core/plugins/org.eclipse.dltk.ui/src/org/eclipse/dltk/internal/ui/navigator/ProjectFragmentProvider.java - dltk/org.eclipse.dltk.core - Git at Google

 /*******************************************************************************
  * Copyright (c) 2000, 2018 IBM Corporation and others.
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0 which is available at
  * http://www.eclipse.org/legal/epl-2.0.
  *
  * SPDX-License-Identifier: EPL-2.0
  *
  *******************************************************************************/
 package org.eclipse.dltk.internal.ui.navigator;

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

 import org.eclipse.core.resources.IFolder;
 import org.eclipse.core.resources.IProject;
 import org.eclipse.core.resources.IResource;
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.dltk.core.DLTKCore;
 import org.eclipse.dltk.core.ElementChangedEvent;
 import org.eclipse.dltk.core.IModelElement;
 import org.eclipse.dltk.core.IModelElementDelta;
 import org.eclipse.dltk.core.IProjectFragment;
 import org.eclipse.dltk.core.IScriptFolder;
 import org.eclipse.dltk.core.IScriptProject;
 import org.eclipse.dltk.core.ModelException;
 import org.eclipse.dltk.ui.DLTKUIPlugin;
 import org.eclipse.dltk.ui.PreferenceConstants;
 import org.eclipse.jface.preference.IPreferenceStore;
 import org.eclipse.jface.util.IPropertyChangeListener;
 import org.eclipse.jface.util.PropertyChangeEvent;
 import org.eclipse.jface.viewers.TreeViewer;
 import org.eclipse.jface.viewers.Viewer;
 import org.eclipse.swt.widgets.Control;
 import org.eclipse.swt.widgets.Display;

 /**
  * Content provider which provides package fragments for hierarchical Package
  * Explorer layout.
  *
  */
 public class ProjectFragmentProvider implements IPropertyChangeListener {

 	private TreeViewer fViewer;
 	private boolean fFoldPackages;
 	private IPreferenceStore fStore;

 	public ProjectFragmentProvider(IPreferenceStore store) {
 		fStore = store;
 		fFoldPackages = arePackagesFoldedInHierarchicalLayout();
 		fStore.addPropertyChangeListener(this);
 	}

 	public Object[] getChildren(Object parentElement) {
 		try {
 			if (parentElement instanceof IFolder) {
 				IResource[] resources = ((IFolder) parentElement).members();
 				return filter(getFolders(resources)).toArray();
 			} else if (parentElement instanceof IModelElement) {
 				IModelElement iModelElement = (IModelElement) parentElement;
 				int type = iModelElement.getElementType();

 				switch (type) {
 				case IModelElement.SCRIPT_PROJECT: {
 					IScriptProject project = (IScriptProject) iModelElement;

 					IProjectFragment root = project
 							.findProjectFragment(project.getPath());
 					if (root != null) {
 						List<IModelElement> children = getTopLevelChildren(
 								root);
 						return filter(children).toArray();
 					}
 					break;
 				}
 				case IModelElement.PROJECT_FRAGMENT: {
 					IProjectFragment root = (IProjectFragment) parentElement;
 					if (root.exists()) {
 						return filter(getTopLevelChildren(root)).toArray();
 					}
 					break;
 				}
 				case IModelElement.SCRIPT_FOLDER: {
 					IScriptFolder scriptFolder = (IScriptFolder) parentElement;
 					if (!scriptFolder.isRootFolder()) {
 						IProjectFragment root = (IProjectFragment) scriptFolder
 								.getParent();
 						List<IScriptFolder> children = getPackageChildren(root,
 								scriptFolder);
 						return filter(children).toArray();
 					}
 					break;
 				}
 				default:
 					// do nothing
 				}
 			}
 		} catch (CoreException e) {
 			DLTKUIPlugin.log(e);
 		}
 		return new Object[0];
 	}

 	private List filter(List children) throws ModelException {
 		if (fFoldPackages) {
 			int size = children.size();
 			for (int i = 0; i < size; i++) {
 				Object curr = children.get(i);
 				if (curr instanceof IScriptFolder) {
 					IScriptFolder fragment = (IScriptFolder) curr;
 					if (!fragment.isRootFolder() && isEmpty(fragment)) {
 						IScriptFolder collapsed = getCollapsed(fragment);
 						if (collapsed != null) {
 							children.set(i, collapsed); // replace with
 														// collapsed
 						}
 					}
 				}
 			}
 		}
 		return children;
 	}

