org.mihalis.opal/src/main/java/org/mihalis/opal/breadcrumb/Breadcrumb.java

/*******************************************************************************
 * Copyright (c) 2012 Laurent CARON. 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: 
 *     Laurent CARON (laurent.caron at gmail dot com) - initial API and implementation
 *******************************************************************************/
package org.mihalis.opal.breadcrumb;

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

import org.eclipse.swt.SWT;
import org.eclipse.swt.SWTException;
import org.eclipse.swt.events.PaintEvent;
import org.eclipse.swt.events.PaintListener;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.widgets.Canvas;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.Widget;
import org.mihalis.opal.utils.SWTGraphicUtil;

/**
 * Instances of this class support the layout of selectable
 * bar items displayed in a bread crumb.
 * <p>
 * The item children that may be added to instances of this class
 * must be of type <code>BreadcrumbItem</code>.
 * </p>
 * <p>
 * <dl>
 * <dt><b>Styles:</b></dt>
 * <dd>BORDER</dd>
 * <dt><b>Events:</b></dt>
 * <dd>(none)</dd>
 * </dl>
 *
 */
public class Breadcrumb extends Canvas {

	/** The Constant IS_BUTTON_PRESSED. */
	private static final String IS_BUTTON_PRESSED = Breadcrumb.class.toString() + "_pressed";
	
	/** The items. */
	private final List<BreadcrumbItem> items;
	
	/** The start gradient color. */
	private static Color START_GRADIENT_COLOR = SWTGraphicUtil.getColorSafely(255, 255, 255);
	
	/** The end gradient color. */
	private static Color END_GRADIENT_COLOR = SWTGraphicUtil.getColorSafely(224, 224, 224);
	
	/** The border color. */
	static Color BORDER_COLOR = SWTGraphicUtil.getColorSafely(128, 128, 128);
	
	/** The BORDE r_ colo r_1. */
	static Color BORDER_COLOR_1 = SWTGraphicUtil.getColorSafely(212, 212, 212);
	
	/** The BORDE r_ colo r_2. */
	static Color BORDER_COLOR_2 = SWTGraphicUtil.getColorSafely(229, 229, 229);
	
	/** The BORDE r_ colo r_3. */
	static Color BORDER_COLOR_3 = SWTGraphicUtil.getColorSafely(243, 243, 243);
	
	/** The has border. */
	boolean hasBorder = false;

	/**
	 * Constructs a new instance of this class given its parent and a style
	 * value describing its behavior and appearance.
	 * <p>
	 * The style value is either one of the style constants defined in class
	 * <code>SWT</code> which is applicable to instances of this class, or must
	 * be built by <em>bitwise OR</em>'ing together (that is, using the
	 * <code>int</code> "|" operator) two or more of those <code>SWT</code>
	 * style constants. The class description lists the style constants that are
	 * applicable to the class. Style bits are also inherited from superclasses.
	 * </p>
	 *
	 * @param parent a composite control which will be the parent of the new
	 *            instance (cannot be null)
	 * @param style the style of control to construct
	 * @see Widget#getStyle()
	 * @exception IllegalArgumentException <ul>
	 *                <li>ERROR_NULL_ARGUMENT - if the parent is null</li>
	 *                </ul>
	 * @exception SWTException <ul>
	 *                <li>ERROR_THREAD_INVALID_ACCESS - if not called from the
	 *                thread that created the parent</li>
	 *                <li>ERROR_INVALID_SUBCLASS - if this class is not an
	 *                allowed subclass</li>
	 *                </ul>
	 */
	public Breadcrumb(final Composite parent, final int style) {
		super(parent, checkStyle(style) | SWT.DOUBLE_BUFFERED);
		this.items = new ArrayList<BreadcrumbItem>();
		this.hasBorder = (style & SWT.BORDER) != 0;
		addListeners();
	}

