bundles/org.eclipse.jface/src/org/eclipse/jface/preference/PreferencePage.java - platform/eclipse.platform.ui - Git at Google

 /*******************************************************************************
  * Copyright (c) 2000, 2007 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
  * 	   Sebastian Davids <sdavids@gmx.de> - Fix for bug 38729 - [Preferences]
  * 			 NPE PreferencePage isValid.
  *******************************************************************************/
 package org.eclipse.jface.preference;

 import org.eclipse.jface.dialogs.Dialog;
 import org.eclipse.jface.dialogs.DialogPage;
 import org.eclipse.jface.dialogs.IDialogConstants;
 import org.eclipse.jface.dialogs.IDialogPage;
 import org.eclipse.jface.resource.ImageDescriptor;
 import org.eclipse.jface.resource.JFaceResources;
 import org.eclipse.jface.util.IPropertyChangeListener;
 import org.eclipse.jface.util.PropertyChangeEvent;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.events.DisposeEvent;
 import org.eclipse.swt.events.DisposeListener;
 import org.eclipse.swt.events.SelectionAdapter;
 import org.eclipse.swt.events.SelectionEvent;
 import org.eclipse.swt.graphics.Font;
 import org.eclipse.swt.graphics.Point;
 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;

 /**
  * Abstract base implementation for all preference page implementations.
  * <p>
  * Subclasses must implement the <code>createControl</code> framework
  * method to supply the page's main control.
  * </p>
  * <p>
  * Subclasses should extend the <code>doComputeSize</code> framework
  * method to compute the size of the page's control.
  * </p>
  * <p>
  * Subclasses may override the <code>performOk</code>, <code>performApply</code>,
  * <code>performDefaults</code>, <code>performCancel</code>, and <code>performHelp</code>
  * framework methods to react to the standard button events.
  * </p>
  * <p>
  * Subclasses may call the <code>noDefaultAndApplyButton</code> framework
  * method before the page's control has been created to suppress
  * the standard Apply and Defaults buttons.
  * </p>
  */
 public abstract class PreferencePage extends DialogPage implements
         IPreferencePage {

     /**
      * Preference store, or <code>null</code>.
      */
     private IPreferenceStore preferenceStore;

     /**
      * Valid state for this page; <code>true</code> by default.
      *
      * @see #isValid
      */
     private boolean isValid = true;

     /**
      * Body of page.
      */
     private Control body;

     /**
      * Whether this page has the standard Apply and Defaults buttons;
      * <code>true</code> by default.
      *
      * @see #noDefaultAndApplyButton
      */
     private boolean createDefaultAndApplyButton = true;

     /**
      * Standard Defaults button, or <code>null</code> if none.
      * This button has id <code>DEFAULTS_ID</code>.
      */
     private Button defaultsButton = null;

     /**
      * The container this preference page belongs to; <code>null</code>
      * if none.
      */
     private IPreferencePageContainer container = null;

     /**
      * Standard Apply button, or <code>null</code> if none.
      * This button has id <code>APPLY_ID</code>.
      */
     private Button applyButton = null;

     /**
      * Description label.
      *
      * @see #createDescriptionLabel(Composite)
      */
     private Label descriptionLabel;

     /**
      * Caches size of page.
      */
     private Point size = null;


     /**
      * Creates a new preference page with an empty title and no image.
      */
     protected PreferencePage() {
         this(""); //$NON-NLS-1$
     }

     /**
      * Creates a new preference page with the given title and no image.
      *
      * @param title the title of this preference page
      */
     protected PreferencePage(String title) {
         super(title);
     }

     /**
      * Creates a new abstract preference page with the given title and image.
      *
      * @param title the title of this preference page
      * @param image the image for this preference page,
      *  or <code>null</code> if none
      */
     protected PreferencePage(String title, ImageDescriptor image) {
         super(title, image);
     }

     /**
      * Computes the size for this page's UI control.
      * <p>
      * The default implementation of this <code>IPreferencePage</code>
      * method returns the size set by <code>setSize</code>; if no size
      * has been set, but the page has a UI control, the framework
      * method <code>doComputeSize</code> is called to compute the size.
      * </p>
      *
      * @return the size of the preference page encoded as
      *   <code>new Point(width,height)</code>, or
      *   <code>(0,0)</code> if the page doesn't currently have any UI component
      */
     public Point computeSize() {
         if (size != null) {
 			return size;
 		}
         Control control = getControl();
         if (control != null) {
             size = doComputeSize();
             return size;
         }
         return new Point(0, 0);
     }

     /**
      * Contributes additional buttons to the given composite.
      * <p>
      * The default implementation of this framework hook method does
      * nothing. Subclasses should override this method to contribute buttons
      * to this page's button bar. For each button a subclass contributes,
      * it must also increase the parent's grid layout number of columns
      * by one; that is,
      * <pre>
      * ((GridLayout) parent.getLayout()).numColumns++);
      * </pre>
      * </p>
      *
      * @param parent the button bar
      */
     protected void contributeButtons(Composite parent) {
     }

