plugins/org.eclipse.sirius.ui/src/org/eclipse/sirius/ui/tools/internal/viewpoint/ViewpointsSelectionGraphicalHandler.java - sirius/org.eclipse.sirius - Git at Google

 /*******************************************************************************
  * Copyright (c) 2017 Obeo.
  * 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:
  *    Obeo - initial API and implementation
  *******************************************************************************/
 package org.eclipse.sirius.ui.tools.internal.viewpoint;

 import java.io.IOException;
 import java.net.URL;
 import java.util.Collection;
 import java.util.HashSet;
 import java.util.Set;

 import org.eclipse.core.resources.IResource;
 import org.eclipse.core.resources.IWorkspace;
 import org.eclipse.core.resources.ResourcesPlugin;
 import org.eclipse.core.runtime.FileLocator;
 import org.eclipse.core.runtime.IPath;
 import org.eclipse.core.runtime.Path;
 import org.eclipse.core.runtime.Platform;
 import org.eclipse.emf.common.util.URI;
 import org.eclipse.emf.ecore.resource.Resource;
 import org.eclipse.emf.edit.ui.provider.AdapterFactoryLabelProvider;
 import org.eclipse.jface.layout.GridLayoutFactory;
 import org.eclipse.jface.resource.ImageDescriptor;
 import org.eclipse.jface.resource.JFaceResources;
 import org.eclipse.jface.viewers.ArrayContentProvider;
 import org.eclipse.jface.viewers.CheckboxTableViewer;
 import org.eclipse.jface.viewers.DecorationOverlayIcon;
 import org.eclipse.jface.viewers.IDecoration;
 import org.eclipse.jface.viewers.ISelection;
 import org.eclipse.jface.viewers.ISelectionChangedListener;
 import org.eclipse.jface.viewers.IStructuredSelection;
 import org.eclipse.jface.viewers.ITableLabelProvider;
 import org.eclipse.jface.viewers.SelectionChangedEvent;
 import org.eclipse.jface.viewers.TableLayout;
 import org.eclipse.jface.viewers.TableViewer;
 import org.eclipse.jface.viewers.Viewer;
 import org.eclipse.jface.viewers.ViewerComparator;
 import org.eclipse.sirius.business.api.componentization.ViewpointRegistry;
 import org.eclipse.sirius.business.api.query.IdentifiedElementQuery;
 import org.eclipse.sirius.business.api.query.ViewpointQuery;
 import org.eclipse.sirius.business.api.session.Session;
 import org.eclipse.sirius.common.tools.api.util.StringUtil;
 import org.eclipse.sirius.ui.tools.api.views.ViewHelper;
 import org.eclipse.sirius.viewpoint.description.Viewpoint;
 import org.eclipse.sirius.viewpoint.provider.Messages;
 import org.eclipse.sirius.viewpoint.provider.SiriusEditPlugin;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.SWTError;
 import org.eclipse.swt.browser.Browser;
 import org.eclipse.swt.graphics.Font;
 import org.eclipse.swt.graphics.FontData;
 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.Table;
 import org.eclipse.swt.widgets.Text;
 import org.osgi.framework.Bundle;

 import com.google.common.base.Predicate;
 import com.google.common.collect.Collections2;
 import com.google.common.collect.Sets;

 /**
  * A graphic component providing a {@link CheckboxTableViewer} with a checkbox for each viewpoint activable/deactivable
  * regarding the given session. Also provides a browser allowing to see viewpoint description when one has focus.
  *
  * @author <a href="mailto:pierre.guilet@obeo.fr">Pierre Guilet</a>
  *
  */
 public class ViewpointsSelectionGraphicalHandler {
     /**
      * The layout of the main composite of this graphic component.
      */
     private GridLayout rootGridLayout;

     /** The browser for documentation */
     private Browser browser;

     /**
      * The composite enclosing all graphical parts of this component.
      */
     private Composite rootComposite;

     /**
      * The grid data for the browser component displaying viewpoint information.
      */
     private GridData browserGridData;

     /**
      * The viewer containing a checkbox for each viewpoint registered in the current runtime.
      */
     private CheckboxTableViewer viewer;

     /**
      * The layout data of the root component.
      */
     private GridData rootLayoutData;

     private GridData viewerGridData;

     /**
      * LayoutData of the error message top part of the browser component.
      */
     private GridData browserErrorMessageLayoutData;

     /**
      * The Text containing error message in the top part of the browser component.
      */
     private Text browserErrorMessageText;

     /**
      * The composite containing the text containing error message in the top part of the browser component.
      */
     private Composite browserErrorMessageComposite;

     /**
      * The root composite of the browser component.
      */
     private Composite browserRootComposite;

     /**
      * Return the composite enclosing all graphical parts of this component.
      *
      * @return the composite enclosing all graphical parts of this component.
      */
     public Composite getRootComposite() {
         return rootComposite;
     }

     /**
      * Return the browser providing descriptions for viewpoints taking focus.
      *
      * @return the browser providing descriptions for viewpoints taking focus.
      */
     public Browser getBrowser() {
         return browser;
     }

