Bug 168888 [Wizards] PageTransition classes may need rename/reorg
bundles/org.eclipse.jface/src/org/eclipse/jface/wizard/Wizard.java
}
    /*
     * (non-Javadoc) Method declared on IWizard. The default behavior is to
     * return the page that was added to this wizard before the given page.
     */
    public IWizardPage getPreviousPage(IWizardPage page) {
        int index = pages.indexOf(page);
        if (index == 0 || index == -1) {
			
            return null;
		} 
		return (IWizardPage) pages.get(index - 1);
    }
    /**
     * Returns the wizard's shell if the wizard is visible. Otherwise
     * <code>null</code> is returned.
     * 
     * @return Shell
     */
    public Shell getShell() {
        if (container == null) {
			return null;
		}
        return container.getShell();
    }
    /*
     * (non-Javadoc) Method declared on IWizard. By default this is the first
     * page inserted into the wizard.
     */
    public IWizardPage getStartingPage() {