     /**
      * Creates and returns the SWT control for the customized body
      * of this preference page under the given parent composite.
      * <p>
      * This framework method must be implemented by concrete subclasses. Any
      * subclass returning a <code>Composite</code> object whose <code>Layout</code>
      * has default margins (for example, a <code>GridLayout</code>) are expected to
      * set the margins of this <code>Layout</code> to 0 pixels.
      * </p>
      *
      * @param parent the parent composite
      * @return the new control
      */
     protected abstract Control createContents(Composite parent);

     /**
      * The <code>PreferencePage</code> implementation of this
      * <code>IDialogPage</code> method creates a description label
      * and button bar for the page. It calls <code>createContents</code>
      * to create the custom contents of the page.
      * <p>
      * If a subclass that overrides this method creates a <code>Composite</code>
      * that has a layout with default margins (for example, a <code>GridLayout</code>)
      * it is expected to set the margins of this <code>Layout</code> to 0 pixels.
      * @see IDialogPage#createControl(Composite)
      */
     public void createControl(Composite parent){

         GridData gd;
         Composite content = new Composite(parent, SWT.NONE);
         setControl(content);
         GridLayout layout = new GridLayout();
         layout.marginWidth = 0;
         layout.marginHeight = 0;
         content.setLayout(layout);
         //Apply the font on creation for backward compatibility
         applyDialogFont(content);

         // initialize the dialog units
         initializeDialogUnits(content);

         descriptionLabel = createDescriptionLabel(content);
         if (descriptionLabel != null) {
             descriptionLabel.setLayoutData(new GridData(
                     GridData.FILL_HORIZONTAL));
         }

         body = createContents(content);
         if (body != null) {
 			// null is not a valid return value but support graceful failure
             body.setLayoutData(new GridData(GridData.FILL_BOTH));
 		}

         Composite buttonBar = new Composite(content, SWT.NONE);
         layout = new GridLayout();
         layout.numColumns = 0;
         layout.marginHeight = 0;
         layout.marginWidth = 0;
         layout.makeColumnsEqualWidth = false;
         buttonBar.setLayout(layout);

         gd = new GridData(GridData.HORIZONTAL_ALIGN_END);

         buttonBar.setLayoutData(gd);

         contributeButtons(buttonBar);

         if (createDefaultAndApplyButton) {
             layout.numColumns = layout.numColumns + 2;
 			String[] labels = JFaceResources.getStrings(new String[] {
 					"defaults", "apply" }); //$NON-NLS-2$//$NON-NLS-1$
 			int widthHint = convertHorizontalDLUsToPixels(IDialogConstants.BUTTON_WIDTH);
 			defaultsButton = new Button(buttonBar, SWT.PUSH);
 			defaultsButton.setText(labels[0]);
 			Dialog.applyDialogFont(defaultsButton);
 			GridData data = new GridData(GridData.HORIZONTAL_ALIGN_FILL);
 			Point minButtonSize = defaultsButton.computeSize(SWT.DEFAULT,
 					SWT.DEFAULT, true);
 			data.widthHint = Math.max(widthHint, minButtonSize.x);
 			defaultsButton.setLayoutData(data);
 			defaultsButton.addSelectionListener(new SelectionAdapter() {
 				public void widgetSelected(SelectionEvent e) {
 					performDefaults();
 				}
 			});

             applyButton = new Button(buttonBar, SWT.PUSH);
 			applyButton.setText(labels[1]);
 			Dialog.applyDialogFont(applyButton);
 			data = new GridData(GridData.HORIZONTAL_ALIGN_FILL);
 			minButtonSize = applyButton.computeSize(SWT.DEFAULT, SWT.DEFAULT,
 					true);
 			data.widthHint = Math.max(widthHint, minButtonSize.x);
 			applyButton.setLayoutData(data);
 			applyButton.addSelectionListener(new SelectionAdapter() {
 				public void widgetSelected(SelectionEvent e) {
 					performApply();
 				}
 			});
             applyButton.setEnabled(isValid());
             applyDialogFont(buttonBar);
         } else {
             /* Check if there are any other buttons on the button bar.
              * If not, throw away the button bar composite.  Otherwise
              * there is an unusually large button bar.
              */
             if (buttonBar.getChildren().length < 1) {
 				buttonBar.dispose();
 			}
         }
     }


 	/**
      * Apply the dialog font to the composite and it's children
      * if it is set. Subclasses may override if they wish to
      * set the font themselves.
      * @param composite
      */
     protected void applyDialogFont(Composite composite) {
         Dialog.applyDialogFont(composite);
     }

