Support for "Loadable Dictionaries" - using DictionaryforMIDs on devices with small JAR-sizes
Development done - but certificate sill missing
The development of the "Loadable Dictionaries" is basically complete (well, a few nice-to-have features still should be implemented).
But one thing is missing: the certificate for DictionaryForMIDs !
Because the file system is accessed for the "Loadable Dictionaries", the DictionaryForMIDs application needs to be signed with a certificate. Otherwise, on most devices, the user will be prompted a confirmation dialogue each time when a file is accessed. For detailed technical information on this see the Recommended Security Policy for GSM/UMTS devices.
It needs to be checked whether somehow DictionaryForMIDs can obtain a certificate under conditions that are suitable for an Open Source project. A commercial certificate is expensive, for example a VeriSign code signing certificate costs about $500 per year, and unless there is a generous donor, the DictionaryForMIDs project cannot obtain such a commercial certificate.
General Background on "Loadable Dictionaries"
Many entry level cell phone models support only small JAR-file sizes, for example a few hundred kB. The dictionaries files that are incorporated into the DictionaryForMIDs_xxx.jar application JAR-file are often a few MB in size, so these dictionaries cannot be installed on those models.
But usually there are several MB of free space in the file system of the cell phone ! So let's put the dictionary there !
Basically all new models that appear on the market support JSR 75, including Nokias
popular Series 40 3rd edition. JSR 75 specifies a portable way of accessing the
file system of a cell phone/PDA. By using the JSR 75, the
DictionaryForMIDs_xxx.jar-file (this file contains the dictionary files) can be
put in the file system of the phone and the dictionary files can be read from
there. The DictionaryForMIDs_empty.jar (application JAR-file) does contain only
the program code and is much smaller.
Accessing the file system - already implemented !
The access to the file system is already implemented since version 3.1.0. The
class JSR75InputStream does the access via the JSR75 API. All other relevant
classes have also been extended, so that by now there is a working framework for
accessing the files in the file system. For how to use the current
implementation, the FAQ.
Implementing a 'file selection' dialogue - already implemented !
Joshua did implement a simple file selection dialogue to let the user select
a JAR file: The user is be able to pick within DictionaryForMIDs a
DictionaryForMIDs_xxx.jar-file that he downloaded from the
dictionary download page and did copy on the file system of his cell
Reading the JAR-files - already implemented !
Joshua did use the GNU Classpath ZIP-Library for reading JAR-files from
DictionaryForMIDs (JAR files use the file ZIP format). Based on this he
implemented the class ZipInputStreamAccess. All this really works fine ! But
some performance optimization is needed, read below.
- No restart of DictionaryForMIDs after selecting a dictionary
- Performance optimization for reading the dictionary data files when the user selects a JAR file
Currently, DictionaryForMIDs needs to be restarted after a dictionary is
selected in the file browser. This is annoying for the user and the
implementation needs to be improved so that this restart is not necessary.
1. No restart of DictionaryForMIDs after selecting a dictionary