     /**
      * Returns the root composite of the browser component.
      *
      * @return the root composite of the browser component.
      */
     public Composite getBrowserRootComposite() {
         return browserRootComposite;
     }

     /**
      * Return all registered viewpoints that define editors for metamodel of loaded session's semantic models.
      *
      * @param session
      *            the session from which we retrieve available viewpoints.
      * @return all registered viewpoints that define editors for metamodel of loaded session's semantic models.
      */
     public Collection<Viewpoint> getAvailableViewpoints(Session session) {
         ViewpointRegistry registry = ViewpointRegistry.getInstance();

         return Collections2.filter(registry.getViewpoints(), new Predicate<Viewpoint>() {

             @Override
             public boolean apply(Viewpoint viewpoint) {
                 for (final String ext : computeSemanticFileExtensions(session)) {
                     if (new ViewpointQuery(viewpoint).handlesSemanticModelExtension(ext)) {
                         return true;
                     }
                 }
                 return false;
             }
         });
     }

     /**
      * compute the semantic file extensions to restrict the choice of viewpoint based on the session.
      *
      * @param theSession
      *            the session
      * @return a collection of file extension
      */
     public Collection<String> computeSemanticFileExtensions(Session theSession) {
         final Collection<String> extensions = new HashSet<String>();
         for (final Resource resource : theSession.getSemanticResources()) {
             if (resource != null && resource.getURI() != null) {
                 final String currentFileExtension = resource.getURI().fileExtension();
                 if (currentFileExtension != null) {
                     extensions.add(currentFileExtension);
                 }
             }
         }
         return extensions;
     }

     /**
      * Initialize graphic components.
      *
      * @param parent
      *            the composite from which we attach this graphic component.
      * @param makeColumnsEqual
      *            If true makes the two columns of the main composite equals at layout level . If false makes the two
      *            columns not equals at layout level. Refresh the layout if a modification is done.
      */
     public void createControl(final Composite parent, boolean makeColumnsEqual) {
         rootComposite = new Composite(parent, SWT.NONE);
         rootGridLayout = GridLayoutFactory.swtDefaults().numColumns(2).equalWidth(makeColumnsEqual).create();
         rootComposite.setLayout(rootGridLayout);
         rootLayoutData = new GridData(SWT.FILL, SWT.FILL, true, true);
         rootComposite.setLayoutData(rootLayoutData);

         createTableViewer(rootComposite);

         createBrowser(rootComposite);
         setBrowserInput(null);

     }

     /**
      * Initialize the graphic component that is a browser allowing to see a description for each viewpoint that has the
      * focus.
      *
      * @param parent
      *            the parent composite to be attached to.
      * @return the newly created {@link Browser}.
      */
     public Browser createBrowser(final Composite parent) {

         browserRootComposite = new Composite(parent, SWT.BORDER);
         browserRootComposite.setLayout(GridLayoutFactory.fillDefaults().create());
         browserRootComposite.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));

         browserErrorMessageComposite = new Composite(browserRootComposite, SWT.None);
         browserErrorMessageComposite.setLayout(GridLayoutFactory.fillDefaults().create());
         browserErrorMessageLayoutData = new GridData(SWT.FILL, SWT.FILL, true, false);
         browserErrorMessageComposite.setLayoutData(browserErrorMessageLayoutData);
         browserErrorMessageLayoutData.exclude = true;

         Composite browserComposite = new Composite(browserRootComposite, SWT.None);
         browserComposite.setLayout(GridLayoutFactory.fillDefaults().create());
         browserComposite.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));

         browserErrorMessageText = new Text(browserErrorMessageComposite, SWT.MULTI | SWT.WRAP);
         browserErrorMessageText.setLayoutData(new GridData(SWT.LEFT, SWT.TOP, true, false));
         browserErrorMessageText.setText(""); //$NON-NLS-1$
         browserErrorMessageText.setForeground(browserRootComposite.getDisplay().getSystemColor(SWT.COLOR_RED));
         try {
             Browser aBrowser = new Browser(browserComposite, SWT.FILL);
             browserGridData = new GridData(SWT.FILL, SWT.FILL, true, true);
             // necessary to avoid bad interaction with expandable toolkit sections
             browserGridData.widthHint = 0;
             browserGridData.heightHint = 0;
             aBrowser.setLayoutData(browserGridData);
             this.browser = aBrowser;
             return aBrowser;
         } catch (SWTError error) {
             /*
              * the browser could not be created, do not display further information
              */
             return null;
         }

     }

     /**
      * Set an error message above the viewpoint browser.
      *
      * @param errorMessage
      *            the error message to set.
      */
     public void setBrowserErrorMessageText(String errorMessage) {
         browserErrorMessageLayoutData.exclude = false;
         browserErrorMessageText.setText(errorMessage);
         browserErrorMessageComposite.setVisible(true);
         browserRootComposite.layout(true, true);
     }

     /**
      * Clear the error message above the viewpoint browser.
      */
     public void clearBrowserErrorMessageText() {
         browserErrorMessageLayoutData.exclude = true;
         browserErrorMessageText.setText(""); //$NON-NLS-1$
         browserErrorMessageComposite.setVisible(false);
         browserRootComposite.getParent().layout(true, true);
     }