     /**
      * Creates and returns an SWT label under the given composite.
      *
      * @param parent the parent composite
      * @return the new label
      */
     protected Label createDescriptionLabel(Composite parent) {
         Label result = null;
         String description = getDescription();
         if (description != null) {
             result = new Label(parent, SWT.WRAP);
             result.setFont(parent.getFont());
             result.setText(description);
         }
         return result;
     }

     /**
      * Computes the size needed by this page's UI control.
      * <p>
      * All pages should override this method and set the appropriate sizes
      * of their widgets, and then call <code>super.doComputeSize</code>.
      * </p>
      *
      * @return the size of the preference page encoded as
      *   <code>new Point(width,height)</code>
      */
     protected Point doComputeSize() {
         if (descriptionLabel != null && body != null) {
             Point bodySize = body.computeSize(SWT.DEFAULT, SWT.DEFAULT, true);
             GridData gd = (GridData) descriptionLabel.getLayoutData();
             gd.widthHint = bodySize.x;
         }
         return getControl().computeSize(SWT.DEFAULT, SWT.DEFAULT, true);
     }

     /**
      * Returns the preference store of this preference page.
      * <p>
      * This is a framework hook method for subclasses to return a
      * page-specific preference store. The default implementation
      * returns <code>null</code>.
      * </p>
      *
      * @return the preference store, or <code>null</code> if none
      */
     protected IPreferenceStore doGetPreferenceStore() {
         return null;
     }

     /**
      * Returns the container of this page.
      *
      * @return the preference page container, or <code>null</code> if this
      *   page has yet to be added to a container
      */
     public IPreferencePageContainer getContainer() {
         return container;
     }

     /**
      * Returns the preference store of this preference page.
      *
      * @return the preference store , or <code>null</code> if none
      */
     public IPreferenceStore getPreferenceStore() {
         if (preferenceStore == null) {
 			preferenceStore = doGetPreferenceStore();
 		}
         if (preferenceStore != null) {
 			return preferenceStore;
 		} else if (container != null) {
 			return container.getPreferenceStore();
 		}
         return null;
     }

     /**
      * The preference page implementation of an <code>IPreferencePage</code>
      * method returns whether this preference page is valid. Preference
      * pages are considered valid by default; call <code>setValid(false)</code>
      * to make a page invalid.
      * @see IPreferencePage#isValid()
      */
     public boolean isValid() {
         return isValid;
     }

     /**
      * Suppresses creation of the standard Default and Apply buttons
      * for this page.
      * <p>
      * Subclasses wishing a preference page without these buttons
      * should call this framework method before the page's control
      * has been created.
      * </p>
      */
     protected void noDefaultAndApplyButton() {
         createDefaultAndApplyButton = false;
     }

     /**
      * The <code>PreferencePage</code> implementation of this
      * <code>IPreferencePage</code> method returns <code>true</code>
      * if the page is valid.
      * @see IPreferencePage#okToLeave()
      */
     public boolean okToLeave() {
         return isValid();
     }

     /**
      * Performs special processing when this page's Apply button has been pressed.
      * <p>
      * This is a framework hook method for sublcasses to do special things when
      * the Apply button has been pressed.
      * The default implementation of this framework method simply calls
      * <code>performOk</code> to simulate the pressing of the page's OK button.
      * </p>
      *
      * @see #performOk
      */
     protected void performApply() {
         performOk();
     }

     /**
      * The preference page implementation of an <code>IPreferencePage</code>
      * method performs special processing when this page's Cancel button has
      * been pressed.
      * <p>
      * This is a framework hook method for subclasses to do special things when
      * the Cancel button has been pressed. The default implementation of this
      * framework method does nothing and returns <code>true</code>.
      * @see IPreferencePage#performCancel()
      */
     public boolean performCancel() {
         return true;
     }

     /**
      * Performs special processing when this page's Defaults button has been pressed.
      * <p>
      * This is a framework hook method for subclasses to do special things when
      * the Defaults button has been pressed.
      * Subclasses may override, but should call <code>super.performDefaults</code>.
      * </p>
      */
     protected void performDefaults() {
         updateApplyButton();
     }


     /* (non-Javadoc)
      * @see org.eclipse.jface.preference.IPreferencePage#performOk()
      */
     public boolean performOk() {
         return true;
     }


     /* (non-Javadoc)
      * @see org.eclipse.jface.preference.IPreferencePage#setContainer(org.eclipse.jface.preference.IPreferencePageContainer)
      */
     public void setContainer(IPreferencePageContainer container) {
         this.container = container;
     }

     /**
      * Sets the preference store for this preference page.
      * <p>
      * If preferenceStore is set to null, getPreferenceStore
      * will invoke doGetPreferenceStore the next time it is called.
      * </p>
      *
      * @param store the preference store, or <code>null</code>
      * @see #getPreferenceStore
      */
     public void setPreferenceStore(IPreferenceStore store) {
         preferenceStore = store;
     }


