org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/breadcrumb/BreadcrumbViewer.java - jdt/eclipse.jdt.ui - Git at Google

 /*******************************************************************************
  * Copyright (c) 2008, 2011 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
  *     Fabio Zadrozny - Bug 465666
  *******************************************************************************/
 package org.eclipse.jdt.internal.ui.javaeditor.breadcrumb;

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

 import org.eclipse.swt.SWT;
 import org.eclipse.swt.events.DisposeEvent;
 import org.eclipse.swt.events.MenuDetectEvent;
 import org.eclipse.swt.events.MenuDetectListener;
 import org.eclipse.swt.events.TraverseEvent;
 import org.eclipse.swt.events.TraverseListener;
 import org.eclipse.swt.graphics.Image;
 import org.eclipse.swt.layout.GridData;
 import org.eclipse.swt.layout.GridLayout;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Control;
 import org.eclipse.swt.widgets.Event;
 import org.eclipse.swt.widgets.Listener;
 import org.eclipse.swt.widgets.Shell;
 import org.eclipse.swt.widgets.Widget;

 import org.eclipse.core.runtime.Assert;
 import org.eclipse.core.runtime.ListenerList;

 import org.eclipse.jface.viewers.CellLabelProvider;
 import org.eclipse.jface.viewers.DoubleClickEvent;
 import org.eclipse.jface.viewers.IContentProvider;
 import org.eclipse.jface.viewers.ILabelProvider;
 import org.eclipse.jface.viewers.ISelectionProvider;
 import org.eclipse.jface.viewers.ITreeContentProvider;
 import org.eclipse.jface.viewers.OpenEvent;
 import org.eclipse.jface.viewers.SelectionChangedEvent;
 import org.eclipse.jface.viewers.StructuredSelection;
 import org.eclipse.jface.viewers.StructuredViewer;
 import org.eclipse.jface.viewers.TreeViewer;
 import org.eclipse.jface.viewers.ViewerCell;


 /**
  * A breadcrumb viewer shows a the parent chain of its input element in a list. Each breadcrumb item
  * of that list can be expanded and a sibling of the element presented by the breadcrumb item can be
  * selected.
  * <p>
  * Content providers for breadcrumb viewers must implement the <code>ITreeContentProvider</code>
  * interface.
  * </p>
  * <p>
  * Label providers for breadcrumb viewers must implement the <code>ILabelProvider</code> interface.
  * </p>
  *
  * @since 3.4
  */
 public abstract class BreadcrumbViewer extends StructuredViewer {

 	private static final boolean IS_GTK= "gtk".equals(SWT.getPlatform()); //$NON-NLS-1$

 	private final Composite fContainer;
 	private final ArrayList<BreadcrumbItem> fBreadcrumbItems;
 	private final ListenerList<MenuDetectListener> fMenuListeners;

 	private Image fGradientBackground;
 	private BreadcrumbItem fSelectedItem;
 	private ILabelProvider fToolTipLabelProvider;


 	/**
 	 * Create a new <code>BreadcrumbViewer</code>.
 	 * <p>
 	 * Style is one of:
 	 * <ul>
 	 * <li>SWT.NONE</li>
 	 * <li>SWT.VERTICAL</li>
 	 * <li>SWT.HORIZONTAL</li>
 	 * </ul>
 	 *
 	 * @param parent the container for the viewer
 	 * @param style the style flag used for this viewer
 	 */
 	public BreadcrumbViewer(Composite parent, int style) {
 		fBreadcrumbItems= new ArrayList<>();
 		fMenuListeners= new ListenerList<>();

 		fContainer= new Composite(parent, SWT.NONE);
 		GridData layoutData= new GridData(SWT.FILL, SWT.TOP, true, false);
 		fContainer.setLayoutData(layoutData);
 		fContainer.addTraverseListener(new TraverseListener() {
 			@Override
 			public void keyTraversed(TraverseEvent e) {
 				e.doit= true;
 			}
 		});
 		fContainer.setBackgroundMode(SWT.INHERIT_DEFAULT);
 		fContainer.setData("org.eclipse.e4.ui.css.id", "BreadcrumbComposite"); //$NON-NLS-1$ //$NON-NLS-2$

 		hookControl(fContainer);

 		int columns= 1000;
 		if ((SWT.VERTICAL & style) != 0) {
 			columns= 1;
 		}

 		GridLayout gridLayout= new GridLayout(columns, false);
 		gridLayout.marginWidth= 0;
 		gridLayout.marginHeight= 0;
 		gridLayout.verticalSpacing= 0;
 		gridLayout.horizontalSpacing= 0;
 		fContainer.setLayout(gridLayout);

 		fContainer.addListener(SWT.Resize, new Listener() {
 			@Override
 			public void handleEvent(Event event) {
 				refresh();
 			}
 		});
 	}

 	/**
 	 * Configure the given drop down viewer. The given input is used for the viewers input. Clients
 	 * must at least set the label and the content provider for the viewer.
 	 *
 	 * @param viewer the viewer to configure
 	 * @param input the input for the viewer
 	 */
 	protected abstract void configureDropDownViewer(TreeViewer viewer, Object input);

 	/**
 	 * The tool tip to use for the tool tip labels. <code>null</code> if the viewers label provider
 	 * should be used.
 	 *
 	 * @param toolTipLabelProvider the label provider for the tool tips or <code>null</code>
 	 */
 	public void setToolTipLabelProvider(ILabelProvider toolTipLabelProvider) {
 		fToolTipLabelProvider= toolTipLabelProvider;
 	}

 	/*
 	 * @see org.eclipse.jface.viewers.Viewer#getControl()
 	 */
 	@Override
 	public Control getControl() {
 		return fContainer;
 	}