     /**
      * Sets the minimum width the browser should have.
      *
      * @param minwidth
      *            the minimum width to set.
      */
     public void setBrowserMinWidth(int minwidth) {
         if (browserGridData != null) {
             browserGridData.minimumWidth = minwidth;
         }
     }

     /**
      * Returns the viewer containing a checkbox for each viewpoint registered in the current runtime.
      *
      * @return the viewer containing a checkbox for each viewpoint registered in the current runtime.
      */
     public CheckboxTableViewer getViewer() {
         return viewer;
     }

     /**
      * Create the table viewer.
      *
      * @param parent
      *            the parent composite.
      * @return the table viewer.
      */
     private TableViewer createTableViewer(final Composite parent) {
         final int style = SWT.SINGLE | SWT.H_SCROLL | SWT.V_SCROLL | SWT.BORDER;

         viewer = CheckboxTableViewer.newCheckList(parent, style);
         Table table = viewer.getTable();
         viewerGridData = new GridData(SWT.FILL, SWT.FILL, false, false);
         viewer.getControl().setLayoutData(viewerGridData);

         TableLayout layout = new TableLayout();
         table.setLayout(layout);
         table.setHeaderVisible(false);
         table.setLinesVisible(false);

         viewer.setContentProvider(new ArrayContentProvider());
         viewer.setLabelProvider(new ViewpointsTableLabelProvider());
         viewer.addSelectionChangedListener(new ISelectionChangedListener() {

             @Override
             public void selectionChanged(SelectionChangedEvent event) {
                 ISelection selection = event.getSelection();
                 if (selection instanceof IStructuredSelection) {
                     Object firstElement = ((IStructuredSelection) selection).getFirstElement();
                     if (firstElement instanceof Viewpoint) {
                         setBrowserInput((Viewpoint) firstElement);
                     }
                 }
             }
         });

         viewer.setComparator(new ViewerComparator() {
             @Override
             public int compare(Viewer theViewer, Object e1, Object e2) {
                 final String e1label = new IdentifiedElementQuery((Viewpoint) e1).getLabel();
                 final String e2label = new IdentifiedElementQuery((Viewpoint) e2).getLabel();
                 return e1label.compareTo(e2label);
             }
         });
         return viewer;
     }

     /***
      * Set the browser input.A jface like browser viewer would have been better.
      *
      * @param viewpoint
      *            the viewpoint to document
      */
     public void setBrowserInput(final Viewpoint viewpoint) {

         /* browser may be null if its creation fail */
         if (browser != null) {
             String content = null;
             if (containsHTMLDocumentation(viewpoint)) {
                 content = getContentWhenHtml(viewpoint);
             } else {
                 content = getContentWhenNoHtml(viewpoint);
             }
             browser.setText(content);
         }
     }

     /*
      * The following code (HTML handling ) and methods could move to another class.
      */
     private boolean containsHTMLDocumentation(Viewpoint viewpoint) {
         if (viewpoint != null) {
             final String doc = viewpoint.getEndUserDocumentation();
             if (!StringUtil.isEmpty(doc)) {
                 return doc.startsWith("<html>"); //$NON-NLS-1$
             }
         }
         return false;
     }

     private String getContentWhenHtml(Viewpoint viewpoint) {

         final String document = viewpoint.getEndUserDocumentation();

         Set<String> urlToRewrite = Sets.newLinkedHashSet();
         extractUrlToRewrite(document, urlToRewrite);

         return rewriteURLs(viewpoint, document, urlToRewrite);
     }

     private void extractUrlToRewrite(String document, Set<String> urlToRewrite) {
         String imgSrcPattern = "img src=\""; //$NON-NLS-1$
         int patternStartIndex = document.indexOf(imgSrcPattern);
         if (patternStartIndex != -1) {
             int imgSrcStartIndex = patternStartIndex + imgSrcPattern.length();
             int imgSrcStopIndex = document.indexOf("\"", imgSrcStartIndex); //$NON-NLS-1$
             if (imgSrcStopIndex != -1) {
                 String newToRewrite = document.substring(imgSrcStartIndex, imgSrcStopIndex);
                 urlToRewrite.add(newToRewrite);
                 extractUrlToRewrite(document.substring(imgSrcStopIndex), urlToRewrite);
             }
         }
     }

     private String rewriteURLs(Viewpoint viewpoint, String document, Set<String> urls) {

         String newDocument = document;

         for (final String url : urls) {
             newDocument = newDocument.replace(url, rewriteURL(viewpoint, url));
         }

         StringBuilder css = new StringBuilder();
         appendCss(css);
         String headClose = "</head>"; //$NON-NLS-1$
         newDocument = newDocument.replace(headClose, css.append(headClose));

         return newDocument;
     }

     private String rewriteURL(Viewpoint viewpoint, String url) {
         final URI uri = viewpoint.eResource().getURI();
         String pluginId = uri.segment(1);