     /* (non-Javadoc)
      * @see org.eclipse.jface.preference.IPreferencePage#setSize(org.eclipse.swt.graphics.Point)
      */
     public void setSize(Point uiSize) {
         Control control = getControl();
         if (control != null) {
             control.setSize(uiSize);
             size = uiSize;
         }
     }

     /**
      * The <code>PreferencePage</code> implementation of this <code>IDialogPage</code>
      * method extends the <code>DialogPage</code> implementation to update
      * the preference page container title. Subclasses may extend.
      * @see IDialogPage#setTitle(String)
      */
     public void setTitle(String title) {
         super.setTitle(title);
         if (getContainer() != null) {
 			getContainer().updateTitle();
 		}
     }

     /**
      * Sets whether this page is valid.
      * The enable state of the container buttons and the
      * apply button is updated when a page's valid state
      * changes.
      * <p>
      *
      * @param b the new valid state
      */
     public void setValid(boolean b) {
         boolean oldValue = isValid;
         isValid = b;
         if (oldValue != isValid) {
             // update container state
             if (getContainer() != null) {
 				getContainer().updateButtons();
 			}
             // update page state
             updateApplyButton();
         }
     }


     /* (non-Javadoc)
      * @see java.lang.Object#toString()
      */
     public String toString() {
         return getTitle();
     }

     /**
      * Updates the enabled state of the Apply button to reflect whether
      * this page is valid.
      */
     protected void updateApplyButton() {
         if (applyButton != null) {
 			applyButton.setEnabled(isValid());
 		}
     }

     /**
      * Creates a composite with a highlighted Note entry and a message text.
      * This is designed to take up the full width of the page.
      *
      * @param font the font to use
      * @param composite the parent composite
      * @param title the title of the note
      * @param message the message for the note
      * @return the composite for the note
      */
     protected Composite createNoteComposite(Font font, Composite composite,
             String title, String message) {
         Composite messageComposite = new Composite(composite, SWT.NONE);
         GridLayout messageLayout = new GridLayout();
         messageLayout.numColumns = 2;
         messageLayout.marginWidth = 0;
         messageLayout.marginHeight = 0;
         messageComposite.setLayout(messageLayout);
         messageComposite.setLayoutData(new GridData(
                 GridData.HORIZONTAL_ALIGN_FILL));
         messageComposite.setFont(font);

         final Label noteLabel = new Label(messageComposite, SWT.BOLD);
         noteLabel.setText(title);
         noteLabel.setFont(JFaceResources.getFontRegistry().getBold(
 				JFaceResources.DEFAULT_FONT));
         noteLabel
                 .setLayoutData(new GridData(GridData.VERTICAL_ALIGN_BEGINNING));

         final IPropertyChangeListener fontListener = new IPropertyChangeListener() {
             public void propertyChange(PropertyChangeEvent event) {
                 if (JFaceResources.BANNER_FONT.equals(event.getProperty())) {
                     noteLabel.setFont(JFaceResources
                             .getFont(JFaceResources.BANNER_FONT));
                 }
             }
         };
         JFaceResources.getFontRegistry().addListener(fontListener);
         noteLabel.addDisposeListener(new DisposeListener() {
             public void widgetDisposed(DisposeEvent event) {
                 JFaceResources.getFontRegistry().removeListener(fontListener);
             }
         });

         Label messageLabel = new Label(messageComposite, SWT.WRAP);
         messageLabel.setText(message);
         messageLabel.setFont(font);
         return messageComposite;
     }

     /**
      * Returns the Apply button.
      *
      * @return the Apply button
      */
     protected Button getApplyButton() {
         return applyButton;
     }

     /**
      * Returns the Restore Defaults button.
      *
      * @return the Restore Defaults button
      */
     protected Button getDefaultsButton() {
         return defaultsButton;
     }

     /* (non-Javadoc)
      * @see org.eclipse.jface.dialogs.IDialogPage#performHelp()
      */
     public void performHelp() {
         getControl().notifyListeners(SWT.Help, new Event());
     }

 	/**
 	 * Apply the data to the receiver. By default do nothing.
 	 * @param data
 	 * @since 3.1
 	 */
 	public void applyData(Object data) {

 	}

 	/* (non-Javadoc)
 	 * @see org.eclipse.jface.dialogs.DialogPage#setErrorMessage(java.lang.String)
 	 */
 	public void setErrorMessage(String newMessage) {
 		super.setErrorMessage(newMessage);
 		if (getContainer() != null) {
 			getContainer().updateMessage();
 		}
 	}

 	/* (non-Javadoc)
 	 * @see org.eclipse.jface.dialogs.DialogPage#setMessage(java.lang.String, int)
 	 */
 	public void setMessage(String newMessage, int newType) {
 		super.setMessage(newMessage, newType);
 		if (getContainer() != null) {
 			getContainer().updateMessage();
 		}
 	}