 	/*
 	 * @see org.eclipse.jface.viewers.StructuredViewer#getRoot()
 	 */
 	@Override
 	protected Object getRoot() {
 		if (fBreadcrumbItems.isEmpty())
 			return null;

 		return fBreadcrumbItems.get(0).getData();
 	}

 	/*
 	 * @see org.eclipse.jface.viewers.StructuredViewer#reveal(java.lang.Object)
 	 */
 	@Override
 	public void reveal(Object element) {
 		//all elements are always visible
 	}

 	/**
 	 * Transfers the keyboard focus into the viewer.
 	 */
 	public void setFocus() {
 		fContainer.setFocus();

 		if (fSelectedItem != null) {
 			fSelectedItem.setFocus(true);
 		} else {
 			if (fBreadcrumbItems.size() == 0)
 				return;

 			BreadcrumbItem item= fBreadcrumbItems.get(fBreadcrumbItems.size() - 1);
 			if (item.getData() == null) {
 				if (fBreadcrumbItems.size() < 2)
 					return;

 				item= fBreadcrumbItems.get(fBreadcrumbItems.size() - 2);
 			}
 			item.setFocus(true);
 		}
 	}

 	/**
 	 * @return true if any of the items in the viewer is expanded
 	 */
 	public boolean isDropDownOpen() {
 		for (int i= 0, size= fBreadcrumbItems.size(); i < size; i++) {
 			BreadcrumbItem item= fBreadcrumbItems.get(i);
 			if (item.isMenuShown())
 				return true;
 		}

 		return false;
 	}

 	/**
 	 * The shell used for the shown drop down or <code>null</code>
 	 * if no drop down is shown at the moment.
 	 *
 	 * @return the drop downs shell or <code>null</code>
 	 */
 	public Shell getDropDownShell() {
 		for (int i= 0, size= fBreadcrumbItems.size(); i < size; i++) {
 			BreadcrumbItem item= fBreadcrumbItems.get(i);
 			if (item.isMenuShown())
 				return item.getDropDownShell();
 		}

 		return null;
 	}

 	/**
 	 * Returns the selection provider which provides the selection of the drop down currently opened
 	 * or <code>null</code> if no drop down is open at the moment.
 	 *
 	 * @return the selection provider of the open drop down or <code>null</code>
 	 */
 	public ISelectionProvider getDropDownSelectionProvider() {
 		for (int i= 0, size= fBreadcrumbItems.size(); i < size; i++) {
 			BreadcrumbItem item= fBreadcrumbItems.get(i);
 			if (item.isMenuShown()) {
 				return item.getDropDownSelectionProvider();
 			}
 		}

 		return null;
 	}

 	/**
 	 * Add the given listener to the set of listeners which will be informed
 	 * when a context menu is requested for a breadcrumb item.
 	 *
 	 * @param listener the listener to add
 	 */
 	public void addMenuDetectListener(MenuDetectListener listener) {
 		fMenuListeners.add(listener);
 	}

 	/**
 	 * Remove the given listener from the set of menu detect listeners.
 	 * Does nothing if the listener is not element of the set.
 	 *
 	 * @param listener the listener to remove
 	 */
 	public void removeMenuDetectListener(MenuDetectListener listener) {
 		fMenuListeners.remove(listener);
 	}

 	/*
 	 * @see org.eclipse.jface.viewers.StructuredViewer#assertContentProviderType(org.eclipse.jface.viewers.IContentProvider)
 	 */
 	@Override
 	protected void assertContentProviderType(IContentProvider provider) {
 		super.assertContentProviderType(provider);
 		Assert.isTrue(provider instanceof ITreeContentProvider);
 	}

 	/*
 	 * @see org.eclipse.jface.viewers.Viewer#inputChanged(java.lang.Object, java.lang.Object)
 	 */
 	@Override
 	protected void inputChanged(Object fInput, Object oldInput) {
 		if (fContainer.isDisposed())
 			return;

 		disableRedraw();
 		try {
 			if (fBreadcrumbItems.size() > 0) {
 				BreadcrumbItem last= fBreadcrumbItems.get(fBreadcrumbItems.size() - 1);
 				last.setIsLastItem(false);
 			}

 			int lastIndex= buildItemChain(fInput);

 			if (lastIndex > 0) {
 				BreadcrumbItem last= fBreadcrumbItems.get(lastIndex - 1);
 				last.setIsLastItem(true);
 			}

 			while (lastIndex < fBreadcrumbItems.size()) {
 				BreadcrumbItem item= fBreadcrumbItems.remove(fBreadcrumbItems.size() - 1);
 				if (item == fSelectedItem) {
 					selectItem(null);
 				}
 				if (item.getData() != null)
 					unmapElement(item.getData());
 				item.dispose();
 			}

 			updateSize();
 			fContainer.layout(true, true);
 		} finally {
 			enableRedraw();
 		}
 	}

 	/*
 	 * @see org.eclipse.jface.viewers.StructuredViewer#doFindInputItem(java.lang.Object)
 	 */
 	@Override
 	protected Widget doFindInputItem(Object element) {
 		if (element == null)
 			return null;

 		if (element == getInput() || element.equals(getInput()))
 			return doFindItem(element);

 		return null;
 	}

 	/*
 	 * @see org.eclipse.jface.viewers.StructuredViewer#doFindItem(java.lang.Object)
 	 */
 	@Override
 	protected Widget doFindItem(Object element) {
 		if (element == null)
 			return null;

 		for (int i= 0, size= fBreadcrumbItems.size(); i < size; i++) {
 			BreadcrumbItem item= fBreadcrumbItems.get(i);
 			if (item.getData() == element || element.equals(item.getData()))
 				return item;
 		}

 		return null;
 	}

 	/*
 	 * @see org.eclipse.jface.viewers.StructuredViewer#doUpdateItem(org.eclipse.swt.widgets.Widget, java.lang.Object, boolean)
 	 */
 	@Override
 	protected void doUpdateItem(Widget widget, Object element, boolean fullMap) {
 		if (widget instanceof BreadcrumbItem) {
 			final BreadcrumbItem item= (BreadcrumbItem) widget;

