bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/dialogs/PathVariablesGroup.java - platform/eclipse.platform.ui - Git at Google

 /*******************************************************************************
  * Copyright (c) 2000, 2005 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
  *******************************************************************************/
 package org.eclipse.ui.internal.ide.dialogs;

 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.Map;
 import java.util.Set;
 import java.util.SortedMap;
 import java.util.TreeMap;

 import org.eclipse.core.filesystem.IFileInfo;
 import org.eclipse.core.resources.IPathVariableManager;
 import org.eclipse.core.resources.IResource;
 import org.eclipse.core.resources.ResourcesPlugin;
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IPath;
 import org.eclipse.core.runtime.Path;
 import org.eclipse.jface.dialogs.Dialog;
 import org.eclipse.jface.dialogs.ErrorDialog;
 import org.eclipse.jface.dialogs.IDialogConstants;
 import org.eclipse.jface.resource.ImageDescriptor;
 import org.eclipse.jface.window.Window;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.events.SelectionAdapter;
 import org.eclipse.swt.events.SelectionEvent;
 import org.eclipse.swt.graphics.Font;
 import org.eclipse.swt.graphics.FontMetrics;
 import org.eclipse.swt.graphics.GC;
 import org.eclipse.swt.graphics.Image;
 import org.eclipse.swt.layout.GridData;
 import org.eclipse.swt.layout.GridLayout;
 import org.eclipse.swt.widgets.Button;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Control;
 import org.eclipse.swt.widgets.Event;
 import org.eclipse.swt.widgets.Label;
 import org.eclipse.swt.widgets.Listener;
 import org.eclipse.swt.widgets.Shell;
 import org.eclipse.swt.widgets.Table;
 import org.eclipse.swt.widgets.TableItem;
 import org.eclipse.ui.ISharedImages;
 import org.eclipse.ui.PlatformUI;
 import org.eclipse.ui.internal.ide.IDEWorkbenchMessages;
 import org.eclipse.ui.internal.ide.IDEWorkbenchPlugin;
 import org.eclipse.ui.plugin.AbstractUIPlugin;

 /**
  * A widget group that displays path variables.
  * Includes buttons to edit, remove existing variables and create new ones.
  *
  * @since 2.1
  */
 public class PathVariablesGroup {
     /**
      * Simple data structure that holds a path variable name/value pair.
      */
     public static class PathVariableElement {
         /**
          * The name of the element.
          */
         public String name;

         /**
          * The path of the element.
          */
         public IPath path;
     }

     // sizing constants
     private static final int SIZING_SELECTION_PANE_WIDTH = 400;

     // parent shell
     private Shell shell;

     private Label variableLabel;

     private Table variableTable;

     private Button addButton;

     private Button editButton;

     private Button removeButton;

     // used to compute layout sizes
     private FontMetrics fontMetrics;

     // create a multi select table
     private boolean multiSelect;

     // IResource.FILE and/or IResource.FOLDER
     private int variableType;

     // External listener called when the table selection changes
     private Listener selectionListener;

     // temporary collection for keeping currently defined variables
     private SortedMap tempPathVariables;

     // set of removed variables' names
     private Set removedVariableNames;

     // reference to the workspace's path variable manager
     private IPathVariableManager pathVariableManager;

     // file image
     private final Image FILE_IMG = PlatformUI.getWorkbench().getSharedImages()
             .getImage(ISharedImages.IMG_OBJ_FILE);

     // folder image
     private final Image FOLDER_IMG = PlatformUI.getWorkbench()
             .getSharedImages().getImage(ISharedImages.IMG_OBJ_FOLDER);

     // unknown (non-existent) image. created locally, dispose locally
     private Image imageUnkown;

     /**
      * Creates a new PathVariablesGroup.
      *
      * @param multiSelect create a multi select tree
      * @param variableType the type of variables that are displayed in
      * 	the widget group. <code>IResource.FILE</code> and/or <code>IResource.FOLDER</code>
      * 	logically ORed together.
      */
     public PathVariablesGroup(boolean multiSelect, int variableType) {
         this.multiSelect = multiSelect;
         this.variableType = variableType;
         pathVariableManager = ResourcesPlugin.getWorkspace()
                 .getPathVariableManager();
         removedVariableNames = new HashSet();
         tempPathVariables = new TreeMap();
         // initialize internal model
         initTemporaryState();
     }

     /**
      * Creates a new PathVariablesGroup.
      *
      * @param multiSelect create a multi select tree
      * @param variableType the type of variables that are displayed in
      * 	the widget group. <code>IResource.FILE</code> and/or <code>IResource.FOLDER</code>
      * 	logically ORed together.
      * @param selectionListener listener notified when the selection changes
      * 	in the variables list.
      */
     public PathVariablesGroup(boolean multiSelect, int variableType,
             Listener selectionListener) {
         this(multiSelect, variableType);
         this.selectionListener = selectionListener;
     }