         String rewrittenURL = ""; //$NON-NLS-1$

         if (uri.isPlatformPlugin()) {
             Bundle bundle = Platform.getBundle(pluginId);
             URL imageURL = bundle.getEntry(url);
             rewrittenURL = imageURL != null ? imageURL.toString() : rewrittenURL;
             if (imageURL != null) {
                 try {
                     URL fileURL = FileLocator.toFileURL(imageURL);
                     rewrittenURL = fileURL.toString();
                 } catch (IOException e) {
                     // do nothing
                 }
             }

         } else {
             final IWorkspace workspace = ResourcesPlugin.getWorkspace();
             final IPath path = new Path("/" + pluginId + url); //$NON-NLS-1$
             if (workspace.getRoot().exists(path)) {
                 IResource resource = workspace.getRoot().findMember(path);
                 rewrittenURL = resource.getLocation().toFile().toURI().toString();
             }
         }

         return rewrittenURL;
     }

     private String getContentWhenNoHtml(Viewpoint viewpoint) {
         StringBuilder content = new StringBuilder();
         return begin(content).head(content).body(content, viewpoint).end(content);
     }

     private ViewpointsSelectionGraphicalHandler begin(StringBuilder content) {
         content.append("<html>"); //$NON-NLS-1$
         return this;
     }

     private ViewpointsSelectionGraphicalHandler head(StringBuilder content) {
         content.append("<head>"); //$NON-NLS-1$
         appendCss(content);
         content.append("</head>"); //$NON-NLS-1$
         return this;
     }

     private ViewpointsSelectionGraphicalHandler body(StringBuilder content, Viewpoint viewpoint) {
         content.append("<body>"); //$NON-NLS-1$

         if (viewpoint == null) {
             content.append("<br><br><center><b>").append(Messages.ViewpointsSelectionWizardPage_documentation_title).append("</b></center>"); //$NON-NLS-1$ //$NON-NLS-2$
         } else {
             final String endUserDocumentation = viewpoint.getEndUserDocumentation();
             if (!StringUtil.isEmpty(endUserDocumentation)) {
                 content.append(viewpoint.getEndUserDocumentation());
             } else {
                 content.append(Messages.ViewpointsSelectionWizardPage_documentation_none);
             }
         }
         content.append("</body>"); //$NON-NLS-1$
         return this;
     }

     private StringBuilder appendCss(StringBuilder content) {
         Font currentFont = JFaceResources.getDialogFont();
         FontData data = currentFont.getFontData()[0];
         String fontName = data.getName();
         int fontHeight = data.getHeight() + 3;
         content.append("<style type=\"text/css\">"); //$NON-NLS-1$
         content.append("body{font-family:" + fontName + ",Arial, sans-serif;}"); //$NON-NLS-1$ //$NON-NLS-2$
         content.append("body{font-size:" + fontHeight + "px;}"); //$NON-NLS-1$ //$NON-NLS-2$
         content.append("</style>"); //$NON-NLS-1$
         return content;
     }

     private String end(StringBuilder content) {
         content.append("</html>"); //$NON-NLS-1$
         return content.toString();
     }

     private class ViewpointsTableLabelProvider extends AdapterFactoryLabelProvider implements ITableLabelProvider {

         ViewpointsTableLabelProvider() {
             super(ViewHelper.INSTANCE.createAdapterFactory());
         }

         @Override
         public Image getColumnImage(Object element, int columnIndex) {
             Image image = null;
             if (columnIndex == 0) {
                 if (element instanceof Viewpoint) {
                     final Viewpoint vp = (Viewpoint) element;
                     if (vp.getIcon() != null && vp.getIcon().length() > 0) {
                         final ImageDescriptor desc = SiriusEditPlugin.Implementation.findImageDescriptor(vp.getIcon());
                         if (desc != null) {
                             image = SiriusEditPlugin.getPlugin().getImage(desc);
                             image = getEnhancedImage(image, vp);
                         }
                     }
                     if (image == null) {
                         image = SiriusEditPlugin.getPlugin().getImage(SiriusEditPlugin.getPlugin().getItemImageDescriptor(vp));
                         image = getEnhancedImage(image, vp);
                     }
                 } else {
                     image = super.getImage(element);
                 }
             }
             return image;
         }

         private ImageDescriptor getOverlayedDescriptor(final Image baseImage, final String decoratorPath) {
             final ImageDescriptor decoratorDescriptor = SiriusEditPlugin.Implementation.getBundledImageDescriptor(decoratorPath);
             return new DecorationOverlayIcon(baseImage, decoratorDescriptor, IDecoration.BOTTOM_LEFT);
         }

         private Image getEnhancedImage(final Image image, final Viewpoint viewpoint) {
             // Add decorator if the viewpoint comes from workspace
             if (!ViewpointRegistry.getInstance().isFromPlugin(viewpoint) && image != null) {
                 return SiriusEditPlugin.getPlugin().getImage(getOverlayedDescriptor(image, "icons/full/decorator/folder_close.gif")); //$NON-NLS-1$
             }
             return image;
         }
     }