 }
	/*******************************************************************************
	* Copyright (c) 2000, 2007 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
	* Sebastian Davids <sdavids@gmx.de> - Fix for bug 38729 - [Preferences]
	* NPE PreferencePage isValid.
	*******************************************************************************/
	package org.eclipse.jface.preference;

	import org.eclipse.jface.dialogs.Dialog;
	import org.eclipse.jface.dialogs.DialogPage;
	import org.eclipse.jface.dialogs.IDialogConstants;
	import org.eclipse.jface.dialogs.IDialogPage;
	import org.eclipse.jface.resource.ImageDescriptor;
	import org.eclipse.jface.resource.JFaceResources;
	import org.eclipse.jface.util.IPropertyChangeListener;
	import org.eclipse.jface.util.PropertyChangeEvent;
	import org.eclipse.swt.SWT;
	import org.eclipse.swt.events.DisposeEvent;
	import org.eclipse.swt.events.DisposeListener;
	import org.eclipse.swt.events.SelectionAdapter;
	import org.eclipse.swt.events.SelectionEvent;
	import org.eclipse.swt.graphics.Font;
	import org.eclipse.swt.graphics.Point;
	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;

	/**
	* Abstract base implementation for all preference page implementations.
	* <p>
	* Subclasses must implement the <code>createControl</code> framework
	* method to supply the page's main control.
	* </p>
	* <p>
	* Subclasses should extend the <code>doComputeSize</code> framework
	* method to compute the size of the page's control.
	* </p>
	* <p>
	* Subclasses may override the <code>performOk</code>, <code>performApply</code>,
	* <code>performDefaults</code>, <code>performCancel</code>, and <code>performHelp</code>
	* framework methods to react to the standard button events.
	* </p>
	* <p>
	* Subclasses may call the <code>noDefaultAndApplyButton</code> framework
	* method before the page's control has been created to suppress
	* the standard Apply and Defaults buttons.
	* </p>
	*/
	public abstract class PreferencePage extends DialogPage implements
	IPreferencePage {

	/**
	* Preference store, or <code>null</code>.
	*/
	private IPreferenceStore preferenceStore;

	/**
	* Valid state for this page; <code>true</code> by default.
	*
	* @see #isValid
	*/
	private boolean isValid = true;

	/**
	* Body of page.
	*/
	private Control body;

	/**
	* Whether this page has the standard Apply and Defaults buttons;
	* <code>true</code> by default.
	*
	* @see #noDefaultAndApplyButton
	*/
	private boolean createDefaultAndApplyButton = true;

	/**
	* Standard Defaults button, or <code>null</code> if none.
	* This button has id <code>DEFAULTS_ID</code>.
	*/
	private Button defaultsButton = null;

	/**
	* The container this preference page belongs to; <code>null</code>
	* if none.
	*/
	private IPreferencePageContainer container = null;

	/**
	* Standard Apply button, or <code>null</code> if none.
	* This button has id <code>APPLY_ID</code>.
	*/
	private Button applyButton = null;

	/**
	* Description label.
	*
	* @see #createDescriptionLabel(Composite)
	*/
	private Label descriptionLabel;

	/**
	* Caches size of page.
	*/
	private Point size = null;


	/**
	* Creates a new preference page with an empty title and no image.
	*/
	protected PreferencePage() {
	this(""); //$NON-NLS-1$
	}

	/**
	* Creates a new preference page with the given title and no image.
	*
	* @param title the title of this preference page
	*/
	protected PreferencePage(String title) {
	super(title);
	}

	/**
	* Creates a new abstract preference page with the given title and image.
	*
	* @param title the title of this preference page
	* @param image the image for this preference page,
	* or <code>null</code> if none
	*/
	protected PreferencePage(String title, ImageDescriptor image) {
	super(title, image);
	}

	/**
	* Computes the size for this page's UI control.
	* <p>
	* The default implementation of this <code>IPreferencePage</code>
	* method returns the size set by <code>setSize</code>; if no size
	* has been set, but the page has a UI control, the framework
	* method <code>doComputeSize</code> is called to compute the size.
	* </p>
	*
	* @return the size of the preference page encoded as
	* <code>new Point(width,height)</code>, or
	* <code>(0,0)</code> if the page doesn't currently have any UI component
	*/
	public Point computeSize() {
	if (size != null) {
	return size;
	}
	Control control = getControl();
	if (control != null) {
	size = doComputeSize();
	return size;
	}
	return new Point(0, 0);
	}

	/**
	* Contributes additional buttons to the given composite.
	* <p>
	* The default implementation of this framework hook method does
	* nothing. Subclasses should override this method to contribute buttons
	* to this page's button bar. For each button a subclass contributes,
	* it must also increase the parent's grid layout number of columns
	* by one; that is,
	* <pre>
	* ((GridLayout) parent.getLayout()).numColumns++);
	* </pre>
	* </p>
	*
	* @param parent the button bar
	*/
	protected void contributeButtons(Composite parent) {
	}