 	private IScriptFolder getCollapsed(IScriptFolder pack)
 			throws ModelException {
 		IModelElement[] children = ((IProjectFragment) pack.getParent())
 				.getChildren();
 		IScriptFolder child = getSinglePackageChild(pack, children);
 		while (child != null && isEmpty(child)) {
 			IScriptFolder collapsed = getSinglePackageChild(child, children);
 			if (collapsed == null) {
 				return child;
 			}
 			child = collapsed;
 		}
 		return child;
 	}

 	private boolean isEmpty(IScriptFolder fragment) throws ModelException {
 		return !fragment.containsScriptResources()
 				&& fragment.getForeignResources().length == 0;
 	}

 	private static IScriptFolder getSinglePackageChild(IScriptFolder fragment,
 			IModelElement[] children) {
 		String prefix = fragment.getElementName()
 				+ IScriptFolder.PACKAGE_DELIMITER;
 		int prefixLen = prefix.length();
 		IScriptFolder found = null;
 		for (int i = 0; i < children.length; i++) {
 			IModelElement element = children[i];
 			String name = element.getElementName();
 			if (name.startsWith(prefix) && name.length() > prefixLen
 					&& name.indexOf(IScriptFolder.PACKAGE_DELIMITER,
 							prefixLen) == -1) {
 				if (found == null) {
 					found = (IScriptFolder) element;
 				} else {
 					return null;
 				}
 			}
 		}
 		return found;
 	}

 	private static List<IScriptFolder> getPackageChildren(
 			IProjectFragment parent, IScriptFolder fragment)
 			throws ModelException {
 		IModelElement[] children = parent.getChildren();
 		ArrayList<IScriptFolder> list = new ArrayList<>(children.length);
 		String prefix = fragment.getElementName()
 				+ IScriptFolder.PACKAGE_DELIMITER;
 		int prefixLen = prefix.length();
 		for (int i = 0; i < children.length; i++) {
 			IModelElement element = children[i];
 			if (element instanceof IScriptFolder) { // see bug 134256
 				String name = element.getElementName();
 				if (name.startsWith(prefix) && name.length() > prefixLen
 						&& name.indexOf(IScriptFolder.PACKAGE_DELIMETER_STR,
 								prefixLen) == -1) {
 					list.add((IScriptFolder) element);
 				}
 			}
 		}
 		return list;
 	}

 	private static List<IModelElement> getTopLevelChildren(
 			IProjectFragment root) throws ModelException {
 		IModelElement[] elements = root.getChildren();
 		ArrayList<IModelElement> topLevelElements = new ArrayList<>(
 				elements.length);
 		for (int i = 0; i < elements.length; i++) {
 			IModelElement iModelElement = elements[i];
 			// if the name of the ScriptFolder is the top level package it will
 			// contain no "." separators
 			if (iModelElement instanceof IScriptFolder
 					&& iModelElement.getElementName()
 							.indexOf(IScriptFolder.PACKAGE_DELIMITER) == -1) {
 				IScriptFolder folder = (IScriptFolder) iModelElement;
 				if (!folder.isRootFolder()) {
 					topLevelElements.add(iModelElement);
 				} else {
 					IModelElement[] children = folder.getChildren();
 					for (int j = 0; j < children.length; j++) {
 						topLevelElements.add(children[j]);
 					}
 				}
 			}
 		}
 		return topLevelElements;
 	}

 	private List<IFolder> getFolders(IResource[] resources)
 			throws ModelException {
 		List<IFolder> list = new ArrayList<>(resources.length);
 		for (int i = 0; i < resources.length; i++) {
 			IResource resource = resources[i];
 			if (resource instanceof IFolder) {
 				IFolder folder = (IFolder) resource;
 				// IModelElement element= DLTKCore.create(folder);
 				// if (element instanceof IScriptFolder) {
 				IProject project = folder.getProject();
 				IScriptProject scriptProject = DLTKCore.create(project);
 				if (scriptProject != null) {
 					if (scriptProject.isOnBuildpath(folder))
 						list.add(folder);
 				}
 				// }
 			}
 		}
 		return list;
 	}

 	public Object getParent(Object element) {

 		if (element instanceof IScriptFolder) {
 			IScriptFolder frag = (IScriptFolder) element;
 			// @Changed: a fix, before: if(frag.exists() && isEmpty(frag))

 			return filterParent(getActualParent(frag));
 		}
 		return null;
 	}

 	private Object getActualParent(IScriptFolder fragment) {
 		try {

 			if (fragment.exists()) {
 				IModelElement parent = fragment.getParent();

 				if ((parent instanceof IProjectFragment) && parent.exists()) {
 					IProjectFragment root = (IProjectFragment) parent;
 					if (root.isArchive()) {
 						return findNextLevelParentByElementName(fragment);
 					}

