The Content Handler API is an optional package for the JavaTM ME platform. This API and model let an application invoke registered Java ME and non-Java applications for content by URL, by content type, or by content handler ID. The application can use actions provided by the handler on the invoked content.
Content Handler API works as specified in the JSR-211 API specification, with the following considerations:
JSR-211 specification mandates HTTP support. Additionally HTTPS and file URL support is provided.
There is no limit set on the number of levels of MIDlet chaining, this is only limited by platform memory availability.
There is no gallery integration for invoking MIDlet content handlers via the content file in the gallery.
MIDlet to native invocation is not supported for files already on the phone.
Native applications do not have assigned application IDs that would enable MIDlets to invoke native content handlers directly by an application ID. They can however invoke native content handlers by content type for HTTP schemes.
Native content handlers can not be overridden by MIDlet content handlers. For example, when content is viewed in gallery, then the native content handler will always be triggered. MIDlets can still use a specific MIDlet content handler rather than a native content handler if it is referenced by application ID or specifies a particular action that MIDlet content handler supports.
It is not possible to exchange data between MIDlet and native content handlers.
It is not possible for native content handlers to pass the
result of an operation back to the invoking MIDlet. The state INITIATED is
used.
If a MMC card is removed then content handlers are automatically unregistered unless there is a short cut file to the MIDlet on the MMC card.
Not all of the native content handlers are accessible via a MIDlet invocation.
Native handlers are only found when the content type is explicitly searched for.
MIDlet content handlers are only registered on the WAP download channel. This means that MIDlet content handlers can be triggered when content is downloaded via the web browser but not when content is pushed to the phone by bluetooth.
There is no UI to ‘choose’ between content handlers registered for exactly the same content type and action(s). The MIDlet that registered for the content type last takes precedence.