	/**
	 * Check style.
	 *
	 * @param style the style
	 * @return the int
	 */
	private static int checkStyle(final int style) {
		if ((style & SWT.BORDER) != 0) {
			return style & ~SWT.BORDER;
		}
		return 0;
	}

	/**
	 * Adds the listeners.
	 */
	private void addListeners() {
		addMouseDownListener();
		addMouseUpListener();
		addMouseHoverListener();
		addPaintListener(new PaintListener() {
			@Override
			public void paintControl(final PaintEvent e) {
				Breadcrumb.this.paintControl(e);
			}
		});
	}

	/**
	 * Adds the mouse down listener.
	 */
	private void addMouseDownListener() {
		addListener(SWT.MouseDown, new Listener() {
			@Override
			public void handleEvent(final Event event) {
				for (final BreadcrumbItem item : Breadcrumb.this.items) {
					if (item.getBounds().contains(event.x, event.y)) {
						final boolean isToggle = (item.getStyle() & SWT.TOGGLE) != 0;
						final boolean isPush = (item.getStyle() & SWT.PUSH) != 0;
						if (isToggle || isPush) {
							item.setSelection(!item.getSelection());
							redraw();
							update();
						}
						item.setData(IS_BUTTON_PRESSED, "*");
						return;
					}
				}
			}
		});
	}

	/**
	 * Adds the mouse up listener.
	 */
	private void addMouseUpListener() {
		addListener(SWT.MouseUp, new Listener() {
			@Override
			public void handleEvent(final Event event) {
				for (final BreadcrumbItem item : Breadcrumb.this.items) {
					if (item.getBounds().contains(event.x, event.y)) {
						if (item.getData(IS_BUTTON_PRESSED) == null) {
							// The button was not pressed
							return;
						}
						item.setData(IS_BUTTON_PRESSED, null);

						if ((item.getStyle() & SWT.PUSH) != 0) {
							item.setSelection(false);
						}

						if ((item.getStyle() & (SWT.TOGGLE | SWT.PUSH)) != 0) {
							item.fireSelectionEvent();
							redraw();
							update();
						}
						return;
					}
				}
			}
		});
	}

	/**
	 * Adds the mouse hover listener.
	 */
	private void addMouseHoverListener() {
		addListener(SWT.MouseHover, new Listener() {
			@Override
			public void handleEvent(final Event event) {
				for (final BreadcrumbItem item : Breadcrumb.this.items) {
					if (item.getBounds().contains(event.x, event.y)) {
						setToolTipText(item.getTooltipText() == null ? "" : item.getTooltipText());
						return;
					}
				}
			}
		});
	}

	/**
	 * Paint the component.
	 *
	 * @param e event
	 */
	private void paintControl(final PaintEvent e) {
		final GC gc = e.gc;
		gc.setAdvanced(true);
		gc.setAntialias(SWT.ON);

		final int width = getSize().x;
		final int height = getSize().y;

		drawBackground(gc, width, height);
		final Iterator<BreadcrumbItem> it = this.items.iterator();
		int x = 0;
		while (it.hasNext()) {
			final BreadcrumbItem item = it.next();
			item.setGc(gc).setToolbarHeight(height).setIsLastItemOfTheBreadCrumb(!it.hasNext());
			item.drawButtonAtPosition(x);
			x += item.getWidth();
		}
	}

	/**
	 * Draw background.
	 *
	 * @param gc the gc
	 * @param width the width
	 * @param height the height
	 */
	private void drawBackground(final GC gc, final int width, final int height) {
		gc.setForeground(START_GRADIENT_COLOR);
		gc.setBackground(END_GRADIENT_COLOR);
		gc.fillGradientRectangle(0, 0, width, height, true);

		if (this.hasBorder) {
			gc.setForeground(BORDER_COLOR);
			gc.drawRectangle(0, 0, width - 1, height - 1);
		}
	}