 					IResource resource = fragment.getUnderlyingResource();
 					if ((resource != null) && (resource instanceof IFolder)) {
 						IFolder folder = (IFolder) resource;
 						IResource res = folder.getParent();

 						IModelElement el = DLTKCore.create(res);
 						if (el != null) {
 							return el;
 						}
 						return res;
 					}
 					return parent;
 				}
 			}

 		} catch (ModelException e) {
 			DLTKUIPlugin.log(e);
 		}
 		return null;
 	}

 	private Object filterParent(Object parent) {
 		if (fFoldPackages && (parent != null)) {
 			try {
 				if (parent instanceof IScriptFolder) {
 					IScriptFolder fragment = (IScriptFolder) parent;
 					if (isEmpty(fragment) && hasSingleChild(fragment)) {
 						return filterParent(getActualParent(fragment));
 					}
 				}
 			} catch (ModelException e) {
 				DLTKUIPlugin.log(e);
 			}
 		}
 		return parent;
 	}

 	private boolean hasSingleChild(IScriptFolder fragment) {
 		return getChildren(fragment).length == 1;
 	}

 	private Object findNextLevelParentByElementName(IScriptFolder child) {
 		String name = child.getElementName();

 		int index = name.lastIndexOf(IScriptFolder.PACKAGE_DELIMITER);
 		if (index != -1) {
 			String realParentName = name.substring(0, index);
 			IScriptFolder element = ((IProjectFragment) child.getParent())
 					.getScriptFolder(realParentName);
 			if (element.exists()) {
 				return element;
 			}
 		}
 		return child.getParent();
 	}

 	/*
 	 * @see org.eclipse.jface.viewers.ITreeContentProvider#hasChildren(Object)
 	 */
 	public boolean hasChildren(Object element) {

 		if (element instanceof IScriptFolder) {
 			IScriptFolder fragment = (IScriptFolder) element;
 			if (fragment.isRootFolder())
 				return false;
 		}
 		return getChildren(element).length > 0;
 	}

 	/*
 	 * @see
 	 * org.eclipse.jface.viewers.IStructuredContentProvider#getElements(Object)
 	 */
 	public Object[] getElements(Object inputElement) {
 		return getChildren(inputElement);
 	}

 	/*
 	 * @see org.eclipse.jface.viewers.IContentProvider#dispose()
 	 */
 	public void dispose() {
 		fStore.removePropertyChangeListener(this);
 	}

 	/**
 	 * Called when the view is closed and opened.
 	 *
 	 * @see org.eclipse.jface.viewers.IContentProvider#inputChanged(Viewer,
 	 *      Object, Object)
 	 */
 	public void inputChanged(Viewer viewer, Object oldInput, Object newInput) {
 		fViewer = (TreeViewer) viewer;
 	}

 	public void elementChanged(ElementChangedEvent event) {
 		processDelta(event.getDelta());
 	}

 	public void processDelta(IModelElementDelta delta) {

 		int kind = delta.getKind();
 		final IModelElement element = delta.getElement();

 		if (element instanceof IScriptFolder) {

 			if (kind == IModelElementDelta.REMOVED) {

 				postRunnable(() -> {
 					Control ctrl = fViewer.getControl();
 					if (ctrl != null && !ctrl.isDisposed()) {
 						if (!fFoldPackages)
 							fViewer.remove(element);
 						else
 							refreshGrandParent(element);
 					}
 				});
 				return;

 			} else if (kind == IModelElementDelta.ADDED) {

 				final Object parent = getParent(element);
 				if (parent != null) {
 					postRunnable(() -> {
 						Control ctrl = fViewer.getControl();
 						if (ctrl != null && !ctrl.isDisposed()) {
 							if (!fFoldPackages)
 								fViewer.add(parent, element);
 							else
 								refreshGrandParent(element);
 						}
 					});
 				}
 				return;
 			}
 		}
 	}