 			// remember element we are showing
 			if (fullMap) {
 				associate(element, item);
 			} else {
 				Object data= item.getData();
 				if (data != null) {
 					unmapElement(data, item);
 				}
 				item.setData(element);
 				mapElement(element, item);
 			}

 			BreadcrumbViewerRow row= new BreadcrumbViewerRow(this, item);
 			ViewerCell cell= row.getCell(0);

 			((CellLabelProvider) getLabelProvider()).update(cell);

 			item.refreshArrow();

 			if (fToolTipLabelProvider != null) {
 				item.setToolTip(fToolTipLabelProvider.getText(item.getData()));
 			} else {
 				item.setToolTip(cell.getText());
 			}
 		}
 	}

 	/*
 	 * @see org.eclipse.jface.viewers.StructuredViewer#getSelectionFromWidget()
 	 */
 	@Override
 	protected List getSelectionFromWidget() {
 		if (fSelectedItem == null)
 			return Collections.EMPTY_LIST;

 		if (fSelectedItem.getData() == null)
 			return Collections.EMPTY_LIST;

 		ArrayList<Object> result= new ArrayList<>();
 		result.add(fSelectedItem.getData());
 		return result;
 	}

 	/*
 	 * @see org.eclipse.jface.viewers.StructuredViewer#internalRefresh(java.lang.Object)
 	 */
 	@Override
 	protected void internalRefresh(Object element) {

 		disableRedraw();
 		try {
 			BreadcrumbItem item= (BreadcrumbItem) doFindItem(element);
 			if (item == null) {
 				for (int i= 0, size= fBreadcrumbItems.size(); i < size; i++) {
 					BreadcrumbItem item1= fBreadcrumbItems.get(i);
 					item1.refresh();
 				}
 			} else {
 				item.refresh();
 			}
 			if (updateSize())
 				fContainer.layout(true, true);
 		} finally {
 			enableRedraw();
 		}
 	}

 	/*
 	 * @see org.eclipse.jface.viewers.StructuredViewer#setSelectionToWidget(java.util.List, boolean)
 	 */
 	@Override
 	protected void setSelectionToWidget(List l, boolean reveal) {
 		BreadcrumbItem focusItem= null;

 		for (int i= 0, size= fBreadcrumbItems.size(); i < size; i++) {
 			BreadcrumbItem item= fBreadcrumbItems.get(i);
 			if (item.hasFocus())
 				focusItem= item;

 			item.setSelected(false);
 		}

 		if (l == null)
 			return;

 		for (Iterator<?> iterator= l.iterator(); iterator.hasNext();) {
 			Object element= iterator.next();
 			BreadcrumbItem item= (BreadcrumbItem) doFindItem(element);
 			if (item != null) {
 				item.setSelected(true);
 				fSelectedItem= item;
 				if (item == focusItem) {
 					item.setFocus(true);
 				}
 			}
 		}
 	}

 	/**
 	 * Set a single selection to the given item. <code>null</code> to deselect all.
 	 *
 	 * @param item the item to select or <code>null</code>
 	 */
 	void selectItem(BreadcrumbItem item) {
 		if (fSelectedItem != null)
 			fSelectedItem.setSelected(false);

 		fSelectedItem= item;
 		setSelectionToWidget(getSelection(), false);

 		if (item != null) {
 			setFocus();
 		} else {
 			for (int i= 0, size= fBreadcrumbItems.size(); i < size; i++) {
 				BreadcrumbItem listItem= fBreadcrumbItems.get(i);
 				listItem.setFocus(false);
 			}
 		}

 		fireSelectionChanged(new SelectionChangedEvent(this, getSelection()));
 	}

 	/**
 	 * Returns the item count.
 	 *
 	 * @return number of items shown in the viewer
 	 */
 	int getItemCount() {
 		return fBreadcrumbItems.size();
 	}

 	/**
 	 * Returns the item for the given item index.
 	 *
 	 * @param index the index of the item
 	 * @return the item ad the given <code>index</code>
 	 */
 	BreadcrumbItem getItem(int index) {
 		return fBreadcrumbItems.get(index);
 	}

 	/**
 	 * Returns the index of the given item.
 	 *
 	 * @param item the item to search
 	 * @return the index of the item or -1 if not found
 	 */
 	int getIndexOfItem(BreadcrumbItem item) {
 		for (int i= 0, size= fBreadcrumbItems.size(); i < size; i++) {
 			BreadcrumbItem pItem= fBreadcrumbItems.get(i);
 			if (pItem == item)
 				return i;
 		}

 		return -1;
 	}

 	/**
 	 * Notifies all double click listeners.
 	 */
 	void fireDoubleClick() {
 		fireDoubleClick(new DoubleClickEvent(this, getSelection()));
 	}

 	/**
 	 * Notifies all open listeners.
 	 */
 	void fireOpen() {
 		fireOpen(new OpenEvent(this, getSelection()));
 	}

 	/**
 	 * The given element was selected from a drop down menu.
 	 *
 	 * @param element the selected element
 	 */
 	void fireMenuSelection(Object element) {
 		fireOpen(new OpenEvent(this, new StructuredSelection(element)));
 	}

