# com.bea.netuix.application.identifier
NavigableInstanceId Interface

public interface NavigableInstanceId
extends `InstanceId`

The `InstanceId` implemented by `Book`s and `Page`s, which are navigables. The `InstanceId` is stored in the database and uniquely identifies each instance of a `Book` or `Page`.

All Known Implementing Classes
  `PageInstanceId`, `BookInstanceId`

All Superinterfaces
  `InstanceId`

## Method Summary

`public int` | `getId`() Used when customizing `Book`s and `Page`s.

## Method Detail

### getId() Method

    public int getId()

Used when customizing `Book`s and `Page`s. Should not be null, but it's possible for this getter to return null if our internal API's were not called when creating the navigable, and the developer did not explicitly set it.

#### Returns

an integer representing the unique `InstanceId` for this navigable.