 	// XXX: needs to be revisited - might be a performance issue
 	private void refreshGrandParent(final IModelElement element) {
 		if (element instanceof IScriptFolder) {
 			Object gp = getGrandParent((IScriptFolder) element);
 			if (gp instanceof IModelElement) {
 				IModelElement el = (IModelElement) gp;
 				if (el.exists())
 					fViewer.refresh(gp);
 			} else if (gp instanceof IFolder) {
 				IFolder folder = (IFolder) gp;
 				if (folder.exists())
 					fViewer.refresh(folder);
 			}
 		}
 	}

 	private Object getGrandParent(IScriptFolder element) {

 		Object parent = findNextLevelParentByElementName(element);
 		if (parent instanceof IProjectFragment) {
 			IProjectFragment root = (IProjectFragment) parent;
 			if (isRootProject(root)) {
 				return root.getScriptProject();
 			}
 			return root;
 		}

 		Object grandParent = getParent(parent);
 		if (grandParent == null) {
 			return parent;
 		}
 		return grandParent;
 	}

 	private boolean isRootProject(IProjectFragment root) {
 		if (IProjectFragment.DEFAULT_PACKAGE_ROOT.equals(root.getElementName()))
 			return true;
 		return false;
 	}

 	private void postRunnable(final Runnable r) {
 		Control ctrl = fViewer.getControl();
 		if (ctrl != null && !ctrl.isDisposed()) {

 			Display currentDisplay = Display.getCurrent();
 			if (currentDisplay != null
 					&& currentDisplay.equals(ctrl.getDisplay()))
 				ctrl.getDisplay().syncExec(r);
 			else
 				ctrl.getDisplay().asyncExec(r);
 		}
 	}

 	/*
 	 * @see
 	 * org.eclipse.jface.util.IPropertyChangeListener#propertyChange(org.eclipse
 	 * .jface.util.PropertyChangeEvent)
 	 */
 	@Override
 	public void propertyChange(PropertyChangeEvent event) {
 		if (arePackagesFoldedInHierarchicalLayout() != fFoldPackages) {
 			fFoldPackages = arePackagesFoldedInHierarchicalLayout();
 			if (fViewer != null && !fViewer.getControl().isDisposed()) {
 				fViewer.getControl().setRedraw(false);
 				Object[] expandedObjects = fViewer.getExpandedElements();
 				fViewer.refresh();
 				fViewer.setExpandedElements(expandedObjects);
 				fViewer.getControl().setRedraw(true);
 			}
 		}
 	}

 	private boolean arePackagesFoldedInHierarchicalLayout() {
 		return fStore.getBoolean(
 				PreferenceConstants.APPEARANCE_FOLD_PACKAGES_IN_PACKAGE_EXPLORER);
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2000, 2018 IBM Corporation and others.
	* This program and the accompanying materials are made available under the
	* terms of the Eclipse Public License v. 2.0 which is available at
	* http://www.eclipse.org/legal/epl-2.0.
	*
	* SPDX-License-Identifier: EPL-2.0
	*
	*******************************************************************************/
	package org.eclipse.dltk.internal.ui.navigator;

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

	import org.eclipse.core.resources.IFolder;
	import org.eclipse.core.resources.IProject;
	import org.eclipse.core.resources.IResource;
	import org.eclipse.core.runtime.CoreException;
	import org.eclipse.dltk.core.DLTKCore;
	import org.eclipse.dltk.core.ElementChangedEvent;
	import org.eclipse.dltk.core.IModelElement;
	import org.eclipse.dltk.core.IModelElementDelta;
	import org.eclipse.dltk.core.IProjectFragment;
	import org.eclipse.dltk.core.IScriptFolder;
	import org.eclipse.dltk.core.IScriptProject;
	import org.eclipse.dltk.core.ModelException;
	import org.eclipse.dltk.ui.DLTKUIPlugin;
	import org.eclipse.dltk.ui.PreferenceConstants;
	import org.eclipse.jface.preference.IPreferenceStore;
	import org.eclipse.jface.util.IPropertyChangeListener;
	import org.eclipse.jface.util.PropertyChangeEvent;
	import org.eclipse.jface.viewers.TreeViewer;
	import org.eclipse.jface.viewers.Viewer;
	import org.eclipse.swt.widgets.Control;
	import org.eclipse.swt.widgets.Display;