 	/**
 	 * A context menu has been requested for the selected breadcrumb item.
 	 *
 	 * @param event the event issued the menu detection
 	 */
 	void fireMenuDetect(MenuDetectEvent event) {
 		for (MenuDetectListener listener : fMenuListeners) {
 			listener.menuDetected(event);
 		}
 	}

 	/**
 	 * Set selection to the next or previous element if possible.
 	 *
 	 * @param next <code>true</code> if the next element should be selected, otherwise the previous
 	 *            one will be selected
 	 */
 	void doTraverse(boolean next) {
 		if (fSelectedItem == null)
 			return;

 		int index= fBreadcrumbItems.indexOf(fSelectedItem);
 		if (next) {
 			if (index == fBreadcrumbItems.size() - 1) {
 				BreadcrumbItem current= fBreadcrumbItems.get(index);

 				ITreeContentProvider contentProvider= (ITreeContentProvider) getContentProvider();
 				if (!contentProvider.hasChildren(current.getData()))
 					return;

 				current.openDropDownMenu();
 				current.getDropDownShell().setFocus();
 			} else {
 				BreadcrumbItem nextItem= fBreadcrumbItems.get(index + 1);
 				selectItem(nextItem);
 			}
 		} else {
 			if (index == 1) {
 				BreadcrumbItem root= fBreadcrumbItems.get(0);
 				root.openDropDownMenu();
 				root.getDropDownShell().setFocus();
 			} else {
 				selectItem(fBreadcrumbItems.get(index - 1));
 			}
 		}
 	}

 	/**
 	 * Generates the parent chain of the given element.
 	 *
 	 * @param element element to build the parent chain for
 	 * @return the first index of an item in fBreadcrumbItems which is not part of the chain
 	 */
 	private int buildItemChain(Object element) {
 		if (element == null)
 			return 0;

 		ITreeContentProvider contentProvider= (ITreeContentProvider) getContentProvider();
 		Object parent= contentProvider.getParent(element);

 		int index= buildItemChain(parent);

 		BreadcrumbItem item;
 		if (index < fBreadcrumbItems.size()) {
 			item= fBreadcrumbItems.get(index);
 			if (item.getData() != null)
 				unmapElement(item.getData());
 		} else {
 			item= createItem();
 			fBreadcrumbItems.add(item);
 		}

 		if (equals(element, item.getData())) {
 			update(element, null);
 		} else {
 			item.setData(element);
 			item.refresh();
 		}
 		if (parent == null) {
 			//don't show the models root
 			item.setDetailsVisible(false);
 		}

 		mapElement(element, item);

 		return index + 1;
 	}

 	/**
 	 * Creates and returns a new instance of a breadcrumb item.
 	 *
 	 * @return new instance of a breadcrumb item
 	 */
 	private BreadcrumbItem createItem() {
 		BreadcrumbItem result= new BreadcrumbItem(this, fContainer);

 		result.setLabelProvider((ILabelProvider) getLabelProvider());
 		if (fToolTipLabelProvider != null) {
 			result.setToolTipLabelProvider(fToolTipLabelProvider);
 		} else {
 			result.setToolTipLabelProvider((ILabelProvider) getLabelProvider());
 		}
 		result.setContentProvider((ITreeContentProvider) getContentProvider());

 		return result;
 	}

 	/**
 	 * Update the size of the items such that all items are visible, if possible.
 	 *
 	 * @return <code>true</code> if any item has changed, <code>false</code> otherwise
 	 */
 	private boolean updateSize() {
 		int width= fContainer.getClientArea().width;

 		int currentWidth= getCurrentWidth();

 		boolean requiresLayout= false;

 		if (currentWidth > width) {
 			int index= 0;
 			while (currentWidth > width && index < fBreadcrumbItems.size() - 1) {
 				BreadcrumbItem viewer= fBreadcrumbItems.get(index);
 				if (viewer.isShowText()) {
 					viewer.setShowText(false);
 					currentWidth= getCurrentWidth();
 					requiresLayout= true;
 				}

 				index++;
 			}

 		} else if (currentWidth < width) {

 			int index= fBreadcrumbItems.size() - 1;
 			while (currentWidth < width && index >= 0) {

 				BreadcrumbItem viewer= fBreadcrumbItems.get(index);
 				if (!viewer.isShowText()) {
 					viewer.setShowText(true);
 					currentWidth= getCurrentWidth();
 					if (currentWidth > width) {
 						viewer.setShowText(false);
 						index= 0;
 					} else {
 						requiresLayout= true;
 					}
 				}

 				index--;
 			}
 		}

 		return requiresLayout;
 	}

 	/**
 	 * Returns the current width of all items in the list.
 	 *
 	 * @return the width of all items in the list
 	 */
 	private int getCurrentWidth() {
 		int result= 0;
 		for (int i= 0, size= fBreadcrumbItems.size(); i < size; i++) {
 			BreadcrumbItem viewer= fBreadcrumbItems.get(i);
 			result+= viewer.getWidth();
 		}

 		return result;
 	}

 	/**
 	 * Enables redrawing of the breadcrumb.
 	 */
 	private void enableRedraw() {
 		if (IS_GTK) //flickers on GTK
 			return;

 		fContainer.setRedraw(true);
 	}

 	/**
 	 * Disables redrawing of the breadcrumb.
 	 *
 	 * <p>
 	 * <strong>A call to this method must be followed by a call to {@link #enableRedraw()}</strong>
 	 * </p>
 	 */
 	private void disableRedraw() {
 		if (IS_GTK) //flickers on GTK
 			return;

