8.4 The PDA Optional Package
The Java Specification Request 75 (JSR 75) was originally proposed to create a new CLDC-based J2ME profile (the PDA Profile) for low-end PDA devices (e.g., Palm PDAs). The PDA Profile was thought to be parallel to the MIDP. However, the progress of the JSR 75 has been very slow since August 2000. In the past three years, the MIDP has archived great success and is now a widely adopted industry standard. There is little need for another CLDC profile to compete with the MIDP now. In 2002, the JSR 75 expert group decided to reorganize and rename the JSR to the J2ME PDA Optional Package (PDA OP). This section is based on the proposed final draft of the PDA OP specification. The PDA OP runs on top the MIDP and provides two new packages to support PDA-specific features:The javax.microedition.io.file package supports access to local file systems through the J2ME Generic Connection Framework. We can open a connection to a file by passing the file://-style URL to the J2ME GCF abstract connection factory class (Connector). The package also includes support for dynamically mounted file systems (removable memory cards) through the FileSystemRegistry class and the FileSystemListener callback interface.The javax.microedition.pim package supports address books (ContactList and Contact), calendars (EventList and Event), and to-do lists (ToDoList and ToDo). The abstract factory class PIM provides methods to discover and retrieve those lists. If the device has a native PIM client, PDAP must provide access to all native database fields. The PDA OP imports and exports PIM entries in vCard and vCalendar formats.The two packages in the PDA OP are independent of each other. Device vendors can choose to implement either or both of them.
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