     /**
      * Opens a dialog for creating a new variable.
      */
     private void addNewVariable() {
         // constructs a dialog for editing the new variable's current name and value
         PathVariableDialog dialog = new PathVariableDialog(shell,
                 PathVariableDialog.NEW_VARIABLE, variableType,
                 pathVariableManager, tempPathVariables.keySet());

         // opens the dialog - just returns if the user cancels it
         if (dialog.open() == Window.CANCEL)
             return;

         // otherwise, adds the new variable (or updates an existing one) in the
         // temporary collection of currently defined variables
         String newVariableName = dialog.getVariableName();
         IPath newVariableValue = new Path(dialog.getVariableValue());
         tempPathVariables.put(newVariableName, newVariableValue);

         // the UI must be updated
         updateWidgetState(newVariableName);
     }

     /**
      * Creates the widget group.
      * Callers must call <code>dispose</code> when the group is no
      * longer needed.
      *
      * @param parent the widget parent
      * @return container of the widgets
      */
     public Control createContents(Composite parent) {
         Font font = parent.getFont();

         if (imageUnkown == null) {
             ImageDescriptor descriptor = AbstractUIPlugin
                     .imageDescriptorFromPlugin(
                             IDEWorkbenchPlugin.IDE_WORKBENCH,
                             "$nl$/icons/full/obj16/warning.gif"); //$NON-NLS-1$
             imageUnkown = descriptor.createImage();
         }
         initializeDialogUnits(parent);
         shell = parent.getShell();

         // define container & its layout
         Composite pageComponent = new Composite(parent, SWT.NULL);
         GridLayout layout = new GridLayout();
         layout.numColumns = 2;
         layout.marginWidth = 0;
         layout.marginHeight = 0;
         pageComponent.setLayout(layout);
         GridData data = new GridData(GridData.FILL_BOTH);
         data.widthHint = SIZING_SELECTION_PANE_WIDTH;
         pageComponent.setLayoutData(data);
         pageComponent.setFont(font);

         // layout the table & its buttons
         variableLabel = new Label(pageComponent, SWT.LEFT);
         variableLabel.setText(IDEWorkbenchMessages.PathVariablesBlock_variablesLabel);
         data = new GridData();
         data.horizontalAlignment = GridData.FILL;
         data.horizontalSpan = 2;
         variableLabel.setLayoutData(data);
         variableLabel.setFont(font);

         int tableStyle = SWT.BORDER | SWT.FULL_SELECTION;
         if (multiSelect) {
             tableStyle |= SWT.MULTI;
         }
         variableTable = new Table(pageComponent, tableStyle);
         variableTable.addSelectionListener(new SelectionAdapter() {
             public void widgetSelected(SelectionEvent e) {
                 updateEnabledState();
                 if (selectionListener != null)
                     selectionListener.handleEvent(new Event());
             }
         });
         data = new GridData(GridData.FILL_BOTH);
         data.heightHint = variableTable.getItemHeight() * 7;
         variableTable.setLayoutData(data);
         variableTable.setFont(font);

         createButtonGroup(pageComponent);
         // populate table with current internal state and set buttons' initial state
         updateWidgetState(null);

         return pageComponent;
     }

     /**
      * Disposes the group's resources.
      */
     public void dispose() {
         if (imageUnkown != null) {
             imageUnkown.dispose();
             imageUnkown = null;
         }
     }

     /**
      * Opens a dialog for editing an existing variable.
      *
      * @see PathVariableDialog
      */
     private void editSelectedVariable() {
         // retrieves the name and value for the currently selected variable
         TableItem item = variableTable.getItem(variableTable
                 .getSelectionIndex());
         String variableName = (String) item.getData();
         IPath variableValue = (IPath) tempPathVariables.get(variableName);

         // constructs a dialog for editing the variable's current name and value
         PathVariableDialog dialog = new PathVariableDialog(shell,
                 PathVariableDialog.EXISTING_VARIABLE, variableType,
                 pathVariableManager, tempPathVariables.keySet());
         dialog.setVariableName(variableName);
         dialog.setVariableValue(variableValue.toOSString());

         // opens the dialog - just returns if the user cancels it
         if (dialog.open() == Window.CANCEL)
             return;

         // the name can be changed, so we remove the current variable definition...
         removedVariableNames.add(variableName);
         tempPathVariables.remove(variableName);

         String newVariableName = dialog.getVariableName();
         IPath newVariableValue = new Path(dialog.getVariableValue());

         // and add it again (maybe with a different name)
         tempPathVariables.put(newVariableName, newVariableValue);

         // now we must refresh the UI state
         updateWidgetState(newVariableName);