 		fContainer.setRedraw(false);
 	}

 	/*
 	 * @see org.eclipse.jface.viewers.StructuredViewer#handleDispose(org.eclipse.swt.events.DisposeEvent)
 	 * @since 3.6.1
 	 */
 	@Override
 	protected void handleDispose(DisposeEvent event) {
 		if (fGradientBackground != null) {
 			fGradientBackground.dispose();
 			fGradientBackground= null;
 		}

 		if (fToolTipLabelProvider != null) {
 			fToolTipLabelProvider.dispose();
 			fToolTipLabelProvider= null;
 		}

 		if (fBreadcrumbItems != null) {
 			Iterator<BreadcrumbItem> iterator= fBreadcrumbItems.iterator();
 			while (iterator.hasNext()) {
 				BreadcrumbItem item= iterator.next();
 				item.dispose();
 			}
 		}

 		super.handleDispose(event);
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2008, 2011 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
	* Fabio Zadrozny - Bug 465666
	*******************************************************************************/
	package org.eclipse.jdt.internal.ui.javaeditor.breadcrumb;

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

	import org.eclipse.swt.SWT;
	import org.eclipse.swt.events.DisposeEvent;
	import org.eclipse.swt.events.MenuDetectEvent;
	import org.eclipse.swt.events.MenuDetectListener;
	import org.eclipse.swt.events.TraverseEvent;
	import org.eclipse.swt.events.TraverseListener;
	import org.eclipse.swt.graphics.Image;
	import org.eclipse.swt.layout.GridData;
	import org.eclipse.swt.layout.GridLayout;
	import org.eclipse.swt.widgets.Composite;
	import org.eclipse.swt.widgets.Control;
	import org.eclipse.swt.widgets.Event;
	import org.eclipse.swt.widgets.Listener;
	import org.eclipse.swt.widgets.Shell;
	import org.eclipse.swt.widgets.Widget;

	import org.eclipse.core.runtime.Assert;
	import org.eclipse.core.runtime.ListenerList;

	import org.eclipse.jface.viewers.CellLabelProvider;
	import org.eclipse.jface.viewers.DoubleClickEvent;
	import org.eclipse.jface.viewers.IContentProvider;
	import org.eclipse.jface.viewers.ILabelProvider;
	import org.eclipse.jface.viewers.ISelectionProvider;
	import org.eclipse.jface.viewers.ITreeContentProvider;
	import org.eclipse.jface.viewers.OpenEvent;
	import org.eclipse.jface.viewers.SelectionChangedEvent;
	import org.eclipse.jface.viewers.StructuredSelection;
	import org.eclipse.jface.viewers.StructuredViewer;
	import org.eclipse.jface.viewers.TreeViewer;
	import org.eclipse.jface.viewers.ViewerCell;


	/**
	* A breadcrumb viewer shows a the parent chain of its input element in a list. Each breadcrumb item
	* of that list can be expanded and a sibling of the element presented by the breadcrumb item can be
	* selected.
	* <p>
	* Content providers for breadcrumb viewers must implement the <code>ITreeContentProvider</code>
	* interface.
	* </p>
	* <p>
	* Label providers for breadcrumb viewers must implement the <code>ILabelProvider</code> interface.
	* </p>
	*
	* @since 3.4
	*/
	public abstract class BreadcrumbViewer extends StructuredViewer {

	private static final boolean IS_GTK= "gtk".equals(SWT.getPlatform()); //$NON-NLS-1$

	private final Composite fContainer;
	private final ArrayList<BreadcrumbItem> fBreadcrumbItems;
	private final ListenerList<MenuDetectListener> fMenuListeners;

	private Image fGradientBackground;
	private BreadcrumbItem fSelectedItem;
	private ILabelProvider fToolTipLabelProvider;


	/**
	* Create a new <code>BreadcrumbViewer</code>.
	* <p>
	* Style is one of:
	* <ul>
	* <li>SWT.NONE</li>
	* <li>SWT.VERTICAL</li>
	* <li>SWT.HORIZONTAL</li>
	* </ul>
	*
	* @param parent the container for the viewer
	* @param style the style flag used for this viewer
	*/
	public BreadcrumbViewer(Composite parent, int style) {
	fBreadcrumbItems= new ArrayList<>();
	fMenuListeners= new ListenerList<>();

	fContainer= new Composite(parent, SWT.NONE);
	GridData layoutData= new GridData(SWT.FILL, SWT.TOP, true, false);
	fContainer.setLayoutData(layoutData);
	fContainer.addTraverseListener(new TraverseListener() {
	@Override
	public void keyTraversed(TraverseEvent e) {
	e.doit= true;
	}
	});
	fContainer.setBackgroundMode(SWT.INHERIT_DEFAULT);
	fContainer.setData("org.eclipse.e4.ui.css.id", "BreadcrumbComposite"); //$NON-NLS-1$ //$NON-NLS-2$

	hookControl(fContainer);

	int columns= 1000;
	if ((SWT.VERTICAL & style) != 0) {
	columns= 1;
	}

	GridLayout gridLayout= new GridLayout(columns, false);
	gridLayout.marginWidth= 0;
	gridLayout.marginHeight= 0;
	gridLayout.verticalSpacing= 0;
	gridLayout.horizontalSpacing= 0;
	fContainer.setLayout(gridLayout);

	fContainer.addListener(SWT.Resize, new Listener() {
	@Override
	public void handleEvent(Event event) {
	refresh();
	}
	});
	}

	/**
	* Configure the given drop down viewer. The given input is used for the viewers input. Clients
	* must at least set the label and the content provider for the viewer.
	*
	* @param viewer the viewer to configure
	* @param input the input for the viewer
	*/
	protected abstract void configureDropDownViewer(TreeViewer viewer, Object input);

