XForms Processor

The XForms processor is created as a core component which implements all the processing rules and logic as specified in the XForms specification. The processor can be looked at as an abstract version of an XForms processor since it does not have any code for creating a user interface nor does it has code for communication. To use the processor it is necessary to create code for network communication and for render controls onto the screen. The processor does provide code for doing this as easy as possible and therefore the amount of work is limited.

The processor was created with the purpose of:

• being correct and stable implemented according to the XForms specification.
• being easy to extend with actions and XPath functions.
• being fast and portable for being suitable to small devices as e.g. mobile phones.

The processor provides a public API which must be used for interfacing. The central point of this is the DOM which is the glue between the processors and renderings (there can be more than one rendering at a time). This works by creating a behavior (a java object implementing a special interface) and a behavior factory which is attached to the DOM. When the DOM creates elements it will ask the factory for a behavior which is then installed in the DOM. The XForms processor is implemented in the same way and will also install behaviors in the DOM. When the processor communicates with the user interface it calls methods on all behaviors which is installed on the same elements as it-self which implements a specific notification interface. When a rendering behavior wants to communication with the XForms processor it asks the DOM for the XForms behavior on an element (e.g. an <xforms:input> element) and calls methods on it for setting and getting properties and so on.