     }

     /**
      * Returns the enabled state of the group's widgets.
      * Returns <code>true</code> if called prior to calling
      * <code>createContents</code>.
      *
      * @return boolean the enabled state of the group's widgets.
      * 	 <code>true</code> if called prior to calling <code>createContents</code>.
      */
     public boolean getEnabled() {
         if (variableTable != null && !variableTable.isDisposed()) {
             return variableTable.getEnabled();
         }
         return true;
     }

     /**
      * Returns the selected variables.
      *
      * @return the selected variables. Returns an empty array if
      * 	the widget group has not been created yet by calling
      * 	<code>createContents</code>
      */
     public PathVariableElement[] getSelection() {
         if (variableTable == null) {
             return new PathVariableElement[0];
         }
         TableItem[] items = variableTable.getSelection();
         PathVariableElement[] selection = new PathVariableElement[items.length];

         for (int i = 0; i < items.length; i++) {
             String name = (String) items[i].getData();
             selection[i] = new PathVariableElement();
             selection[i].name = name;
             selection[i].path = (IPath) tempPathVariables.get(name);
         }
         return selection;
     }

     /**
      * Creates the add/edit/remove buttons
      *
      * @param parent the widget parent
      */
     private void createButtonGroup(Composite parent) {
         Font font = parent.getFont();
         Composite groupComponent = new Composite(parent, SWT.NULL);
         GridLayout groupLayout = new GridLayout();
         groupLayout.marginWidth = 0;
         groupLayout.marginHeight = 0;
         groupComponent.setLayout(groupLayout);
         GridData data = new GridData();
         data.verticalAlignment = GridData.FILL;
         data.horizontalAlignment = GridData.FILL;
         groupComponent.setLayoutData(data);
         groupComponent.setFont(font);

         addButton = new Button(groupComponent, SWT.PUSH);
         addButton.setText(IDEWorkbenchMessages.PathVariablesBlock_addVariableButton);
         addButton.addSelectionListener(new SelectionAdapter() {
             public void widgetSelected(SelectionEvent e) {
                 addNewVariable();
             }
         });
         addButton.setFont(font);
         setButtonLayoutData(addButton);

         editButton = new Button(groupComponent, SWT.PUSH);
         editButton.setText(IDEWorkbenchMessages.PathVariablesBlock_editVariableButton);
         editButton.addSelectionListener(new SelectionAdapter() {
             public void widgetSelected(SelectionEvent e) {
                 editSelectedVariable();
             }
         });
         editButton.setFont(font);
         setButtonLayoutData(editButton);

         removeButton = new Button(groupComponent, SWT.PUSH);
         removeButton.setText(IDEWorkbenchMessages.PathVariablesBlock_removeVariableButton);
         removeButton.addSelectionListener(new SelectionAdapter() {
             public void widgetSelected(SelectionEvent e) {
                 removeSelectedVariables();
             }
         });
         removeButton.setFont(font);
         setButtonLayoutData(removeButton);
     }

     /**
      * Initializes the computation of horizontal and vertical dialog units
      * based on the size of current font.
      * <p>
      * This method must be called before <code>setButtonLayoutData</code>
      * is called.
      * </p>
      *
      * @param control a control from which to obtain the current font
      */
     protected void initializeDialogUnits(Control control) {
         // Compute and store a font metric
         GC gc = new GC(control);
         gc.setFont(control.getFont());
         fontMetrics = gc.getFontMetrics();
         gc.dispose();
     }

     /**
      * (Re-)Initialize collections used to mantain temporary variable state.
      */
     private void initTemporaryState() {
         String[] varNames = pathVariableManager.getPathVariableNames();

         tempPathVariables.clear();
         for (int i = 0; i < varNames.length; i++) {
             IPath value = pathVariableManager.getValue(varNames[i]);

             // the value may not exist any more
             if (value != null) {
                 boolean isFile = value.toFile().isFile();
                 if ((isFile && (variableType & IResource.FILE) != 0)
                         || (isFile == false && (variableType & IResource.FOLDER) != 0)) {

                     tempPathVariables.put(varNames[i], value);
                 }
             }
         }
         removedVariableNames.clear();
     }

     /**
      * Updates button enabled state, depending on the number of currently selected
      * variables in the table.
      */
     private void updateEnabledState() {
         int itemsSelectedCount = variableTable.getSelectionCount();
         editButton.setEnabled(itemsSelectedCount == 1);
         removeButton.setEnabled(itemsSelectedCount > 0);
     }