	/**
	* Content provider which provides package fragments for hierarchical Package
	* Explorer layout.
	*
	*/
	public class ProjectFragmentProvider implements IPropertyChangeListener {

	private TreeViewer fViewer;
	private boolean fFoldPackages;
	private IPreferenceStore fStore;

	public ProjectFragmentProvider(IPreferenceStore store) {
	fStore = store;
	fFoldPackages = arePackagesFoldedInHierarchicalLayout();
	fStore.addPropertyChangeListener(this);
	}

	public Object[] getChildren(Object parentElement) {
	try {
	if (parentElement instanceof IFolder) {
	IResource[] resources = ((IFolder) parentElement).members();
	return filter(getFolders(resources)).toArray();
	} else if (parentElement instanceof IModelElement) {
	IModelElement iModelElement = (IModelElement) parentElement;
	int type = iModelElement.getElementType();

	switch (type) {
	case IModelElement.SCRIPT_PROJECT: {
	IScriptProject project = (IScriptProject) iModelElement;

	IProjectFragment root = project
	.findProjectFragment(project.getPath());
	if (root != null) {
	List<IModelElement> children = getTopLevelChildren(
	root);
	return filter(children).toArray();
	}
	break;
	}
	case IModelElement.PROJECT_FRAGMENT: {
	IProjectFragment root = (IProjectFragment) parentElement;
	if (root.exists()) {
	return filter(getTopLevelChildren(root)).toArray();
	}
	break;
	}
	case IModelElement.SCRIPT_FOLDER: {
	IScriptFolder scriptFolder = (IScriptFolder) parentElement;
	if (!scriptFolder.isRootFolder()) {
	IProjectFragment root = (IProjectFragment) scriptFolder
	.getParent();
	List<IScriptFolder> children = getPackageChildren(root,
	scriptFolder);
	return filter(children).toArray();
	}
	break;
	}
	default:
	// do nothing
	}
	}
	} catch (CoreException e) {
	DLTKUIPlugin.log(e);
	}
	return new Object[0];
	}

	private List filter(List children) throws ModelException {
	if (fFoldPackages) {
	int size = children.size();
	for (int i = 0; i < size; i++) {
	Object curr = children.get(i);
	if (curr instanceof IScriptFolder) {
	IScriptFolder fragment = (IScriptFolder) curr;
	if (!fragment.isRootFolder() && isEmpty(fragment)) {
	IScriptFolder collapsed = getCollapsed(fragment);
	if (collapsed != null) {
	children.set(i, collapsed); // replace with
	// collapsed
	}
	}
	}
	}
	}
	return children;
	}

	private IScriptFolder getCollapsed(IScriptFolder pack)
	throws ModelException {
	IModelElement[] children = ((IProjectFragment) pack.getParent())
	.getChildren();
	IScriptFolder child = getSinglePackageChild(pack, children);
	while (child != null && isEmpty(child)) {
	IScriptFolder collapsed = getSinglePackageChild(child, children);
	if (collapsed == null) {
	return child;
	}
	child = collapsed;
	}
	return child;
	}

	private boolean isEmpty(IScriptFolder fragment) throws ModelException {
	return !fragment.containsScriptResources()
	&& fragment.getForeignResources().length == 0;
	}

	private static IScriptFolder getSinglePackageChild(IScriptFolder fragment,
	IModelElement[] children) {
	String prefix = fragment.getElementName()
	+ IScriptFolder.PACKAGE_DELIMITER;
	int prefixLen = prefix.length();
	IScriptFolder found = null;
	for (int i = 0; i < children.length; i++) {
	IModelElement element = children[i];
	String name = element.getElementName();
	if (name.startsWith(prefix) && name.length() > prefixLen
	&& name.indexOf(IScriptFolder.PACKAGE_DELIMITER,
	prefixLen) == -1) {
	if (found == null) {
	found = (IScriptFolder) element;
	} else {
	return null;
	}
	}
	}
	return found;
	}

	private static List<IScriptFolder> getPackageChildren(
	IProjectFragment parent, IScriptFolder fragment)
	throws ModelException {
	IModelElement[] children = parent.getChildren();
	ArrayList<IScriptFolder> list = new ArrayList<>(children.length);
	String prefix = fragment.getElementName()
	+ IScriptFolder.PACKAGE_DELIMITER;
	int prefixLen = prefix.length();
	for (int i = 0; i < children.length; i++) {
	IModelElement element = children[i];
	if (element instanceof IScriptFolder) { // see bug 134256
	String name = element.getElementName();
	if (name.startsWith(prefix) && name.length() > prefixLen
	&& name.indexOf(IScriptFolder.PACKAGE_DELIMETER_STR,
	prefixLen) == -1) {
	list.add((IScriptFolder) element);
	}
	}
	}
	return list;
	}