	/**
	 * Add an item to the toolbar.
	 *
	 * @param item roundedToolItem to add
	 */
	void addItem(final BreadcrumbItem item) {
		this.items.add(item);
	}

	/**
	 * 
	 *
	 * @param wHint the w hint
	 * @param hHint the h hint
	 * @param changed the changed
	 * @return the point
	 * @see org.eclipse.swt.widgets.Composite#computeSize(int, int, boolean)
	 */
	@Override
	public Point computeSize(final int wHint, final int hHint, final boolean changed) {
		int width = 0, height = 0;
		for (final BreadcrumbItem item : this.items) {
			width += item.getWidth();
			height = Math.max(height, item.getHeight());
		}
		return new Point(Math.max(width, wHint), Math.max(height, hHint));
	}

	/**
	 * Returns the item at the given, zero-relative index in the
	 * receiver. Throws an exception if the index is out of range.
	 *
	 * @param index the index of the item to return
	 * @return the item at the given index
	 *
	 * @exception IllegalArgumentException <ul>
	 *    <li>ERROR_INVALID_RANGE - if the index is not between 0 and the number of elements in the list minus 1 (inclusive)</li>
	 * </ul>
	 * @exception SWTException <ul>
	 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
	 * </ul>
	 */
	public BreadcrumbItem getItem(final int index) {
		checkWidget();
		if (index < 0 || index > this.items.size()) {
			SWT.error(SWT.ERROR_INVALID_ARGUMENT);
		}
		return this.items.get(index);
	}

	/**
	 * Returns the item at the given point in the receiver
	 * or null if no such item exists. The point is in the
	 * coordinate system of the receiver.
	 *
	 * @param point the point used to locate the item
	 * @return the item at the given point
	 *
	 * @exception IllegalArgumentException <ul>
	 *    <li>ERROR_NULL_ARGUMENT - if the point is null</li>
	 * </ul>
	 * @exception SWTException <ul>
	 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
	 * </ul>
	 */
	public BreadcrumbItem getItem(final Point point) {
		checkWidget();
		for (final BreadcrumbItem item : this.items) {
			if (item.getBounds().contains(point)) {
				return item;
			}
		}
		return null;
	}

	/**
	 * Returns the number of items contained in the receiver.
	 *
	 * @return the number of items
	 *
	 * @exception SWTException <ul>
	 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
	 * </ul>
	 */
	public int getItemCount() {
		checkWidget();
		return this.items.size();
	}

	/**
	 * Returns an array of <code>BreadcrumbItem</code>s which are the items
	 * in the receiver. 
	 * <p>
	 * Note: This is not the actual structure used by the receiver
	 * to maintain its list of items, so modifying the array will
	 * not affect the receiver. 
	 * </p>
	 *
	 * @return the items in the receiver
	 *
	 * @exception SWTException <ul>
	 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
	 * </ul>
	 */
	public BreadcrumbItem[] getItems() {
		checkWidget();
		return this.items.toArray(new BreadcrumbItem[this.items.size()]);
	}

	/**
	 * Searches the receiver's list starting at the first item
	 * (index 0) until an item is found that is equal to the 
	 * argument, and returns the index of that item. If no item
	 * is found, returns -1.
	 *
	 * @param item the search item
	 * @return the index of the item
	 *
	 * @exception IllegalArgumentException <ul>
	 *    <li>ERROR_NULL_ARGUMENT - if the item is null</li>
	 *    <li>ERROR_INVALID_ARGUMENT - if the item has been disposed</li>
	 * </ul>
	 * @exception SWTException <ul>
	 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
	 * </ul>
	 */
	public int indexOf(final BreadcrumbItem item) {
		checkWidget();
		return this.items.indexOf(item);
	}

	/**
	 * Remove an item to the toolbar.
	 *
	 * @param item item to remove
	 */
	public void removeItem(final BreadcrumbItem item) {
		this.items.remove(item);
	}

}