     /**
      * Rebuilds table widget state with the current list of variables (reflecting
      * any changes, additions and removals), and selects the item corresponding to
      * the given variable name. If the variable name is <code>null</code>, the
      * first item (if any) will be selected.
      *
      * @param selectedVarName the name for the variable to be selected (may be
      * <code>null</code>)
      * @see IPathVariableManager#getPathVariableNames()
      * @see IPathVariableManager#getValue(String)
      */
     private void updateVariableTable(String selectedVarName) {
         variableTable.removeAll();
         int selectedVarIndex = 0;
         for (Iterator varNames = tempPathVariables.keySet().iterator(); varNames
                 .hasNext();) {
             TableItem item = new TableItem(variableTable, SWT.NONE);
             String varName = (String) varNames.next();
             IPath value = (IPath) tempPathVariables.get(varName);
             IFileInfo file = IDEResourceInfoUtils.getFileInfo(value);

             item.setText(varName + " - " + value.toOSString()); //$NON-NLS-1$
             // the corresponding variable name is stored in each table widget item
             item.setData(varName);
             item.setImage(file.exists() ? (file.isDirectory() ? FOLDER_IMG
                     : FILE_IMG ) : imageUnkown);
             if (varName.equals(selectedVarName))
                 selectedVarIndex = variableTable.getItemCount() - 1;
         }
         if (variableTable.getItemCount() > selectedVarIndex) {
             variableTable.setSelection(selectedVarIndex);
             if (selectionListener != null)
                 selectionListener.handleEvent(new Event());
         } else if (variableTable.getItemCount() == 0
                 && selectionListener != null)
             selectionListener.handleEvent(new Event());
     }

     /**
      * Commits the temporary state to the path variable manager in response to user
      * confirmation.
      * @return boolean <code>true</code> if there were no problems.
      * @see IPathVariableManager#setValue(String, IPath)
      */
     public boolean performOk() {
         try {
             // first process removed variables
             for (Iterator removed = removedVariableNames.iterator(); removed
                     .hasNext();) {
                 String removedVariableName = (String) removed.next();
                 // only removes variables that have not been added again
                 if (!tempPathVariables.containsKey(removedVariableName))
                     pathVariableManager.setValue(removedVariableName, null);
             }

             // then process the current collection of variables, adding/updating them
             for (Iterator current = tempPathVariables.entrySet().iterator(); current
                     .hasNext();) {
                 Map.Entry entry = (Map.Entry) current.next();
                 String variableName = (String) entry.getKey();
                 IPath variableValue = (IPath) entry.getValue();
                 pathVariableManager.setValue(variableName, variableValue);
             }
             // re-initialize temporary state
             initTemporaryState();

             // performOk accepted
             return true;
         } catch (CoreException ce) {
             ErrorDialog.openError(shell, null, null, ce.getStatus());
         }
         return false;
     }

     /**
      * Removes the currently selected variables.
      */
     private void removeSelectedVariables() {
         // remove each selected element
         int[] selectedIndices = variableTable.getSelectionIndices();
         for (int i = 0; i < selectedIndices.length; i++) {
             TableItem selectedItem = variableTable.getItem(selectedIndices[i]);
             String varName = (String) selectedItem.getData();
             removedVariableNames.add(varName);
             tempPathVariables.remove(varName);
         }
         updateWidgetState(null);
     }

     /**
      * Sets the <code>GridData</code> on the specified button to
      * be one that is spaced for the current dialog page units. The
      * method <code>initializeDialogUnits</code> must be called once
      * before calling this method for the first time.
      *
      * @param button the button to set the <code>GridData</code>
      * @return the <code>GridData</code> set on the specified button
      */
     private GridData setButtonLayoutData(Button button) {
         GridData data = new GridData(GridData.HORIZONTAL_ALIGN_FILL);
         int widthHint = Dialog.convertHorizontalDLUsToPixels(fontMetrics,
                 IDialogConstants.BUTTON_WIDTH);
         data.widthHint = Math.max(widthHint, button.computeSize(SWT.DEFAULT,
                 SWT.DEFAULT, true).x);
         button.setLayoutData(data);
         return data;
     }

     /**
      * Sets the enabled state of the group's widgets.
      * Does nothing if called prior to calling <code>createContents</code>.
      *
      * @param enabled the new enabled state of the group's widgets
      */
     public void setEnabled(boolean enabled) {
         if (variableTable != null && !variableTable.isDisposed()) {
             variableLabel.setEnabled(enabled);
             variableTable.setEnabled(enabled);
             addButton.setEnabled(enabled);
             if (enabled)
                 updateEnabledState();
             else {
                 editButton.setEnabled(enabled);
                 removeButton.setEnabled(enabled);
             }
         }
     }