	/**
	* The tool tip to use for the tool tip labels. <code>null</code> if the viewers label provider
	* should be used.
	*
	* @param toolTipLabelProvider the label provider for the tool tips or <code>null</code>
	*/
	public void setToolTipLabelProvider(ILabelProvider toolTipLabelProvider) {
	fToolTipLabelProvider= toolTipLabelProvider;
	}

	/*
	* @see org.eclipse.jface.viewers.Viewer#getControl()
	*/
	@Override
	public Control getControl() {
	return fContainer;
	}

	/*
	* @see org.eclipse.jface.viewers.StructuredViewer#getRoot()
	*/
	@Override
	protected Object getRoot() {
	if (fBreadcrumbItems.isEmpty())
	return null;

	return fBreadcrumbItems.get(0).getData();
	}

	/*
	* @see org.eclipse.jface.viewers.StructuredViewer#reveal(java.lang.Object)
	*/
	@Override
	public void reveal(Object element) {
	//all elements are always visible
	}

	/**
	* Transfers the keyboard focus into the viewer.
	*/
	public void setFocus() {
	fContainer.setFocus();

	if (fSelectedItem != null) {
	fSelectedItem.setFocus(true);
	} else {
	if (fBreadcrumbItems.size() == 0)
	return;

	BreadcrumbItem item= fBreadcrumbItems.get(fBreadcrumbItems.size() - 1);
	if (item.getData() == null) {
	if (fBreadcrumbItems.size() < 2)
	return;

	item= fBreadcrumbItems.get(fBreadcrumbItems.size() - 2);
	}
	item.setFocus(true);
	}
	}

	/**
	* @return true if any of the items in the viewer is expanded
	*/
	public boolean isDropDownOpen() {
	for (int i= 0, size= fBreadcrumbItems.size(); i < size; i++) {
	BreadcrumbItem item= fBreadcrumbItems.get(i);
	if (item.isMenuShown())
	return true;
	}

	return false;
	}

	/**
	* The shell used for the shown drop down or <code>null</code>
	* if no drop down is shown at the moment.
	*
	* @return the drop downs shell or <code>null</code>
	*/
	public Shell getDropDownShell() {
	for (int i= 0, size= fBreadcrumbItems.size(); i < size; i++) {
	BreadcrumbItem item= fBreadcrumbItems.get(i);
	if (item.isMenuShown())
	return item.getDropDownShell();
	}

	return null;
	}

	/**
	* Returns the selection provider which provides the selection of the drop down currently opened
	* or <code>null</code> if no drop down is open at the moment.
	*
	* @return the selection provider of the open drop down or <code>null</code>
	*/
	public ISelectionProvider getDropDownSelectionProvider() {
	for (int i= 0, size= fBreadcrumbItems.size(); i < size; i++) {
	BreadcrumbItem item= fBreadcrumbItems.get(i);
	if (item.isMenuShown()) {
	return item.getDropDownSelectionProvider();
	}
	}

	return null;
	}

	/**
	* Add the given listener to the set of listeners which will be informed
	* when a context menu is requested for a breadcrumb item.
	*
	* @param listener the listener to add
	*/
	public void addMenuDetectListener(MenuDetectListener listener) {
	fMenuListeners.add(listener);
	}

	/**
	* Remove the given listener from the set of menu detect listeners.
	* Does nothing if the listener is not element of the set.
	*
	* @param listener the listener to remove
	*/
	public void removeMenuDetectListener(MenuDetectListener listener) {
	fMenuListeners.remove(listener);
	}

	/*
	* @see org.eclipse.jface.viewers.StructuredViewer#assertContentProviderType(org.eclipse.jface.viewers.IContentProvider)
	*/
	@Override
	protected void assertContentProviderType(IContentProvider provider) {
	super.assertContentProviderType(provider);
	Assert.isTrue(provider instanceof ITreeContentProvider);
	}

	/*
	* @see org.eclipse.jface.viewers.Viewer#inputChanged(java.lang.Object, java.lang.Object)
	*/
	@Override
	protected void inputChanged(Object fInput, Object oldInput) {
	if (fContainer.isDisposed())
	return;

	disableRedraw();
	try {
	if (fBreadcrumbItems.size() > 0) {
	BreadcrumbItem last= fBreadcrumbItems.get(fBreadcrumbItems.size() - 1);
	last.setIsLastItem(false);
	}

	int lastIndex= buildItemChain(fInput);

	if (lastIndex > 0) {
	BreadcrumbItem last= fBreadcrumbItems.get(lastIndex - 1);
	last.setIsLastItem(true);
	}

	while (lastIndex < fBreadcrumbItems.size()) {
	BreadcrumbItem item= fBreadcrumbItems.remove(fBreadcrumbItems.size() - 1);
	if (item == fSelectedItem) {
	selectItem(null);
	}
	if (item.getData() != null)
	unmapElement(item.getData());
	item.dispose();
	}

	updateSize();
	fContainer.layout(true, true);
	} finally {
	enableRedraw();
	}
	}