	/**
	* Creates and returns the SWT control for the customized body
	* of this preference page under the given parent composite.
	* <p>
	* This framework method must be implemented by concrete subclasses. Any
	* subclass returning a <code>Composite</code> object whose <code>Layout</code>
	* has default margins (for example, a <code>GridLayout</code>) are expected to
	* set the margins of this <code>Layout</code> to 0 pixels.
	* </p>
	*
	* @param parent the parent composite
	* @return the new control
	*/
	protected abstract Control createContents(Composite parent);

	/**
	* The <code>PreferencePage</code> implementation of this
	* <code>IDialogPage</code> method creates a description label
	* and button bar for the page. It calls <code>createContents</code>
	* to create the custom contents of the page.
	* <p>
	* If a subclass that overrides this method creates a <code>Composite</code>
	* that has a layout with default margins (for example, a <code>GridLayout</code>)
	* it is expected to set the margins of this <code>Layout</code> to 0 pixels.
	* @see IDialogPage#createControl(Composite)
	*/
	public void createControl(Composite parent){

	GridData gd;
	Composite content = new Composite(parent, SWT.NONE);
	setControl(content);
	GridLayout layout = new GridLayout();
	layout.marginWidth = 0;
	layout.marginHeight = 0;
	content.setLayout(layout);
	//Apply the font on creation for backward compatibility
	applyDialogFont(content);

	// initialize the dialog units
	initializeDialogUnits(content);

	descriptionLabel = createDescriptionLabel(content);
	if (descriptionLabel != null) {
	descriptionLabel.setLayoutData(new GridData(
	GridData.FILL_HORIZONTAL));
	}

	body = createContents(content);
	if (body != null) {
	// null is not a valid return value but support graceful failure
	body.setLayoutData(new GridData(GridData.FILL_BOTH));
	}

	Composite buttonBar = new Composite(content, SWT.NONE);
	layout = new GridLayout();
	layout.numColumns = 0;
	layout.marginHeight = 0;
	layout.marginWidth = 0;
	layout.makeColumnsEqualWidth = false;
	buttonBar.setLayout(layout);

	gd = new GridData(GridData.HORIZONTAL_ALIGN_END);

	buttonBar.setLayoutData(gd);

	contributeButtons(buttonBar);

	if (createDefaultAndApplyButton) {
	layout.numColumns = layout.numColumns + 2;
	String[] labels = JFaceResources.getStrings(new String[] {
	"defaults", "apply" }); //$NON-NLS-2$//$NON-NLS-1$
	int widthHint = convertHorizontalDLUsToPixels(IDialogConstants.BUTTON_WIDTH);
	defaultsButton = new Button(buttonBar, SWT.PUSH);
	defaultsButton.setText(labels[0]);
	Dialog.applyDialogFont(defaultsButton);
	GridData data = new GridData(GridData.HORIZONTAL_ALIGN_FILL);
	Point minButtonSize = defaultsButton.computeSize(SWT.DEFAULT,
	SWT.DEFAULT, true);
	data.widthHint = Math.max(widthHint, minButtonSize.x);
	defaultsButton.setLayoutData(data);
	defaultsButton.addSelectionListener(new SelectionAdapter() {
	public void widgetSelected(SelectionEvent e) {
	performDefaults();
	}
	});

	applyButton = new Button(buttonBar, SWT.PUSH);
	applyButton.setText(labels[1]);
	Dialog.applyDialogFont(applyButton);
	data = new GridData(GridData.HORIZONTAL_ALIGN_FILL);
	minButtonSize = applyButton.computeSize(SWT.DEFAULT, SWT.DEFAULT,
	true);
	data.widthHint = Math.max(widthHint, minButtonSize.x);
	applyButton.setLayoutData(data);
	applyButton.addSelectionListener(new SelectionAdapter() {
	public void widgetSelected(SelectionEvent e) {
	performApply();
	}
	});
	applyButton.setEnabled(isValid());
	applyDialogFont(buttonBar);
	} else {
	/* Check if there are any other buttons on the button bar.
	* If not, throw away the button bar composite. Otherwise
	* there is an unusually large button bar.
	*/
	if (buttonBar.getChildren().length < 1) {
	buttonBar.dispose();
	}
	}
	}



	/**
	* Apply the dialog font to the composite and it's children
	* if it is set. Subclasses may override if they wish to
	* set the font themselves.
	* @param composite
	*/
	protected void applyDialogFont(Composite composite) {
	Dialog.applyDialogFont(composite);
	}