     /**
      * Updates the widget's current state: refreshes the table with the current
      * defined variables, selects the item corresponding to the given variable
      * (selects the first item if <code>null</code> is provided) and updates
      * the enabled state for the Add/Remove/Edit buttons.
      *
      * @param selectedVarName the name of the variable to be selected (may be null)
      */
     private void updateWidgetState(String selectedVarName) {
         updateVariableTable(selectedVarName);
         updateEnabledState();
     }
 }
	/*******************************************************************************
	* Copyright (c) 2000, 2005 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
	*******************************************************************************/
	package org.eclipse.ui.internal.ide.dialogs;

	import java.util.HashSet;
	import java.util.Iterator;
	import java.util.Map;
	import java.util.Set;
	import java.util.SortedMap;
	import java.util.TreeMap;

	import org.eclipse.core.filesystem.IFileInfo;
	import org.eclipse.core.resources.IPathVariableManager;
	import org.eclipse.core.resources.IResource;
	import org.eclipse.core.resources.ResourcesPlugin;
	import org.eclipse.core.runtime.CoreException;
	import org.eclipse.core.runtime.IPath;
	import org.eclipse.core.runtime.Path;
	import org.eclipse.jface.dialogs.Dialog;
	import org.eclipse.jface.dialogs.ErrorDialog;
	import org.eclipse.jface.dialogs.IDialogConstants;
	import org.eclipse.jface.resource.ImageDescriptor;
	import org.eclipse.jface.window.Window;
	import org.eclipse.swt.SWT;
	import org.eclipse.swt.events.SelectionAdapter;
	import org.eclipse.swt.events.SelectionEvent;
	import org.eclipse.swt.graphics.Font;
	import org.eclipse.swt.graphics.FontMetrics;
	import org.eclipse.swt.graphics.GC;
	import org.eclipse.swt.graphics.Image;
	import org.eclipse.swt.layout.GridData;
	import org.eclipse.swt.layout.GridLayout;
	import org.eclipse.swt.widgets.Button;
	import org.eclipse.swt.widgets.Composite;
	import org.eclipse.swt.widgets.Control;
	import org.eclipse.swt.widgets.Event;
	import org.eclipse.swt.widgets.Label;
	import org.eclipse.swt.widgets.Listener;
	import org.eclipse.swt.widgets.Shell;
	import org.eclipse.swt.widgets.Table;
	import org.eclipse.swt.widgets.TableItem;
	import org.eclipse.ui.ISharedImages;
	import org.eclipse.ui.PlatformUI;
	import org.eclipse.ui.internal.ide.IDEWorkbenchMessages;
	import org.eclipse.ui.internal.ide.IDEWorkbenchPlugin;
	import org.eclipse.ui.plugin.AbstractUIPlugin;

	/**
	* A widget group that displays path variables.
	* Includes buttons to edit, remove existing variables and create new ones.
	*
	* @since 2.1
	*/
	public class PathVariablesGroup {
	/**
	* Simple data structure that holds a path variable name/value pair.
	*/
	public static class PathVariableElement {
	/**
	* The name of the element.
	*/
	public String name;

	/**
	* The path of the element.
	*/
	public IPath path;
	}

	// sizing constants
	private static final int SIZING_SELECTION_PANE_WIDTH = 400;

	// parent shell
	private Shell shell;

	private Label variableLabel;

	private Table variableTable;

	private Button addButton;

	private Button editButton;

	private Button removeButton;

	// used to compute layout sizes
	private FontMetrics fontMetrics;

	// create a multi select table
	private boolean multiSelect;

	// IResource.FILE and/or IResource.FOLDER
	private int variableType;

	// External listener called when the table selection changes
	private Listener selectionListener;

	// temporary collection for keeping currently defined variables
	private SortedMap tempPathVariables;

	// set of removed variables' names
	private Set removedVariableNames;

	// reference to the workspace's path variable manager
	private IPathVariableManager pathVariableManager;

	// file image
	private final Image FILE_IMG = PlatformUI.getWorkbench().getSharedImages()
	.getImage(ISharedImages.IMG_OBJ_FILE);

	// folder image
	private final Image FOLDER_IMG = PlatformUI.getWorkbench()
	.getSharedImages().getImage(ISharedImages.IMG_OBJ_FOLDER);

	// unknown (non-existent) image. created locally, dispose locally
	private Image imageUnkown;

	/**
	* Creates a new PathVariablesGroup.
	*
	* @param multiSelect create a multi select tree
	* @param variableType the type of variables that are displayed in
	* the widget group. <code>IResource.FILE</code> and/or <code>IResource.FOLDER</code>
	* logically ORed together.
	*/
	public PathVariablesGroup(boolean multiSelect, int variableType) {
	this.multiSelect = multiSelect;
	this.variableType = variableType;
	pathVariableManager = ResourcesPlugin.getWorkspace()
	.getPathVariableManager();
	removedVariableNames = new HashSet();
	tempPathVariables = new TreeMap();
	// initialize internal model
	initTemporaryState();
	}

	/**
	* Creates a new PathVariablesGroup.
	*
	* @param multiSelect create a multi select tree
	* @param variableType the type of variables that are displayed in
	* the widget group. <code>IResource.FILE</code> and/or <code>IResource.FOLDER</code>
	* logically ORed together.
	* @param selectionListener listener notified when the selection changes
	* in the variables list.
	*/
	public PathVariablesGroup(boolean multiSelect, int variableType,
	Listener selectionListener) {
	this(multiSelect, variableType);
	this.selectionListener = selectionListener;
	}

