### Eclipse Workspace Patch 1.0
#P org.eclipse.jface
Index: src/org/eclipse/jface/dialogs/TitleAreaDialog.java
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.jface/src/org/eclipse/jface/dialogs/TitleAreaDialog.java,v
retrieving revision 1.44
diff -u -r1.44 TitleAreaDialog.java
--- src/org/eclipse/jface/dialogs/TitleAreaDialog.java	23 Oct 2008 18:51:06 -0000	1.44
+++ src/org/eclipse/jface/dialogs/TitleAreaDialog.java	20 Apr 2009 22:48:01 -0000
@@ -28,6 +28,7 @@
 import org.eclipse.swt.layout.FormLayout;
 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.Display;
@@ -89,8 +90,12 @@
 	private RGB titleAreaRGB;
 
 	Color titleAreaColor;
+	
+	private String description = ""; //$NON-NLS-1$
 
-	private String message = ""; //$NON-NLS-1$
+	private String message;
+	
+	private int messageType = IMessageProvider.NONE;
 
 	private String errorMessage;
 
@@ -103,8 +108,12 @@
 	private Image messageImage;
 
 	private boolean showingError = false;
+	
+	private boolean showingMessage = false;
 
 	private boolean titleImageLargest = true;
+	
+	private boolean dialogComplete = true;
 
 	private int messageLabelHeight;
 
@@ -372,16 +381,20 @@
 				// we were previously showing an error
 				showingError = false;
 			}
-			// show the message
-			// avoid calling setMessage in case it is overridden to call
+			// show the description or message
+			// avoid calling setDescription or setMessage in case it is overridden to call
 			// setErrorMessage,
 			// which would result in a recursive infinite loop
-			if (message == null) // this should probably never happen since
-				// setMessage does this conversion....
-				message = ""; //$NON-NLS-1$
-			updateMessage(message);
-			messageImageLabel.setImage(messageImage);
-			setImageLabelVisible(messageImage != null);
+			if (showingMessage) {
+				updateMessage(message);
+				messageImageLabel.setImage(messageImage);
+				setImageLabelVisible(messageImage != null);
+			}
+			else {
+				updateMessage(description);
+				messageImageLabel.setImage(null);
+				setImageLabelVisible(false);
+			}
 		} else {
 			// Add in a space for layout purposes but do not
 			// change the instance variable
@@ -492,6 +505,7 @@
 	 */
 	public void setMessage(String newMessage, int newType) {
 		Image newImage = null;
+		messageType = newType;
 		if (newMessage != null) {
 			switch (newType) {
 			case IMessageProvider.NONE:
@@ -518,23 +532,34 @@
 	 */
 	private void showMessage(String newMessage, Image newImage) {
 		// Any change?
-		if (message.equals(newMessage) && messageImage == newImage) {
+		if ((message == null ? newMessage == null : message
+				.equals(newMessage)) && messageImage == newImage) {
 			return;
 		}
 		message = newMessage;
-		if (message == null)
-			message = "";//$NON-NLS-1$
-		// Message string to be shown - if there is an image then add in
-		// a space to the message for layout purposes
-		String shownMessage = (newImage == null) ? message : " " + message; //$NON-NLS-1$  
 		messageImage = newImage;
-		if (!showingError) {
-			// we are not showing an error
-			updateMessage(shownMessage);
-			messageImageLabel.setImage(messageImage);
-			setImageLabelVisible(messageImage != null);
-			layoutForNewMessage();
+		
+		if (message == null) {
+			if (showingMessage)
+				showingMessage = false;
+			if (!showingError) {
+				updateMessage(description);
+			}
 		}
+		else {
+			if (!showingMessage)
+				showingMessage = true;
+			// Message string to be shown - if there is an image then add in
+			// a space to the message for layout purposes
+			String shownMessage = (newImage == null) ? message : " " + message; //$NON-NLS-1$  
+			if (!showingError) {
+				// we are not showing an error
+				updateMessage(shownMessage);
+			}
+		}
+		messageImageLabel.setImage(messageImage);
+		setImageLabelVisible(messageImage != null);
+		layoutForNewMessage();
 	}
 
