Appendix C. Inter-portlet communication
This appendix exists because I really wanted to cover inter-portlet communication (IPC) in the book. I think it’s a core portlet skill, because much of the power of making portlet applications is the ability to make your applications modular. You can write one portlet that shows customers in a list, have a user click one of those customers, and then have their orders show up in another portlet on the page. The portal framework gives you the power to drag these portlets around and arrange them on the page any way you like. It’s very powerful.
Unfortunately, the chapter I came up with didn’t fit nicely into the book. The code wasn’t Liferay-specific (because this is a core portlet skill), the example had nothing to do with Inkwell, and there was no good place to put the chapter. But I still wanted to put it in the book, somehow—so here it is, in an appendix.
You may have seen how easy it is to write a portlet. You may have been introduced to the basics of the Portlet API and used features from Portlet 1.0 to achieve this. We’re now going to look at some of the things that Portlet 2.0 brings to the table. Of course, the best way to do this is by example. But first, I want to give you a little history of the portlet specification.