	private static List<IModelElement> getTopLevelChildren(
	IProjectFragment root) throws ModelException {
	IModelElement[] elements = root.getChildren();
	ArrayList<IModelElement> topLevelElements = new ArrayList<>(
	elements.length);
	for (int i = 0; i < elements.length; i++) {
	IModelElement iModelElement = elements[i];
	// if the name of the ScriptFolder is the top level package it will
	// contain no "." separators
	if (iModelElement instanceof IScriptFolder
	&& iModelElement.getElementName()
	.indexOf(IScriptFolder.PACKAGE_DELIMITER) == -1) {
	IScriptFolder folder = (IScriptFolder) iModelElement;
	if (!folder.isRootFolder()) {
	topLevelElements.add(iModelElement);
	} else {
	IModelElement[] children = folder.getChildren();
	for (int j = 0; j < children.length; j++) {
	topLevelElements.add(children[j]);
	}
	}
	}
	}
	return topLevelElements;
	}

	private List<IFolder> getFolders(IResource[] resources)
	throws ModelException {
	List<IFolder> list = new ArrayList<>(resources.length);
	for (int i = 0; i < resources.length; i++) {
	IResource resource = resources[i];
	if (resource instanceof IFolder) {
	IFolder folder = (IFolder) resource;
	// IModelElement element= DLTKCore.create(folder);
	// if (element instanceof IScriptFolder) {
	IProject project = folder.getProject();
	IScriptProject scriptProject = DLTKCore.create(project);
	if (scriptProject != null) {
	if (scriptProject.isOnBuildpath(folder))
	list.add(folder);
	}
	// }
	}
	}
	return list;
	}

	public Object getParent(Object element) {

	if (element instanceof IScriptFolder) {
	IScriptFolder frag = (IScriptFolder) element;
	// @Changed: a fix, before: if(frag.exists() && isEmpty(frag))

	return filterParent(getActualParent(frag));
	}
	return null;
	}

	private Object getActualParent(IScriptFolder fragment) {
	try {

	if (fragment.exists()) {
	IModelElement parent = fragment.getParent();

	if ((parent instanceof IProjectFragment) && parent.exists()) {
	IProjectFragment root = (IProjectFragment) parent;
	if (root.isArchive()) {
	return findNextLevelParentByElementName(fragment);
	}

	IResource resource = fragment.getUnderlyingResource();
	if ((resource != null) && (resource instanceof IFolder)) {
	IFolder folder = (IFolder) resource;
	IResource res = folder.getParent();

	IModelElement el = DLTKCore.create(res);
	if (el != null) {
	return el;
	}
	return res;
	}
	return parent;
	}
	}

	} catch (ModelException e) {
	DLTKUIPlugin.log(e);
	}
	return null;
	}

	private Object filterParent(Object parent) {
	if (fFoldPackages && (parent != null)) {
	try {
	if (parent instanceof IScriptFolder) {
	IScriptFolder fragment = (IScriptFolder) parent;
	if (isEmpty(fragment) && hasSingleChild(fragment)) {
	return filterParent(getActualParent(fragment));
	}
	}
	} catch (ModelException e) {
	DLTKUIPlugin.log(e);
	}
	}
	return parent;
	}

	private boolean hasSingleChild(IScriptFolder fragment) {
	return getChildren(fragment).length == 1;
	}

	private Object findNextLevelParentByElementName(IScriptFolder child) {
	String name = child.getElementName();

	int index = name.lastIndexOf(IScriptFolder.PACKAGE_DELIMITER);
	if (index != -1) {
	String realParentName = name.substring(0, index);
	IScriptFolder element = ((IProjectFragment) child.getParent())
	.getScriptFolder(realParentName);
	if (element.exists()) {
	return element;
	}
	}
	return child.getParent();
	}

	/*
	* @see org.eclipse.jface.viewers.ITreeContentProvider#hasChildren(Object)
	*/
	public boolean hasChildren(Object element) {

	if (element instanceof IScriptFolder) {
	IScriptFolder fragment = (IScriptFolder) element;
	if (fragment.isRootFolder())
	return false;
	}
	return getChildren(element).length > 0;
	}