	/*
	* @see org.eclipse.jface.viewers.StructuredViewer#doFindInputItem(java.lang.Object)
	*/
	@Override
	protected Widget doFindInputItem(Object element) {
	if (element == null)
	return null;

	if (element == getInput() \|\| element.equals(getInput()))
	return doFindItem(element);

	return null;
	}

	/*
	* @see org.eclipse.jface.viewers.StructuredViewer#doFindItem(java.lang.Object)
	*/
	@Override
	protected Widget doFindItem(Object element) {
	if (element == null)
	return null;

	for (int i= 0, size= fBreadcrumbItems.size(); i < size; i++) {
	BreadcrumbItem item= fBreadcrumbItems.get(i);
	if (item.getData() == element \|\| element.equals(item.getData()))
	return item;
	}

	return null;
	}

	/*
	* @see org.eclipse.jface.viewers.StructuredViewer#doUpdateItem(org.eclipse.swt.widgets.Widget, java.lang.Object, boolean)
	*/
	@Override
	protected void doUpdateItem(Widget widget, Object element, boolean fullMap) {
	if (widget instanceof BreadcrumbItem) {
	final BreadcrumbItem item= (BreadcrumbItem) widget;

	// remember element we are showing
	if (fullMap) {
	associate(element, item);
	} else {
	Object data= item.getData();
	if (data != null) {
	unmapElement(data, item);
	}
	item.setData(element);
	mapElement(element, item);
	}

	BreadcrumbViewerRow row= new BreadcrumbViewerRow(this, item);
	ViewerCell cell= row.getCell(0);

	((CellLabelProvider) getLabelProvider()).update(cell);

	item.refreshArrow();

	if (fToolTipLabelProvider != null) {
	item.setToolTip(fToolTipLabelProvider.getText(item.getData()));
	} else {
	item.setToolTip(cell.getText());
	}
	}
	}

	/*
	* @see org.eclipse.jface.viewers.StructuredViewer#getSelectionFromWidget()
	*/
	@Override
	protected List getSelectionFromWidget() {
	if (fSelectedItem == null)
	return Collections.EMPTY_LIST;

	if (fSelectedItem.getData() == null)
	return Collections.EMPTY_LIST;

	ArrayList<Object> result= new ArrayList<>();
	result.add(fSelectedItem.getData());
	return result;
	}

	/*
	* @see org.eclipse.jface.viewers.StructuredViewer#internalRefresh(java.lang.Object)
	*/
	@Override
	protected void internalRefresh(Object element) {

	disableRedraw();
	try {
	BreadcrumbItem item= (BreadcrumbItem) doFindItem(element);
	if (item == null) {
	for (int i= 0, size= fBreadcrumbItems.size(); i < size; i++) {
	BreadcrumbItem item1= fBreadcrumbItems.get(i);
	item1.refresh();
	}
	} else {
	item.refresh();
	}
	if (updateSize())
	fContainer.layout(true, true);
	} finally {
	enableRedraw();
	}
	}

	/*
	* @see org.eclipse.jface.viewers.StructuredViewer#setSelectionToWidget(java.util.List, boolean)
	*/
	@Override
	protected void setSelectionToWidget(List l, boolean reveal) {
	BreadcrumbItem focusItem= null;

	for (int i= 0, size= fBreadcrumbItems.size(); i < size; i++) {
	BreadcrumbItem item= fBreadcrumbItems.get(i);
	if (item.hasFocus())
	focusItem= item;

	item.setSelected(false);
	}

	if (l == null)
	return;

	for (Iterator<?> iterator= l.iterator(); iterator.hasNext();) {
	Object element= iterator.next();
	BreadcrumbItem item= (BreadcrumbItem) doFindItem(element);
	if (item != null) {
	item.setSelected(true);
	fSelectedItem= item;
	if (item == focusItem) {
	item.setFocus(true);
	}
	}
	}
	}

	/**
	* Set a single selection to the given item. <code>null</code> to deselect all.
	*
	* @param item the item to select or <code>null</code>
	*/
	void selectItem(BreadcrumbItem item) {
	if (fSelectedItem != null)
	fSelectedItem.setSelected(false);

	fSelectedItem= item;
	setSelectionToWidget(getSelection(), false);

	if (item != null) {
	setFocus();
	} else {
	for (int i= 0, size= fBreadcrumbItems.size(); i < size; i++) {
	BreadcrumbItem listItem= fBreadcrumbItems.get(i);
	listItem.setFocus(false);
	}
	}

	fireSelectionChanged(new SelectionChangedEvent(this, getSelection()));
	}

	/**
	* Returns the item count.
	*
	* @return number of items shown in the viewer
	*/
	int getItemCount() {
	return fBreadcrumbItems.size();
	}

	/**
	* Returns the item for the given item index.
	*
	* @param index the index of the item
	* @return the item ad the given <code>index</code>
	*/
	BreadcrumbItem getItem(int index) {
	return fBreadcrumbItems.get(index);
	}

	/**
	* Returns the index of the given item.
	*
	* @param item the item to search
	* @return the index of the item or -1 if not found
	*/
	int getIndexOfItem(BreadcrumbItem item) {
	for (int i= 0, size= fBreadcrumbItems.size(); i < size; i++) {
	BreadcrumbItem pItem= fBreadcrumbItems.get(i);
	if (pItem == item)
	return i;
	}

	return -1;
	}

	/**
	* Notifies all double click listeners.
	*/
	void fireDoubleClick() {
	fireDoubleClick(new DoubleClickEvent(this, getSelection()));
	}

	/**
	* Notifies all open listeners.
	*/
	void fireOpen() {
	fireOpen(new OpenEvent(this, getSelection()));
	}

	/**
	* The given element was selected from a drop down menu.
	*
	* @param element the selected element
	*/
	void fireMenuSelection(Object element) {
	fireOpen(new OpenEvent(this, new StructuredSelection(element)));
	}

	/**
	* A context menu has been requested for the selected breadcrumb item.
	*
	* @param event the event issued the menu detection
	*/
	void fireMenuDetect(MenuDetectEvent event) {
	for (MenuDetectListener listener : fMenuListeners) {
	listener.menuDetected(event);
	}
	}

