Hi,
By default all portal containers support these 3 modes (view/edit/help).
In view mode, you can show any content to the users. Using edit more , you can give users a chance to save their preferences or admins can configure the portlet. Using help mode, you can present the user some help content on how to access your portlet.
Let's take an example of simple bookmark portlet. In the VIEW mode, it shows the existing bookmark urls . And users can add/remove their bookmark by clicking on the EDIT mode. The help mode shows how to use the portlet.
What to put in VIEW or EDIT modes depends on your requirements. Please refer to some exisitng portlets to get clear idea.
Unlike
servlets, portlets supports two types of urls (Action url and Render url). Unlike servlets portlets has two mehtods (processAction and render).
For Action URL, the portlet container will call the processAction(..) which performs the backedn logic and then calls the render(..) which renders the content.
For Render URL, the portlet container will call the render(..) method directly and renders the content.
Generally, in the EDIT mode, we'll display a form with action url as the form submit action , so when the users edit some thing and save, the processAction will be executed. In processAction, we'll put our logic like persisting the data and setting required model data for our view. Finally the render method will be called which displays the content.
Please refer to the portlet specification (JSR168 ) for more information.