     /**
      * Sets the height the enclosing root composite of the viewpoints block must have.
      *
      * @param height
      *            the height to set.
      */
     public void setHeight(int height) {
         viewerGridData.grabExcessVerticalSpace = false;
         viewerGridData.heightHint = height;
     }
 }
	/*******************************************************************************
	* Copyright (c) 2017 Obeo.
	* 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:
	* Obeo - initial API and implementation
	*******************************************************************************/
	package org.eclipse.sirius.ui.tools.internal.viewpoint;

	import java.io.IOException;
	import java.net.URL;
	import java.util.Collection;
	import java.util.HashSet;
	import java.util.Set;

	import org.eclipse.core.resources.IResource;
	import org.eclipse.core.resources.IWorkspace;
	import org.eclipse.core.resources.ResourcesPlugin;
	import org.eclipse.core.runtime.FileLocator;
	import org.eclipse.core.runtime.IPath;
	import org.eclipse.core.runtime.Path;
	import org.eclipse.core.runtime.Platform;
	import org.eclipse.emf.common.util.URI;
	import org.eclipse.emf.ecore.resource.Resource;
	import org.eclipse.emf.edit.ui.provider.AdapterFactoryLabelProvider;
	import org.eclipse.jface.layout.GridLayoutFactory;
	import org.eclipse.jface.resource.ImageDescriptor;
	import org.eclipse.jface.resource.JFaceResources;
	import org.eclipse.jface.viewers.ArrayContentProvider;
	import org.eclipse.jface.viewers.CheckboxTableViewer;
	import org.eclipse.jface.viewers.DecorationOverlayIcon;
	import org.eclipse.jface.viewers.IDecoration;
	import org.eclipse.jface.viewers.ISelection;
	import org.eclipse.jface.viewers.ISelectionChangedListener;
	import org.eclipse.jface.viewers.IStructuredSelection;
	import org.eclipse.jface.viewers.ITableLabelProvider;
	import org.eclipse.jface.viewers.SelectionChangedEvent;
	import org.eclipse.jface.viewers.TableLayout;
	import org.eclipse.jface.viewers.TableViewer;
	import org.eclipse.jface.viewers.Viewer;
	import org.eclipse.jface.viewers.ViewerComparator;
	import org.eclipse.sirius.business.api.componentization.ViewpointRegistry;
	import org.eclipse.sirius.business.api.query.IdentifiedElementQuery;
	import org.eclipse.sirius.business.api.query.ViewpointQuery;
	import org.eclipse.sirius.business.api.session.Session;
	import org.eclipse.sirius.common.tools.api.util.StringUtil;
	import org.eclipse.sirius.ui.tools.api.views.ViewHelper;
	import org.eclipse.sirius.viewpoint.description.Viewpoint;
	import org.eclipse.sirius.viewpoint.provider.Messages;
	import org.eclipse.sirius.viewpoint.provider.SiriusEditPlugin;
	import org.eclipse.swt.SWT;
	import org.eclipse.swt.SWTError;
	import org.eclipse.swt.browser.Browser;
	import org.eclipse.swt.graphics.Font;
	import org.eclipse.swt.graphics.FontData;
	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.Table;
	import org.eclipse.swt.widgets.Text;
	import org.osgi.framework.Bundle;

	import com.google.common.base.Predicate;
	import com.google.common.collect.Collections2;
	import com.google.common.collect.Sets;

	/**
	* A graphic component providing a {@link CheckboxTableViewer} with a checkbox for each viewpoint activable/deactivable
	* regarding the given session. Also provides a browser allowing to see viewpoint description when one has focus.
	*
	* @author <a href="mailto:pierre.guilet@obeo.fr">Pierre Guilet</a>
	*
	*/
	public class ViewpointsSelectionGraphicalHandler {
	/**
	* The layout of the main composite of this graphic component.
	*/
	private GridLayout rootGridLayout;

	/** The browser for documentation */
	private Browser browser;

	/**
	* The composite enclosing all graphical parts of this component.
	*/
	private Composite rootComposite;

	/**
	* The grid data for the browser component displaying viewpoint information.
	*/
	private GridData browserGridData;

	/**
	* The viewer containing a checkbox for each viewpoint registered in the current runtime.
	*/
	private CheckboxTableViewer viewer;

	/**
	* The layout data of the root component.
	*/
	private GridData rootLayoutData;

	private GridData viewerGridData;

	/**
	* LayoutData of the error message top part of the browser component.
	*/
	private GridData browserErrorMessageLayoutData;

	/**
	* The Text containing error message in the top part of the browser component.
	*/
	private Text browserErrorMessageText;

	/**
	* The composite containing the text containing error message in the top part of the browser component.
	*/
	private Composite browserErrorMessageComposite;

	/**
	* The root composite of the browser component.
	*/
	private Composite browserRootComposite;

	/**
	* Return the composite enclosing all graphical parts of this component.
	*
	* @return the composite enclosing all graphical parts of this component.
	*/
	public Composite getRootComposite() {
	return rootComposite;
	}

	/**
	* Return the browser providing descriptions for viewpoints taking focus.
	*
	* @return the browser providing descriptions for viewpoints taking focus.
	*/
	public Browser getBrowser() {
	return browser;
	}