 	/**
@@ -621,4 +646,95 @@
 		childData.bottom = new FormAttachment(100, 0);
 		workArea.setLayoutData(childData);
 	}
+	
+	protected Control createButtonBar(Composite parent) {
+		Control control = super.createButtonBar(parent);
+		Button okButton = getButton(IDialogConstants.OK_ID);
+		if (okButton != null) {
+			okButton.setEnabled(dialogComplete);
+		}
+		return control;
+	}
+	
+	/**
+	 * Sets whether this dialog is complete.
+	 * @param complete 
+	 *             true if this dialog is complete, and and false otherwise
+	 */
+	public void setDialogComplete(boolean complete) {
+		Button okButton = getButton(IDialogConstants.OK_ID);
+		if (okButton != null)
+			okButton.setEnabled(complete);
+		dialogComplete = complete;
+	}
+	
+	/**
+	 * Returns the value of an internal state variable set by setPageComplete. 
+	 * @return true if this dialog is complete, and false otherwise
+	 */
+	public boolean isDialogComplete() {
+		return dialogComplete;
+	}
+	
+	/**
+	 * Sets this dialog description text.
+	 * @param description 
+	 *               the description text for this dialog page, or null if none
+	 */
+	public void setDescription(String description) {
+		showDescription(description);
+	}
+	
+	private void showDescription(String newDescription) {
+		// Any change?
+		if (description.equals(newDescription)) {
+			return;
+		}
+		description = newDescription;
+		if (description == null) {
+			description = ""; //$NON-NLS-1$
+		}
+		
+		if (!showingError && !showingMessage) {
+			updateMessage(description);
+			messageImageLabel.setImage(null);
+			setImageLabelVisible(false);
+			layoutForNewMessage();
+		}
+	}
+	
+	/**
+	 * Returns this dialog description text.
+	 * @return the description text for this dialog, or null if none
+	 */
+	public String getDescription() {
+		return description;
+	}
+	
+	/**
+	 * Returns the current message for this dialog.
+	 * A message provides instruction or information to the user, as opposed to an error message which should describe some error state.
+	 * @return the message, or null if none
+	 */
+	public String getMessage() {
+		return message;
+	}
+	
+	/**
+	 * Returns a value indicating if the message is a an information message, a warning message, or an error message.
+	 * Returns one of NONE,INFORMATION, WARNING, or ERROR.
+	 * @return the message type
+	 */
+	public int getMessageType() {
+		return messageType;
+	}
+	
+	/**
+	 * Returns the current error message for this dialog. May be null to indicate no error message.
+	 * An error message should describe some error state, as opposed to a message which may simply provide instruction or information to the user.
+	 * @return the error message, or null if none
+	 */
+	public String getErrorMessage() {
+		return errorMessage;
+	}
 }
#P org.eclipse.jface.databinding
Index: src/org/eclipse/jface/databinding/dialog/TitleAreaDialogSupport.java
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.jface.databinding/src/org/eclipse/jface/databinding/dialog/TitleAreaDialogSupport.java,v
retrieving revision 1.2
diff -u -r1.2 TitleAreaDialogSupport.java
--- src/org/eclipse/jface/databinding/dialog/TitleAreaDialogSupport.java	3 Feb 2009 03:04:19 -0000	1.2
+++ src/org/eclipse/jface/databinding/dialog/TitleAreaDialogSupport.java	20 Apr 2009 22:48:02 -0000
@@ -37,6 +37,8 @@
 import org.eclipse.core.runtime.Status;
 import org.eclipse.jface.dialogs.IMessageProvider;
 import org.eclipse.jface.dialogs.TitleAreaDialog;
+import org.eclipse.swt.events.DisposeEvent;
+import org.eclipse.swt.events.DisposeListener;
 
 /**
  * Connects the validation result from the given data binding context to the
@@ -116,9 +118,9 @@
 	};
 	private IStatus currentStatus;
 
-	private TitleAreaDialogSupport(TitleAreaDialog dialogPage,
+	private TitleAreaDialogSupport(TitleAreaDialog dialog,
 			DataBindingContext dbc) {
-		this.dialog = dialogPage;
+		this.dialog = dialog;
 		this.dbc = dbc;
 		init();
 	}
@@ -127,12 +129,18 @@
 		aggregateStatus = new AggregateValidationStatus(dbc
 				.getValidationStatusProviders(),
 				AggregateValidationStatus.MAX_SEVERITY);
-		aggregateStatus.addValueChangeListener(new IValueChangeListener() {
+		final IValueChangeListener changeListener = new IValueChangeListener() {
 			public void handleValueChange(ValueChangeEvent event) {
 
 				currentStatus = (IStatus) event.diff.getNewValue();
 				handleStatusChanged();
 			}
+		};
+		aggregateStatus.addValueChangeListener(changeListener);
+		dialog.getShell().addDisposeListener(new DisposeListener() {
+			public void widgetDisposed(DisposeEvent e) {
+				aggregateStatus.removeValueChangeListener(changeListener);
+			}
 		});
 		currentStatus = (IStatus) aggregateStatus.getValue();
 		handleStatusChanged();
@@ -213,6 +221,13 @@
 			dialog.setMessage(null);
 			dialog.setErrorMessage(null);
 		}
+
+		boolean pageComplete = true;
+		if (currentStatus != null) {
+			pageComplete = !currentStatus.matches(IStatus.ERROR
+					| IStatus.CANCEL);
+		}
+		dialog.setDialogComplete(pageComplete);
 	}
 
 	private boolean currentStatusHasException() {