preferencepage.java

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     * 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.
     */
    public boolean isValid() {
        return isValid;
    }

    /**
     * Suppresses creation of the standard Default and Apply buttons
     * for this page.
     * <p>
     * Subclasses wishing a preference page wihthout 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.
     */
    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 sublcasses 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>.
     */
    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();
    }

    /** 
     * Method declared on IPreferencePage.
     * Subclasses should override
     */
    public boolean performOk() {
        return true;
    }

    /** (non-Javadoc)
     * Method declared on IPreferencePage.
     */
    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)
     * Method declared on IPreferencePage.
     */
    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.
     */
    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();
        }
    }

    /**
     * Returns a string suitable for debugging purpose only.
     */
    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.getBannerFont());
        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();
		}
	}	

}