	/**
	* Returns the root composite of the browser component.
	*
	* @return the root composite of the browser component.
	*/
	public Composite getBrowserRootComposite() {
	return browserRootComposite;
	}

	/**
	* Return all registered viewpoints that define editors for metamodel of loaded session's semantic models.
	*
	* @param session
	* the session from which we retrieve available viewpoints.
	* @return all registered viewpoints that define editors for metamodel of loaded session's semantic models.
	*/
	public Collection<Viewpoint> getAvailableViewpoints(Session session) {
	ViewpointRegistry registry = ViewpointRegistry.getInstance();

	return Collections2.filter(registry.getViewpoints(), new Predicate<Viewpoint>() {

	@Override
	public boolean apply(Viewpoint viewpoint) {
	for (final String ext : computeSemanticFileExtensions(session)) {
	if (new ViewpointQuery(viewpoint).handlesSemanticModelExtension(ext)) {
	return true;
	}
	}
	return false;
	}
	});
	}

	/**
	* compute the semantic file extensions to restrict the choice of viewpoint based on the session.
	*
	* @param theSession
	* the session
	* @return a collection of file extension
	*/
	public Collection<String> computeSemanticFileExtensions(Session theSession) {
	final Collection<String> extensions = new HashSet<String>();
	for (final Resource resource : theSession.getSemanticResources()) {
	if (resource != null && resource.getURI() != null) {
	final String currentFileExtension = resource.getURI().fileExtension();
	if (currentFileExtension != null) {
	extensions.add(currentFileExtension);
	}
	}
	}
	return extensions;
	}

	/**
	* Initialize graphic components.
	*
	* @param parent
	* the composite from which we attach this graphic component.
	* @param makeColumnsEqual
	* If true makes the two columns of the main composite equals at layout level . If false makes the two
	* columns not equals at layout level. Refresh the layout if a modification is done.
	*/
	public void createControl(final Composite parent, boolean makeColumnsEqual) {
	rootComposite = new Composite(parent, SWT.NONE);
	rootGridLayout = GridLayoutFactory.swtDefaults().numColumns(2).equalWidth(makeColumnsEqual).create();
	rootComposite.setLayout(rootGridLayout);
	rootLayoutData = new GridData(SWT.FILL, SWT.FILL, true, true);
	rootComposite.setLayoutData(rootLayoutData);

	createTableViewer(rootComposite);

	createBrowser(rootComposite);
	setBrowserInput(null);

	}

	/**
	* Initialize the graphic component that is a browser allowing to see a description for each viewpoint that has the
	* focus.
	*
	* @param parent
	* the parent composite to be attached to.
	* @return the newly created {@link Browser}.
	*/
	public Browser createBrowser(final Composite parent) {

	browserRootComposite = new Composite(parent, SWT.BORDER);
	browserRootComposite.setLayout(GridLayoutFactory.fillDefaults().create());
	browserRootComposite.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));

	browserErrorMessageComposite = new Composite(browserRootComposite, SWT.None);
	browserErrorMessageComposite.setLayout(GridLayoutFactory.fillDefaults().create());
	browserErrorMessageLayoutData = new GridData(SWT.FILL, SWT.FILL, true, false);
	browserErrorMessageComposite.setLayoutData(browserErrorMessageLayoutData);
	browserErrorMessageLayoutData.exclude = true;

	Composite browserComposite = new Composite(browserRootComposite, SWT.None);
	browserComposite.setLayout(GridLayoutFactory.fillDefaults().create());
	browserComposite.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));

	browserErrorMessageText = new Text(browserErrorMessageComposite, SWT.MULTI \| SWT.WRAP);
	browserErrorMessageText.setLayoutData(new GridData(SWT.LEFT, SWT.TOP, true, false));
	browserErrorMessageText.setText(""); //$NON-NLS-1$
	browserErrorMessageText.setForeground(browserRootComposite.getDisplay().getSystemColor(SWT.COLOR_RED));
	try {
	Browser aBrowser = new Browser(browserComposite, SWT.FILL);
	browserGridData = new GridData(SWT.FILL, SWT.FILL, true, true);
	// necessary to avoid bad interaction with expandable toolkit sections
	browserGridData.widthHint = 0;
	browserGridData.heightHint = 0;
	aBrowser.setLayoutData(browserGridData);
	this.browser = aBrowser;
	return aBrowser;
	} catch (SWTError error) {
	/*
	* the browser could not be created, do not display further information
	*/
	return null;
	}

	}

	/**
	* Set an error message above the viewpoint browser.
	*
	* @param errorMessage
	* the error message to set.
	*/
	public void setBrowserErrorMessageText(String errorMessage) {
	browserErrorMessageLayoutData.exclude = false;
	browserErrorMessageText.setText(errorMessage);
	browserErrorMessageComposite.setVisible(true);
	browserRootComposite.layout(true, true);
	}

	/**
	* Clear the error message above the viewpoint browser.
	*/
	public void clearBrowserErrorMessageText() {
	browserErrorMessageLayoutData.exclude = true;
	browserErrorMessageText.setText(""); //$NON-NLS-1$
	browserErrorMessageComposite.setVisible(false);
	browserRootComposite.getParent().layout(true, true);
	}