	/**
	* Opens a dialog for creating a new variable.
	*/
	private void addNewVariable() {
	// constructs a dialog for editing the new variable's current name and value
	PathVariableDialog dialog = new PathVariableDialog(shell,
	PathVariableDialog.NEW_VARIABLE, variableType,
	pathVariableManager, tempPathVariables.keySet());

	// opens the dialog - just returns if the user cancels it
	if (dialog.open() == Window.CANCEL)
	return;

	// otherwise, adds the new variable (or updates an existing one) in the
	// temporary collection of currently defined variables
	String newVariableName = dialog.getVariableName();
	IPath newVariableValue = new Path(dialog.getVariableValue());
	tempPathVariables.put(newVariableName, newVariableValue);

	// the UI must be updated
	updateWidgetState(newVariableName);
	}

	/**
	* Creates the widget group.
	* Callers must call <code>dispose</code> when the group is no
	* longer needed.
	*
	* @param parent the widget parent
	* @return container of the widgets
	*/
	public Control createContents(Composite parent) {
	Font font = parent.getFont();

	if (imageUnkown == null) {
	ImageDescriptor descriptor = AbstractUIPlugin
	.imageDescriptorFromPlugin(
	IDEWorkbenchPlugin.IDE_WORKBENCH,
	"$nl$/icons/full/obj16/warning.gif"); //$NON-NLS-1$
	imageUnkown = descriptor.createImage();
	}
	initializeDialogUnits(parent);
	shell = parent.getShell();

	// define container & its layout
	Composite pageComponent = new Composite(parent, SWT.NULL);
	GridLayout layout = new GridLayout();
	layout.numColumns = 2;
	layout.marginWidth = 0;
	layout.marginHeight = 0;
	pageComponent.setLayout(layout);
	GridData data = new GridData(GridData.FILL_BOTH);
	data.widthHint = SIZING_SELECTION_PANE_WIDTH;
	pageComponent.setLayoutData(data);
	pageComponent.setFont(font);

	// layout the table & its buttons
	variableLabel = new Label(pageComponent, SWT.LEFT);
	variableLabel.setText(IDEWorkbenchMessages.PathVariablesBlock_variablesLabel);
	data = new GridData();
	data.horizontalAlignment = GridData.FILL;
	data.horizontalSpan = 2;
	variableLabel.setLayoutData(data);
	variableLabel.setFont(font);

	int tableStyle = SWT.BORDER \| SWT.FULL_SELECTION;
	if (multiSelect) {
	tableStyle \|= SWT.MULTI;
	}
	variableTable = new Table(pageComponent, tableStyle);
	variableTable.addSelectionListener(new SelectionAdapter() {
	public void widgetSelected(SelectionEvent e) {
	updateEnabledState();
	if (selectionListener != null)
	selectionListener.handleEvent(new Event());
	}
	});
	data = new GridData(GridData.FILL_BOTH);
	data.heightHint = variableTable.getItemHeight() * 7;
	variableTable.setLayoutData(data);
	variableTable.setFont(font);

	createButtonGroup(pageComponent);
	// populate table with current internal state and set buttons' initial state
	updateWidgetState(null);

	return pageComponent;
	}

	/**
	* Disposes the group's resources.
	*/
	public void dispose() {
	if (imageUnkown != null) {
	imageUnkown.dispose();
	imageUnkown = null;
	}
	}

	/**
	* Opens a dialog for editing an existing variable.
	*
	* @see PathVariableDialog
	*/
	private void editSelectedVariable() {
	// retrieves the name and value for the currently selected variable
	TableItem item = variableTable.getItem(variableTable
	.getSelectionIndex());
	String variableName = (String) item.getData();
	IPath variableValue = (IPath) tempPathVariables.get(variableName);

	// constructs a dialog for editing the variable's current name and value
	PathVariableDialog dialog = new PathVariableDialog(shell,
	PathVariableDialog.EXISTING_VARIABLE, variableType,
	pathVariableManager, tempPathVariables.keySet());
	dialog.setVariableName(variableName);
	dialog.setVariableValue(variableValue.toOSString());

	// opens the dialog - just returns if the user cancels it
	if (dialog.open() == Window.CANCEL)
	return;

	// the name can be changed, so we remove the current variable definition...
	removedVariableNames.add(variableName);
	tempPathVariables.remove(variableName);

	String newVariableName = dialog.getVariableName();
	IPath newVariableValue = new Path(dialog.getVariableValue());

	// and add it again (maybe with a different name)
	tempPathVariables.put(newVariableName, newVariableValue);

	// now we must refresh the UI state
	updateWidgetState(newVariableName);

