Everything comes with a public API nowadays, and now so does GateIn Portal. This post introduces the Java API, there's also a REST API which there will be a separate post about.
For this release the main focus was on navigation, specifically manging portal navigations and creating custom navigation portlets.
Managing Portal Navigations
Portal navigations are menus that contain hyperlinks to other parts of a portal. In the past these could only be created through the web interface, but can now also be created through the Java or REST API's. Most operations that are required to manage portal navigations are supported. For example adding nodes to a portal navigation, moving nodes around, controlling permissions and managing internationalized labels for nodes.
For the full details on what can be done look at the Developer Guide: https://docs.jboss.org/author/display/GTNPORTAL36/Portal+API.
Custom Navigation Portlets
If the standard navigation portlets doesn't do the job for you, now it's very easy to create your own custom navigation portlet to build a menu exactly the way you want it. You can easily control what nodes are displayed in the menu with the filtering mechanism and how many levels of nodes to display with the node visitors mechanism.
There's a number of resources available to get you started: