030VirtualLazyTableViewer(Shell shell) {
        final TableViewer v = new TableViewer(shell, SWT.VIRTUAL);
        v.setLabelProvider(new LabelProvider());
        v.setContentProvider(new MyContentProvider(v));
        v.setUseHashlookup(true);
        createColumn(v.getTable(), "Column 1");
        MyModel[] model = createModel();
        v.setInput(model);
        v.setItemCount(model.length); // This is the difference when using a
        // ILazyContentProvider

        v.getTable().setLinesVisible(true);
    }

    public void createColumn(Table tb, String text) {
        TableColumn column = new TableColumn(tb, SWT.NONE);
        column.setWidth(100);
        column.setText(text);
        tb.setHeaderVisible(true);
    }

    private MyModel[] createModel() {
        MyModel[] elements = new MyModel[10000];

        for (int i = 0; i < 10000; i++) {
            elements[i] = new MyModel(i);
        }

        return elements;
    }

    public static void main(String[] args) {
        Display display = new Display();
        Shell shell = new Shell(display);
        shell.setLayout(new FillLayout());
        new Snippet030VirtualLazyTableViewer(shell);
        shell.open();

        while (!shell.isDisposed()) {
            if (!display.readAndDispatch())
                display.sleep();
        }

        display.dispose();

    }

}