Bug 172000 [Wizards] WizardNewFileCreationPage should support overwriting existing resources
In the WizardNewFileCreationPage, there should be a method to set allowExistingResources flag for ResourceAndContainerGroup member. It is useful when both "create" and "renew/overwrite" operations are meaningful for a wizard.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/misc/ResourceAndContainerGroup.java
*/
    private String resourceExtension;
    
    private static final int SIZING_TEXT_FIELD_WIDTH = 250;
    /**
     * Create an instance of the group to allow the user
     * to enter/select a container and specify a resource
     * name.
     *
     * @param parent composite widget to parent the group
     * @param client object interested in changes to the group's fields value
     * @param resourceFieldLabel label to use in front of the resource name field
     * @param resourceType one word, in lowercase, to describe the resource to the user (file, folder, project)
     */
    public ResourceAndContainerGroup(Composite parent, Listener client,
            String resourceFieldLabel, String resourceType) {
        this(parent, client, resourceFieldLabel, resourceType, true);
    }
	/**
     * Create an instance of the group to allow the user
     * to enter/select a container and specify a resource
     * name.
     *
     * @param parent composite widget to parent the group
     * @param client object interested in changes to the group's fields value
     * @param resourceFieldLabel label to use in front of the resource name field
     * @param resourceType one word, in lowercase, to describe the resource to the user (file, folder, project)
     * @param showClosedProjects whether or not to show closed projects
     */
    public ResourceAndContainerGroup(Composite parent, Listener client,