	/**
	* Sets the minimum width the browser should have.
	*
	* @param minwidth
	* the minimum width to set.
	*/
	public void setBrowserMinWidth(int minwidth) {
	if (browserGridData != null) {
	browserGridData.minimumWidth = minwidth;
	}
	}

	/**
	* Returns the viewer containing a checkbox for each viewpoint registered in the current runtime.
	*
	* @return the viewer containing a checkbox for each viewpoint registered in the current runtime.
	*/
	public CheckboxTableViewer getViewer() {
	return viewer;
	}

	/**
	* Create the table viewer.
	*
	* @param parent
	* the parent composite.
	* @return the table viewer.
	*/
	private TableViewer createTableViewer(final Composite parent) {
	final int style = SWT.SINGLE \| SWT.H_SCROLL \| SWT.V_SCROLL \| SWT.BORDER;

	viewer = CheckboxTableViewer.newCheckList(parent, style);
	Table table = viewer.getTable();
	viewerGridData = new GridData(SWT.FILL, SWT.FILL, false, false);
	viewer.getControl().setLayoutData(viewerGridData);

	TableLayout layout = new TableLayout();
	table.setLayout(layout);
	table.setHeaderVisible(false);
	table.setLinesVisible(false);

	viewer.setContentProvider(new ArrayContentProvider());
	viewer.setLabelProvider(new ViewpointsTableLabelProvider());
	viewer.addSelectionChangedListener(new ISelectionChangedListener() {

	@Override
	public void selectionChanged(SelectionChangedEvent event) {
	ISelection selection = event.getSelection();
	if (selection instanceof IStructuredSelection) {
	Object firstElement = ((IStructuredSelection) selection).getFirstElement();
	if (firstElement instanceof Viewpoint) {
	setBrowserInput((Viewpoint) firstElement);
	}
	}
	}
	});

	viewer.setComparator(new ViewerComparator() {
	@Override
	public int compare(Viewer theViewer, Object e1, Object e2) {
	final String e1label = new IdentifiedElementQuery((Viewpoint) e1).getLabel();
	final String e2label = new IdentifiedElementQuery((Viewpoint) e2).getLabel();
	return e1label.compareTo(e2label);
	}
	});
	return viewer;
	}

	/***
	* Set the browser input.A jface like browser viewer would have been better.
	*
	* @param viewpoint
	* the viewpoint to document
	*/
	public void setBrowserInput(final Viewpoint viewpoint) {

	/* browser may be null if its creation fail */
	if (browser != null) {
	String content = null;
	if (containsHTMLDocumentation(viewpoint)) {
	content = getContentWhenHtml(viewpoint);
	} else {
	content = getContentWhenNoHtml(viewpoint);
	}
	browser.setText(content);
	}
	}

	/*
	* The following code (HTML handling ) and methods could move to another class.
	*/
	private boolean containsHTMLDocumentation(Viewpoint viewpoint) {
	if (viewpoint != null) {
	final String doc = viewpoint.getEndUserDocumentation();
	if (!StringUtil.isEmpty(doc)) {
	return doc.startsWith("<html>"); //$NON-NLS-1$
	}
	}
	return false;
	}

	private String getContentWhenHtml(Viewpoint viewpoint) {

	final String document = viewpoint.getEndUserDocumentation();

	Set<String> urlToRewrite = Sets.newLinkedHashSet();
	extractUrlToRewrite(document, urlToRewrite);

	return rewriteURLs(viewpoint, document, urlToRewrite);
	}

	private void extractUrlToRewrite(String document, Set<String> urlToRewrite) {
	String imgSrcPattern = "img src=\""; //$NON-NLS-1$
	int patternStartIndex = document.indexOf(imgSrcPattern);
	if (patternStartIndex != -1) {
	int imgSrcStartIndex = patternStartIndex + imgSrcPattern.length();
	int imgSrcStopIndex = document.indexOf("\"", imgSrcStartIndex); //$NON-NLS-1$
	if (imgSrcStopIndex != -1) {
	String newToRewrite = document.substring(imgSrcStartIndex, imgSrcStopIndex);
	urlToRewrite.add(newToRewrite);
	extractUrlToRewrite(document.substring(imgSrcStopIndex), urlToRewrite);
	}
	}
	}

	private String rewriteURLs(Viewpoint viewpoint, String document, Set<String> urls) {

	String newDocument = document;

	for (final String url : urls) {
	newDocument = newDocument.replace(url, rewriteURL(viewpoint, url));
	}

	StringBuilder css = new StringBuilder();
	appendCss(css);
	String headClose = "</head>"; //$NON-NLS-1$
	newDocument = newDocument.replace(headClose, css.append(headClose));

	return newDocument;
	}

	private String rewriteURL(Viewpoint viewpoint, String url) {
	final URI uri = viewpoint.eResource().getURI();
	String pluginId = uri.segment(1);

