examples/org.eclipse.jface.snippets/Eclipse JFace Snippets/org/eclipse/jface/snippets/viewers/Snippet041TableViewerAlternatingColors.java

/*******************************************************************************
 * Copyright (c) 2007, 2015 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@vogella.com> - Bug 413427, 475361
 *     Jeanderson Candido (http://jeandersonbc.github.io) - Bug 414565
 *     Jan-Ove Weichel <janove.weichel@vogella.com> - Bug 481490
 *******************************************************************************/

package org.eclipse.jface.snippets.viewers;

import java.util.ArrayList;
import java.util.List;

import org.eclipse.jface.viewers.ArrayContentProvider;
import org.eclipse.jface.viewers.ColumnLabelProvider;
import org.eclipse.jface.viewers.TableViewer;
import org.eclipse.jface.viewers.TableViewerColumn;
import org.eclipse.jface.viewers.Viewer;
import org.eclipse.jface.viewers.ViewerCell;
import org.eclipse.jface.viewers.ViewerFilter;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.TableItem;

/**
 * Demonstrate alternating row colors using new JFace 3.3 API
 *
 * @author Tom Schindl &lt;tom.schindl@bestsolution.at&gt;
 *
 */
public class Snippet041TableViewerAlternatingColors {

	public static class MyModel {
		public int counter;

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

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

	private class OptimizedIndexSearcher {
		private int lastIndex = 0;

		public boolean isEven(TableItem item) {
			TableItem[] items = item.getParent().getItems();

			// 1. Search the next ten items
			for (int i = lastIndex; i < items.length && lastIndex + 10 > i; i++) {
				if (items[i] == item) {
					lastIndex = i;
					return lastIndex % 2 == 0;
				}
			}

			// 2. Search the previous ten items
			for (int i = lastIndex; i < items.length && lastIndex - 10 > i; i--) {
				if (items[i] == item) {
					lastIndex = i;
					return lastIndex % 2 == 0;
				}
			}

			// 3. Start from the beginning
			for (int i = 0; i < items.length; i++) {
				if (items[i] == item) {
					lastIndex = i;
					return lastIndex % 2 == 0;
				}
			}

			return false;
		}
	}

	final private OptimizedIndexSearcher searcher = new OptimizedIndexSearcher();

	public Snippet041TableViewerAlternatingColors(Shell shell) {

		final TableViewer viewer = new TableViewer(shell, SWT.BORDER
				| SWT.FULL_SELECTION | SWT.VIRTUAL);

		viewer.setContentProvider(ArrayContentProvider.getInstance());
		String[] labels = { "Column 1", "Column 2" };
		for (String label : labels) {
			createColumnFor(viewer, label);
		}
		viewer.setInput(createModel());
		viewer.getTable().setLinesVisible(true);
		viewer.getTable().setHeaderVisible(true);

		Button b = new Button(shell, SWT.PUSH);
		b.setText("Press to toggle filter");
		b.addSelectionListener(createAdapterFor(viewer));
	}

	private SelectionAdapter createAdapterFor(final TableViewer viewer) {
		return new SelectionAdapter() {
			boolean b = true;

			@Override
			public void widgetSelected(SelectionEvent e) {
				if (b) {
					viewer.setFilters(createFilterForViewer());
					b = false;

				} else {
					viewer.setFilters();
					b = true;
				}
			}
		};
	}

	private ViewerFilter createFilterForViewer() {
		return new ViewerFilter() {

			@Override
			public boolean select(Viewer viewer, Object parentElement,
					Object element) {

				return ((MyModel) element).counter % 2 == 0;
			}
		};
	}

	private TableViewerColumn createColumnFor(TableViewer viewer, String label) {
		TableViewerColumn column;
		column = new TableViewerColumn(viewer, SWT.NONE);
		column.getColumn().setWidth(200);
		column.getColumn().setText(label);
		column.setLabelProvider(createLabelProviderFor(viewer));
		return column;
	}

	private ColumnLabelProvider createLabelProviderFor(final TableViewer viewer) {
		return new ColumnLabelProvider() {
			boolean isEvenIdx = true;

			@Override
			public Color getBackground(Object element) {
				Color grayColor = viewer.getTable().getDisplay()
						.getSystemColor(SWT.COLOR_GRAY);

				return (isEvenIdx ? null : grayColor);
			}

			@Override
			public void update(ViewerCell cell) {
				isEvenIdx = searcher.isEven((TableItem) cell.getItem());
				super.update(cell);
			}
		};
	}

	private List<MyModel> createModel() {
		List<MyModel> elements = new ArrayList<>();
		for (int i = 0; i < 100000; i++) {
			elements.add(new MyModel(i));
		}
		return elements;
	}

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		Display display = new Display();

		Shell shell = new Shell(display);
		shell.setLayout(new FillLayout());
		new Snippet041TableViewerAlternatingColors(shell);
		shell.open();

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

	}

}