Updating MIDlet Suites





Updating MIDlet Suites

When a user requests the installation of a MIDlet that is already on the device, the device should treat this as a request to update the MIDlet suite. (If the version of the requested MIDlet suite is the same as the version on the device, this can also be called reinstalling. From the device perspective, though, it is an update.)

MIDP Implementors

Strongly Recommend: graphics/bulb1_icon.gif Before you perform the update, the user must confirm the operation. In the screen that requests confirmation, tell the user whether the requested MIDlet suite is older, newer, or the same as the version on the device. Figure shows a Confirmation screen from the MIDP 2.0 Reference Implementation.

15. Confirmation Screen for Updating a MIDlet Suite

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MIDP implementations should not charge users for reinstalling a MIDlet suite after they have paid for it. They might be reinstalling it because they deleted it by mistake, or because it was corrupted on their device. In either case, they have already paid for the use of that version of the MIDlet suite. (See "Personal Storage for MIDlet Suites" on page 185 for one way that the user could reinstall a MIDlet suite without being charged.)

1 Security

MIDP Implementors

Strongly Recommend: graphics/bulb1_icon.gif If the MIDlet suite being updated had a digital signature to show that it was from a trusted entity and had not been tampered with, you must not permit the user to update it with an unsigned MIDlet suite.

If the MIDlet suite being updated included protected functionality, the new MIDlet should use the same permission levels.

2 Application Data

MIDP Implementors

Strongly Recommend: graphics/bulb1_icon.gif If the MIDlets from the MIDlet suite being updated have saved data on the device, make it available to the updated MIDlet suite if it is identical to the existing MIDlet suite, or if its JAR or JAD file is from the same location as the one for the existing MIDlet suite.

If the updated MIDlet suite is not identical or from the same location as the existing MIDlet suite, ask the user whether to keep the data. Figure shows a screen that queries the user.

16. Confirmation Screen for Saving a MIDlet Suite's Data

graphics/13fig16.gif


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