	}

	/**
	* Returns the enabled state of the group's widgets.
	* Returns <code>true</code> if called prior to calling
	* <code>createContents</code>.
	*
	* @return boolean the enabled state of the group's widgets.
	* <code>true</code> if called prior to calling <code>createContents</code>.
	*/
	public boolean getEnabled() {
	if (variableTable != null && !variableTable.isDisposed()) {
	return variableTable.getEnabled();
	}
	return true;
	}

	/**
	* Returns the selected variables.
	*
	* @return the selected variables. Returns an empty array if
	* the widget group has not been created yet by calling
	* <code>createContents</code>
	*/
	public PathVariableElement[] getSelection() {
	if (variableTable == null) {
	return new PathVariableElement[0];
	}
	TableItem[] items = variableTable.getSelection();
	PathVariableElement[] selection = new PathVariableElement[items.length];

	for (int i = 0; i < items.length; i++) {
	String name = (String) items[i].getData();
	selection[i] = new PathVariableElement();
	selection[i].name = name;
	selection[i].path = (IPath) tempPathVariables.get(name);
	}
	return selection;
	}

	/**
	* Creates the add/edit/remove buttons
	*
	* @param parent the widget parent
	*/
	private void createButtonGroup(Composite parent) {
	Font font = parent.getFont();
	Composite groupComponent = new Composite(parent, SWT.NULL);
	GridLayout groupLayout = new GridLayout();
	groupLayout.marginWidth = 0;
	groupLayout.marginHeight = 0;
	groupComponent.setLayout(groupLayout);
	GridData data = new GridData();
	data.verticalAlignment = GridData.FILL;
	data.horizontalAlignment = GridData.FILL;
	groupComponent.setLayoutData(data);
	groupComponent.setFont(font);

	addButton = new Button(groupComponent, SWT.PUSH);
	addButton.setText(IDEWorkbenchMessages.PathVariablesBlock_addVariableButton);
	addButton.addSelectionListener(new SelectionAdapter() {
	public void widgetSelected(SelectionEvent e) {
	addNewVariable();
	}
	});
	addButton.setFont(font);
	setButtonLayoutData(addButton);

	editButton = new Button(groupComponent, SWT.PUSH);
	editButton.setText(IDEWorkbenchMessages.PathVariablesBlock_editVariableButton);
	editButton.addSelectionListener(new SelectionAdapter() {
	public void widgetSelected(SelectionEvent e) {
	editSelectedVariable();
	}
	});
	editButton.setFont(font);
	setButtonLayoutData(editButton);

	removeButton = new Button(groupComponent, SWT.PUSH);
	removeButton.setText(IDEWorkbenchMessages.PathVariablesBlock_removeVariableButton);
	removeButton.addSelectionListener(new SelectionAdapter() {
	public void widgetSelected(SelectionEvent e) {
	removeSelectedVariables();
	}
	});
	removeButton.setFont(font);
	setButtonLayoutData(removeButton);
	}

	/**
	* Initializes the computation of horizontal and vertical dialog units
	* based on the size of current font.
	* <p>
	* This method must be called before <code>setButtonLayoutData</code>
	* is called.
	* </p>
	*
	* @param control a control from which to obtain the current font
	*/
	protected void initializeDialogUnits(Control control) {
	// Compute and store a font metric
	GC gc = new GC(control);
	gc.setFont(control.getFont());
	fontMetrics = gc.getFontMetrics();
	gc.dispose();
	}

	/**
	* (Re-)Initialize collections used to mantain temporary variable state.
	*/
	private void initTemporaryState() {
	String[] varNames = pathVariableManager.getPathVariableNames();

	tempPathVariables.clear();
	for (int i = 0; i < varNames.length; i++) {
	IPath value = pathVariableManager.getValue(varNames[i]);

	// the value may not exist any more
	if (value != null) {
	boolean isFile = value.toFile().isFile();
	if ((isFile && (variableType & IResource.FILE) != 0)
	\|\| (isFile == false && (variableType & IResource.FOLDER) != 0)) {

	tempPathVariables.put(varNames[i], value);
	}
	}
	}
	removedVariableNames.clear();
	}

	/**
	* Updates button enabled state, depending on the number of currently selected
	* variables in the table.
	*/
	private void updateEnabledState() {
	int itemsSelectedCount = variableTable.getSelectionCount();
	editButton.setEnabled(itemsSelectedCount == 1);
	removeButton.setEnabled(itemsSelectedCount > 0);
	}