	/**
	* Set selection to the next or previous element if possible.
	*
	* @param next <code>true</code> if the next element should be selected, otherwise the previous
	* one will be selected
	*/
	void doTraverse(boolean next) {
	if (fSelectedItem == null)
	return;

	int index= fBreadcrumbItems.indexOf(fSelectedItem);
	if (next) {
	if (index == fBreadcrumbItems.size() - 1) {
	BreadcrumbItem current= fBreadcrumbItems.get(index);

	ITreeContentProvider contentProvider= (ITreeContentProvider) getContentProvider();
	if (!contentProvider.hasChildren(current.getData()))
	return;

	current.openDropDownMenu();
	current.getDropDownShell().setFocus();
	} else {
	BreadcrumbItem nextItem= fBreadcrumbItems.get(index + 1);
	selectItem(nextItem);
	}
	} else {
	if (index == 1) {
	BreadcrumbItem root= fBreadcrumbItems.get(0);
	root.openDropDownMenu();
	root.getDropDownShell().setFocus();
	} else {
	selectItem(fBreadcrumbItems.get(index - 1));
	}
	}
	}

	/**
	* Generates the parent chain of the given element.
	*
	* @param element element to build the parent chain for
	* @return the first index of an item in fBreadcrumbItems which is not part of the chain
	*/
	private int buildItemChain(Object element) {
	if (element == null)
	return 0;

	ITreeContentProvider contentProvider= (ITreeContentProvider) getContentProvider();
	Object parent= contentProvider.getParent(element);

	int index= buildItemChain(parent);

	BreadcrumbItem item;
	if (index < fBreadcrumbItems.size()) {
	item= fBreadcrumbItems.get(index);
	if (item.getData() != null)
	unmapElement(item.getData());
	} else {
	item= createItem();
	fBreadcrumbItems.add(item);
	}

	if (equals(element, item.getData())) {
	update(element, null);
	} else {
	item.setData(element);
	item.refresh();
	}
	if (parent == null) {
	//don't show the models root
	item.setDetailsVisible(false);
	}

	mapElement(element, item);

	return index + 1;
	}

	/**
	* Creates and returns a new instance of a breadcrumb item.
	*
	* @return new instance of a breadcrumb item
	*/
	private BreadcrumbItem createItem() {
	BreadcrumbItem result= new BreadcrumbItem(this, fContainer);

	result.setLabelProvider((ILabelProvider) getLabelProvider());
	if (fToolTipLabelProvider != null) {
	result.setToolTipLabelProvider(fToolTipLabelProvider);
	} else {
	result.setToolTipLabelProvider((ILabelProvider) getLabelProvider());
	}
	result.setContentProvider((ITreeContentProvider) getContentProvider());

	return result;
	}

	/**
	* Update the size of the items such that all items are visible, if possible.
	*
	* @return <code>true</code> if any item has changed, <code>false</code> otherwise
	*/
	private boolean updateSize() {
	int width= fContainer.getClientArea().width;

	int currentWidth= getCurrentWidth();

	boolean requiresLayout= false;

	if (currentWidth > width) {
	int index= 0;
	while (currentWidth > width && index < fBreadcrumbItems.size() - 1) {
	BreadcrumbItem viewer= fBreadcrumbItems.get(index);
	if (viewer.isShowText()) {
	viewer.setShowText(false);
	currentWidth= getCurrentWidth();
	requiresLayout= true;
	}

	index++;
	}

	} else if (currentWidth < width) {

	int index= fBreadcrumbItems.size() - 1;
	while (currentWidth < width && index >= 0) {

	BreadcrumbItem viewer= fBreadcrumbItems.get(index);
	if (!viewer.isShowText()) {
	viewer.setShowText(true);
	currentWidth= getCurrentWidth();
	if (currentWidth > width) {
	viewer.setShowText(false);
	index= 0;
	} else {
	requiresLayout= true;
	}
	}

	index--;
	}
	}

	return requiresLayout;
	}

	/**
	* Returns the current width of all items in the list.
	*
	* @return the width of all items in the list
	*/
	private int getCurrentWidth() {
	int result= 0;
	for (int i= 0, size= fBreadcrumbItems.size(); i < size; i++) {
	BreadcrumbItem viewer= fBreadcrumbItems.get(i);
	result+= viewer.getWidth();
	}

	return result;
	}

	/**
	* Enables redrawing of the breadcrumb.
	*/
	private void enableRedraw() {
	if (IS_GTK) //flickers on GTK
	return;

	fContainer.setRedraw(true);
	}

	/**
	* Disables redrawing of the breadcrumb.
	*
	* <p>
	* <strong>A call to this method must be followed by a call to {@link #enableRedraw()}</strong>
	* </p>
	*/
	private void disableRedraw() {
	if (IS_GTK) //flickers on GTK
	return;

	fContainer.setRedraw(false);
	}

	/*
	* @see org.eclipse.jface.viewers.StructuredViewer#handleDispose(org.eclipse.swt.events.DisposeEvent)
	* @since 3.6.1
	*/
	@Override
	protected void handleDispose(DisposeEvent event) {
	if (fGradientBackground != null) {
	fGradientBackground.dispose();
	fGradientBackground= null;
	}

	if (fToolTipLabelProvider != null) {
	fToolTipLabelProvider.dispose();
	fToolTipLabelProvider= null;
	}

	if (fBreadcrumbItems != null) {
	Iterator<BreadcrumbItem> iterator= fBreadcrumbItems.iterator();
	while (iterator.hasNext()) {
	BreadcrumbItem item= iterator.next();
	item.dispose();
	}
	}

	super.handleDispose(event);
	}
	}