Question

I have some 1000 key-pair values that I will use in my j2me application, reading it from a resource file. However I will be using only a few of those values at any time, say 10, based on the record number being generated inside the application logic. Loading all the values into memory and then looking up is fairly not an efficient option as I will not be using all the records. Is there a better scheme to store the values in the file, some indexing or something so that I can retrieve those key-pair values by skipping the amount of bytes in the file to reach and read the appropriate record? As this is a resource file in the jar there wont be any modifications to it.

Answer 1

If you know the record length when they are created, you could write the records out in binary format to a file. But at the start of each record, you could first write a number indicating its size in bytes and use a RandomAccessFile to access the records by moving the file pointer.
But in terms of speed, loading into memory will be faster than reading from a file, but if memory is at a premium, then a file wouldn’t be a bad way to go.

Jeff