	String rewrittenURL = ""; //$NON-NLS-1$

	if (uri.isPlatformPlugin()) {
	Bundle bundle = Platform.getBundle(pluginId);
	URL imageURL = bundle.getEntry(url);
	rewrittenURL = imageURL != null ? imageURL.toString() : rewrittenURL;
	if (imageURL != null) {
	try {
	URL fileURL = FileLocator.toFileURL(imageURL);
	rewrittenURL = fileURL.toString();
	} catch (IOException e) {
	// do nothing
	}
	}

	} else {
	final IWorkspace workspace = ResourcesPlugin.getWorkspace();
	final IPath path = new Path("/" + pluginId + url); //$NON-NLS-1$
	if (workspace.getRoot().exists(path)) {
	IResource resource = workspace.getRoot().findMember(path);
	rewrittenURL = resource.getLocation().toFile().toURI().toString();
	}
	}

	return rewrittenURL;
	}

	private String getContentWhenNoHtml(Viewpoint viewpoint) {
	StringBuilder content = new StringBuilder();
	return begin(content).head(content).body(content, viewpoint).end(content);
	}

	private ViewpointsSelectionGraphicalHandler begin(StringBuilder content) {
	content.append("<html>"); //$NON-NLS-1$
	return this;
	}

	private ViewpointsSelectionGraphicalHandler head(StringBuilder content) {
	content.append("<head>"); //$NON-NLS-1$
	appendCss(content);
	content.append("</head>"); //$NON-NLS-1$
	return this;
	}

	private ViewpointsSelectionGraphicalHandler body(StringBuilder content, Viewpoint viewpoint) {
	content.append("<body>"); //$NON-NLS-1$

	if (viewpoint == null) {
	content.append("<br><br><center><b>").append(Messages.ViewpointsSelectionWizardPage_documentation_title).append("</b></center>"); //$NON-NLS-1$ //$NON-NLS-2$
	} else {
	final String endUserDocumentation = viewpoint.getEndUserDocumentation();
	if (!StringUtil.isEmpty(endUserDocumentation)) {
	content.append(viewpoint.getEndUserDocumentation());
	} else {
	content.append(Messages.ViewpointsSelectionWizardPage_documentation_none);
	}
	}
	content.append("</body>"); //$NON-NLS-1$
	return this;
	}

	private StringBuilder appendCss(StringBuilder content) {
	Font currentFont = JFaceResources.getDialogFont();
	FontData data = currentFont.getFontData()[0];
	String fontName = data.getName();
	int fontHeight = data.getHeight() + 3;
	content.append("<style type=\"text/css\">"); //$NON-NLS-1$
	content.append("body{font-family:" + fontName + ",Arial, sans-serif;}"); //$NON-NLS-1$ //$NON-NLS-2$
	content.append("body{font-size:" + fontHeight + "px;}"); //$NON-NLS-1$ //$NON-NLS-2$
	content.append("</style>"); //$NON-NLS-1$
	return content;
	}

	private String end(StringBuilder content) {
	content.append("</html>"); //$NON-NLS-1$
	return content.toString();
	}

	private class ViewpointsTableLabelProvider extends AdapterFactoryLabelProvider implements ITableLabelProvider {

	ViewpointsTableLabelProvider() {
	super(ViewHelper.INSTANCE.createAdapterFactory());
	}

	@Override
	public Image getColumnImage(Object element, int columnIndex) {
	Image image = null;
	if (columnIndex == 0) {
	if (element instanceof Viewpoint) {
	final Viewpoint vp = (Viewpoint) element;
	if (vp.getIcon() != null && vp.getIcon().length() > 0) {
	final ImageDescriptor desc = SiriusEditPlugin.Implementation.findImageDescriptor(vp.getIcon());
	if (desc != null) {
	image = SiriusEditPlugin.getPlugin().getImage(desc);
	image = getEnhancedImage(image, vp);
	}
	}
	if (image == null) {
	image = SiriusEditPlugin.getPlugin().getImage(SiriusEditPlugin.getPlugin().getItemImageDescriptor(vp));
	image = getEnhancedImage(image, vp);
	}
	} else {
	image = super.getImage(element);
	}
	}
	return image;
	}

	private ImageDescriptor getOverlayedDescriptor(final Image baseImage, final String decoratorPath) {
	final ImageDescriptor decoratorDescriptor = SiriusEditPlugin.Implementation.getBundledImageDescriptor(decoratorPath);
	return new DecorationOverlayIcon(baseImage, decoratorDescriptor, IDecoration.BOTTOM_LEFT);
	}

	private Image getEnhancedImage(final Image image, final Viewpoint viewpoint) {
	// Add decorator if the viewpoint comes from workspace
	if (!ViewpointRegistry.getInstance().isFromPlugin(viewpoint) && image != null) {
	return SiriusEditPlugin.getPlugin().getImage(getOverlayedDescriptor(image, "icons/full/decorator/folder_close.gif")); //$NON-NLS-1$
	}
	return image;
	}
	}

	/**
	* Sets the height the enclosing root composite of the viewpoints block must have.
	*
	* @param height
	* the height to set.
	*/
	public void setHeight(int height) {
	viewerGridData.grabExcessVerticalSpace = false;
	viewerGridData.heightHint = height;
	}
	}