	/**
	* Rebuilds table widget state with the current list of variables (reflecting
	* any changes, additions and removals), and selects the item corresponding to
	* the given variable name. If the variable name is <code>null</code>, the
	* first item (if any) will be selected.
	*
	* @param selectedVarName the name for the variable to be selected (may be
	* <code>null</code>)
	* @see IPathVariableManager#getPathVariableNames()
	* @see IPathVariableManager#getValue(String)
	*/
	private void updateVariableTable(String selectedVarName) {
	variableTable.removeAll();
	int selectedVarIndex = 0;
	for (Iterator varNames = tempPathVariables.keySet().iterator(); varNames
	.hasNext();) {
	TableItem item = new TableItem(variableTable, SWT.NONE);
	String varName = (String) varNames.next();
	IPath value = (IPath) tempPathVariables.get(varName);
	IFileInfo file = IDEResourceInfoUtils.getFileInfo(value);

	item.setText(varName + " - " + value.toOSString()); //$NON-NLS-1$
	// the corresponding variable name is stored in each table widget item
	item.setData(varName);
	item.setImage(file.exists() ? (file.isDirectory() ? FOLDER_IMG
	: FILE_IMG ) : imageUnkown);
	if (varName.equals(selectedVarName))
	selectedVarIndex = variableTable.getItemCount() - 1;
	}
	if (variableTable.getItemCount() > selectedVarIndex) {
	variableTable.setSelection(selectedVarIndex);
	if (selectionListener != null)
	selectionListener.handleEvent(new Event());
	} else if (variableTable.getItemCount() == 0
	&& selectionListener != null)
	selectionListener.handleEvent(new Event());
	}

	/**
	* Commits the temporary state to the path variable manager in response to user
	* confirmation.
	* @return boolean <code>true</code> if there were no problems.
	* @see IPathVariableManager#setValue(String, IPath)
	*/
	public boolean performOk() {
	try {
	// first process removed variables
	for (Iterator removed = removedVariableNames.iterator(); removed
	.hasNext();) {
	String removedVariableName = (String) removed.next();
	// only removes variables that have not been added again
	if (!tempPathVariables.containsKey(removedVariableName))
	pathVariableManager.setValue(removedVariableName, null);
	}

	// then process the current collection of variables, adding/updating them
	for (Iterator current = tempPathVariables.entrySet().iterator(); current
	.hasNext();) {
	Map.Entry entry = (Map.Entry) current.next();
	String variableName = (String) entry.getKey();
	IPath variableValue = (IPath) entry.getValue();
	pathVariableManager.setValue(variableName, variableValue);
	}
	// re-initialize temporary state
	initTemporaryState();

	// performOk accepted
	return true;
	} catch (CoreException ce) {
	ErrorDialog.openError(shell, null, null, ce.getStatus());
	}
	return false;
	}

	/**
	* Removes the currently selected variables.
	*/
	private void removeSelectedVariables() {
	// remove each selected element
	int[] selectedIndices = variableTable.getSelectionIndices();
	for (int i = 0; i < selectedIndices.length; i++) {
	TableItem selectedItem = variableTable.getItem(selectedIndices[i]);
	String varName = (String) selectedItem.getData();
	removedVariableNames.add(varName);
	tempPathVariables.remove(varName);
	}
	updateWidgetState(null);
	}

	/**
	* Sets the <code>GridData</code> on the specified button to
	* be one that is spaced for the current dialog page units. The
	* method <code>initializeDialogUnits</code> must be called once
	* before calling this method for the first time.
	*
	* @param button the button to set the <code>GridData</code>
	* @return the <code>GridData</code> set on the specified button
	*/
	private GridData setButtonLayoutData(Button button) {
	GridData data = new GridData(GridData.HORIZONTAL_ALIGN_FILL);
	int widthHint = Dialog.convertHorizontalDLUsToPixels(fontMetrics,
	IDialogConstants.BUTTON_WIDTH);
	data.widthHint = Math.max(widthHint, button.computeSize(SWT.DEFAULT,
	SWT.DEFAULT, true).x);
	button.setLayoutData(data);
	return data;
	}

	/**
	* Sets the enabled state of the group's widgets.
	* Does nothing if called prior to calling <code>createContents</code>.
	*
	* @param enabled the new enabled state of the group's widgets
	*/
	public void setEnabled(boolean enabled) {
	if (variableTable != null && !variableTable.isDisposed()) {
	variableLabel.setEnabled(enabled);
	variableTable.setEnabled(enabled);
	addButton.setEnabled(enabled);
	if (enabled)
	updateEnabledState();
	else {
	editButton.setEnabled(enabled);
	removeButton.setEnabled(enabled);
	}
	}
	}

	/**
	* Updates the widget's current state: refreshes the table with the current
	* defined variables, selects the item corresponding to the given variable
	* (selects the first item if <code>null</code> is provided) and updates
	* the enabled state for the Add/Remove/Edit buttons.
	*
	* @param selectedVarName the name of the variable to be selected (may be null)
	*/
	private void updateWidgetState(String selectedVarName) {
	updateVariableTable(selectedVarName);
	updateEnabledState();
	}
	}