	/**
	* Creates and returns an SWT label under the given composite.
	*
	* @param parent the parent composite
	* @return the new label
	*/
	protected Label createDescriptionLabel(Composite parent) {
	Label result = null;
	String description = getDescription();
	if (description != null) {
	result = new Label(parent, SWT.WRAP);
	result.setFont(parent.getFont());
	result.setText(description);
	}
	return result;
	}

	/**
	* Computes the size needed by this page's UI control.
	* <p>
	* All pages should override this method and set the appropriate sizes
	* of their widgets, and then call <code>super.doComputeSize</code>.
	* </p>
	*
	* @return the size of the preference page encoded as
	* <code>new Point(width,height)</code>
	*/
	protected Point doComputeSize() {
	if (descriptionLabel != null && body != null) {
	Point bodySize = body.computeSize(SWT.DEFAULT, SWT.DEFAULT, true);
	GridData gd = (GridData) descriptionLabel.getLayoutData();
	gd.widthHint = bodySize.x;
	}
	return getControl().computeSize(SWT.DEFAULT, SWT.DEFAULT, true);
	}

	/**
	* Returns the preference store of this preference page.
	* <p>
	* This is a framework hook method for subclasses to return a
	* page-specific preference store. The default implementation
	* returns <code>null</code>.
	* </p>
	*
	* @return the preference store, or <code>null</code> if none
	*/
	protected IPreferenceStore doGetPreferenceStore() {
	return null;
	}

	/**
	* Returns the container of this page.
	*
	* @return the preference page container, or <code>null</code> if this
	* page has yet to be added to a container
	*/
	public IPreferencePageContainer getContainer() {
	return container;
	}

	/**
	* Returns the preference store of this preference page.
	*
	* @return the preference store , or <code>null</code> if none
	*/
	public IPreferenceStore getPreferenceStore() {
	if (preferenceStore == null) {
	preferenceStore = doGetPreferenceStore();
	}
	if (preferenceStore != null) {
	return preferenceStore;
	} else if (container != null) {
	return container.getPreferenceStore();
	}
	return null;
	}

	/**
	* The preference page implementation of an <code>IPreferencePage</code>
	* method returns whether this preference page is valid. Preference
	* pages are considered valid by default; call <code>setValid(false)</code>
	* to make a page invalid.
	* @see IPreferencePage#isValid()
	*/
	public boolean isValid() {
	return isValid;
	}

	/**
	* Suppresses creation of the standard Default and Apply buttons
	* for this page.
	* <p>
	* Subclasses wishing a preference page without these buttons
	* should call this framework method before the page's control
	* has been created.
	* </p>
	*/
	protected void noDefaultAndApplyButton() {
	createDefaultAndApplyButton = false;
	}

	/**
	* The <code>PreferencePage</code> implementation of this
	* <code>IPreferencePage</code> method returns <code>true</code>
	* if the page is valid.
	* @see IPreferencePage#okToLeave()
	*/
	public boolean okToLeave() {
	return isValid();
	}

	/**
	* Performs special processing when this page's Apply button has been pressed.
	* <p>
	* This is a framework hook method for sublcasses to do special things when
	* the Apply button has been pressed.
	* The default implementation of this framework method simply calls
	* <code>performOk</code> to simulate the pressing of the page's OK button.
	* </p>
	*
	* @see #performOk
	*/
	protected void performApply() {
	performOk();
	}

	/**
	* The preference page implementation of an <code>IPreferencePage</code>
	* method performs special processing when this page's Cancel button has
	* been pressed.
	* <p>
	* This is a framework hook method for subclasses to do special things when
	* the Cancel button has been pressed. The default implementation of this
	* framework method does nothing and returns <code>true</code>.
	* @see IPreferencePage#performCancel()
	*/
	public boolean performCancel() {
	return true;
	}

	/**
	* Performs special processing when this page's Defaults button has been pressed.
	* <p>
	* This is a framework hook method for subclasses to do special things when
	* the Defaults button has been pressed.
	* Subclasses may override, but should call <code>super.performDefaults</code>.
	* </p>
	*/
	protected void performDefaults() {
	updateApplyButton();
	}


	/* (non-Javadoc)
	* @see org.eclipse.jface.preference.IPreferencePage#performOk()
	*/
	public boolean performOk() {
	return true;
	}


	/* (non-Javadoc)
	* @see org.eclipse.jface.preference.IPreferencePage#setContainer(org.eclipse.jface.preference.IPreferencePageContainer)
	*/
	public void setContainer(IPreferencePageContainer container) {
	this.container = container;
	}

	/**
	* Sets the preference store for this preference page.
	* <p>
	* If preferenceStore is set to null, getPreferenceStore
	* will invoke doGetPreferenceStore the next time it is called.
	* </p>
	*
	* @param store the preference store, or <code>null</code>
	* @see #getPreferenceStore
	*/
	public void setPreferenceStore(IPreferenceStore store) {
	preferenceStore = store;
	}