	/*
	* @see
	* org.eclipse.jface.viewers.IStructuredContentProvider#getElements(Object)
	*/
	public Object[] getElements(Object inputElement) {
	return getChildren(inputElement);
	}

	/*
	* @see org.eclipse.jface.viewers.IContentProvider#dispose()
	*/
	public void dispose() {
	fStore.removePropertyChangeListener(this);
	}

	/**
	* Called when the view is closed and opened.
	*
	* @see org.eclipse.jface.viewers.IContentProvider#inputChanged(Viewer,
	* Object, Object)
	*/
	public void inputChanged(Viewer viewer, Object oldInput, Object newInput) {
	fViewer = (TreeViewer) viewer;
	}

	public void elementChanged(ElementChangedEvent event) {
	processDelta(event.getDelta());
	}

	public void processDelta(IModelElementDelta delta) {

	int kind = delta.getKind();
	final IModelElement element = delta.getElement();

	if (element instanceof IScriptFolder) {

	if (kind == IModelElementDelta.REMOVED) {

	postRunnable(() -> {
	Control ctrl = fViewer.getControl();
	if (ctrl != null && !ctrl.isDisposed()) {
	if (!fFoldPackages)
	fViewer.remove(element);
	else
	refreshGrandParent(element);
	}
	});
	return;

	} else if (kind == IModelElementDelta.ADDED) {

	final Object parent = getParent(element);
	if (parent != null) {
	postRunnable(() -> {
	Control ctrl = fViewer.getControl();
	if (ctrl != null && !ctrl.isDisposed()) {
	if (!fFoldPackages)
	fViewer.add(parent, element);
	else
	refreshGrandParent(element);
	}
	});
	}
	return;
	}
	}
	}

	// XXX: needs to be revisited - might be a performance issue
	private void refreshGrandParent(final IModelElement element) {
	if (element instanceof IScriptFolder) {
	Object gp = getGrandParent((IScriptFolder) element);
	if (gp instanceof IModelElement) {
	IModelElement el = (IModelElement) gp;
	if (el.exists())
	fViewer.refresh(gp);
	} else if (gp instanceof IFolder) {
	IFolder folder = (IFolder) gp;
	if (folder.exists())
	fViewer.refresh(folder);
	}
	}
	}

	private Object getGrandParent(IScriptFolder element) {

	Object parent = findNextLevelParentByElementName(element);
	if (parent instanceof IProjectFragment) {
	IProjectFragment root = (IProjectFragment) parent;
	if (isRootProject(root)) {
	return root.getScriptProject();
	}
	return root;
	}

	Object grandParent = getParent(parent);
	if (grandParent == null) {
	return parent;
	}
	return grandParent;
	}

	private boolean isRootProject(IProjectFragment root) {
	if (IProjectFragment.DEFAULT_PACKAGE_ROOT.equals(root.getElementName()))
	return true;
	return false;
	}

	private void postRunnable(final Runnable r) {
	Control ctrl = fViewer.getControl();
	if (ctrl != null && !ctrl.isDisposed()) {

	Display currentDisplay = Display.getCurrent();
	if (currentDisplay != null
	&& currentDisplay.equals(ctrl.getDisplay()))
	ctrl.getDisplay().syncExec(r);
	else
	ctrl.getDisplay().asyncExec(r);
	}
	}

	/*
	* @see
	* org.eclipse.jface.util.IPropertyChangeListener#propertyChange(org.eclipse
	* .jface.util.PropertyChangeEvent)
	*/
	@Override
	public void propertyChange(PropertyChangeEvent event) {
	if (arePackagesFoldedInHierarchicalLayout() != fFoldPackages) {
	fFoldPackages = arePackagesFoldedInHierarchicalLayout();
	if (fViewer != null && !fViewer.getControl().isDisposed()) {
	fViewer.getControl().setRedraw(false);
	Object[] expandedObjects = fViewer.getExpandedElements();
	fViewer.refresh();
	fViewer.setExpandedElements(expandedObjects);
	fViewer.getControl().setRedraw(true);
	}
	}
	}

	private boolean arePackagesFoldedInHierarchicalLayout() {
	return fStore.getBoolean(
	PreferenceConstants.APPEARANCE_FOLD_PACKAGES_IN_PACKAGE_EXPLORER);
	}
	}