	/* (non-Javadoc)
	* @see org.eclipse.jface.preference.IPreferencePage#setSize(org.eclipse.swt.graphics.Point)
	*/
	public void setSize(Point uiSize) {
	Control control = getControl();
	if (control != null) {
	control.setSize(uiSize);
	size = uiSize;
	}
	}

	/**
	* The <code>PreferencePage</code> implementation of this <code>IDialogPage</code>
	* method extends the <code>DialogPage</code> implementation to update
	* the preference page container title. Subclasses may extend.
	* @see IDialogPage#setTitle(String)
	*/
	public void setTitle(String title) {
	super.setTitle(title);
	if (getContainer() != null) {
	getContainer().updateTitle();
	}
	}

	/**
	* Sets whether this page is valid.
	* The enable state of the container buttons and the
	* apply button is updated when a page's valid state
	* changes.
	* <p>
	*
	* @param b the new valid state
	*/
	public void setValid(boolean b) {
	boolean oldValue = isValid;
	isValid = b;
	if (oldValue != isValid) {
	// update container state
	if (getContainer() != null) {
	getContainer().updateButtons();
	}
	// update page state
	updateApplyButton();
	}
	}


	/* (non-Javadoc)
	* @see java.lang.Object#toString()
	*/
	public String toString() {
	return getTitle();
	}

	/**
	* Updates the enabled state of the Apply button to reflect whether
	* this page is valid.
	*/
	protected void updateApplyButton() {
	if (applyButton != null) {
	applyButton.setEnabled(isValid());
	}
	}

	/**
	* Creates a composite with a highlighted Note entry and a message text.
	* This is designed to take up the full width of the page.
	*
	* @param font the font to use
	* @param composite the parent composite
	* @param title the title of the note
	* @param message the message for the note
	* @return the composite for the note
	*/
	protected Composite createNoteComposite(Font font, Composite composite,
	String title, String message) {
	Composite messageComposite = new Composite(composite, SWT.NONE);
	GridLayout messageLayout = new GridLayout();
	messageLayout.numColumns = 2;
	messageLayout.marginWidth = 0;
	messageLayout.marginHeight = 0;
	messageComposite.setLayout(messageLayout);
	messageComposite.setLayoutData(new GridData(
	GridData.HORIZONTAL_ALIGN_FILL));
	messageComposite.setFont(font);

	final Label noteLabel = new Label(messageComposite, SWT.BOLD);
	noteLabel.setText(title);
	noteLabel.setFont(JFaceResources.getFontRegistry().getBold(
	JFaceResources.DEFAULT_FONT));
	noteLabel
	.setLayoutData(new GridData(GridData.VERTICAL_ALIGN_BEGINNING));

	final IPropertyChangeListener fontListener = new IPropertyChangeListener() {
	public void propertyChange(PropertyChangeEvent event) {
	if (JFaceResources.BANNER_FONT.equals(event.getProperty())) {
	noteLabel.setFont(JFaceResources
	.getFont(JFaceResources.BANNER_FONT));
	}
	}
	};
	JFaceResources.getFontRegistry().addListener(fontListener);
	noteLabel.addDisposeListener(new DisposeListener() {
	public void widgetDisposed(DisposeEvent event) {
	JFaceResources.getFontRegistry().removeListener(fontListener);
	}
	});

	Label messageLabel = new Label(messageComposite, SWT.WRAP);
	messageLabel.setText(message);
	messageLabel.setFont(font);
	return messageComposite;
	}

	/**
	* Returns the Apply button.
	*
	* @return the Apply button
	*/
	protected Button getApplyButton() {
	return applyButton;
	}

	/**
	* Returns the Restore Defaults button.
	*
	* @return the Restore Defaults button
	*/
	protected Button getDefaultsButton() {
	return defaultsButton;
	}

	/* (non-Javadoc)
	* @see org.eclipse.jface.dialogs.IDialogPage#performHelp()
	*/
	public void performHelp() {
	getControl().notifyListeners(SWT.Help, new Event());
	}

	/**
	* Apply the data to the receiver. By default do nothing.
	* @param data
	* @since 3.1
	*/
	public void applyData(Object data) {

	}

	/* (non-Javadoc)
	* @see org.eclipse.jface.dialogs.DialogPage#setErrorMessage(java.lang.String)
	*/
	public void setErrorMessage(String newMessage) {
	super.setErrorMessage(newMessage);
	if (getContainer() != null) {
	getContainer().updateMessage();
	}
	}

	/* (non-Javadoc)
	* @see org.eclipse.jface.dialogs.DialogPage#setMessage(java.lang.String, int)
	*/
	public void setMessage(String newMessage, int newType) {
	super.setMessage(newMessage, newType);
	if (getContainer() != null) {
	getContainer().updateMessage();
	}
	}

	}