Skip to main content

Implementing cache in mobile (J2ME)

We can maintain cache/history of our visited entries in our mobile.

The method that can be used is "RecordStore"
how to do it:
1) Open a recordstore
2) add records to it.
Note: They'll be stored into mobile memories, you can't see these records as such in mobile

Now, when you want to view these records, open the recordstore again if it's closed. just open each record and perform the function.
You can append these records in a list so as to show them as a history maintained.

Problem welcome...

Comments

  1. Hi, My team has come up with a very simple mobile app for devices having java or symbian o/s. The challenge is we need to store data in the LDS of the handsets since the users of such app may not be always connected to internet, its a GPRS app. We wish to know how to implement cache to store small data in the handsets. And how do we identify what data to store. you may mail me karabi.bharadwaj@gmail.com, thanks.

    ReplyDelete
  2. What I pre-assume that your mobile is java enabled and you are using J2ME to develop that app.
    Now, coming to your question
    1) how to implement cache to store small data in the handsets?
    There is already provision in J2ME for caching mechanism. The API that implements it is *RecordStore*. Basically whatever records/data you want to cache is stored in mobile's internal memory. It's not accessible to you. Once you run the app again then only you can view the cached contents.
    So, you can write a function to be called each time you enter some value inside your app, which can open the already existing cache data (known as record store in J2ME) and write it to your new record/data.

    2) how do we identify what data to store?
    It depends on your app what you want to actually cache. The most frequently used data is generally cached. So, it totally depends upon your requirement. e.g., I used to send messages to only 4 of my friends out of my 1000 contacts. Then ofcourse, I would like to use their contacts as frequently as possible instead of typing or searching the contact details again and again.

    ReplyDelete

Post a Comment

Popular posts from this blog

VBA MAcro to generate "table of contents with hyperlinks" automatically in a ppt

VBA MAcro to generate "table of contents with hyperlinks" automatically in a ppt:



Function TableOfContent(count As Integer)
'count is the no. of slides in ppt
Dim var As Integer
Dim i As Integer, scount As Integer
Dim strSel As String, strTitle As String, strb As String, strtemp As String, str As String
Dim arr() As String
Dim index As Integer, indexcount As Integer, slidecount As Integer
Dim summary As Slide
Dim para As Integer
Dim slideOrder() As Integer


'To generate the Table of contents slide
ReDim slideOrder(count - 2)

'Collect all the IDs of the selected slides
For i = 1 To count - 2
slideOrder(i) = i + 2
Next

'Iterate over the slides in Index order
slidecount = UBound(slideOrder)
For scount = 1 To slidecount
If ActivePresentation.Slides(slideOrder(scount)).Shapes.HasTitle Then
'Build up the ToC Text
strTitle = ActivePresentation.Slides(slideOrder(scount)).Shapes("UseCase").TextFrame.TextRange.Text + ": "
str = ActivePresentation…

error in eclipse on import org.eclipse.jetty.server.Server;

When you find error in line import org.eclipse.jetty.server.Server; it means eclipse doesn't contain jetty.jar. Right click on project -> properties on left pane -> java build path right pane -> add external jar under libraries tab link it to all the jar files of jetty folder. can download jetty from : http://www.eclipse.org/jetty/downloads.php now rebuild the project.

How to do mass insert in redis

A basic and fairly easy way to do mass insert in redis:

Command to use: echo -e "$(cat redis_mass_insert.txt)" | redis-cli --pipe
Content of file "redis_mass_insert.txt": *3\r\n$5\r\nlpush\r\n$5\r\nu:m:1\r\n$5\r\nvalu1\r\n*3\r\n$5\r\nlpush\r\n$5\r\nu:m:1\r\n$7\r\nmyvalue\r\n

Result: All data transferred. Waiting for the last reply...
ERR unknown command ' *2'
ERR unknown command '$4'
ERR wrong number of arguments for 'echo' command
ERR unknown command '$20'
ERR unknown command ' A�j d�Q;yT��าก �h>'


NOTE: command line will show error but in actual the data is transferred and you can check it by entering in redis.

Here's the snapshot of the whole procedure:




To check how the command is responding: use hexdump -C
Command: echo -n $'$3\r\nset\r\n$3\r\nkey\r\n$5\r\nvalue\r\n ' | hexdump -C
whose output will be something like
00000000 24 33 0d 0a 73 65 74 0d 0a 24 33 0d 0a 6b 65 79 |$3..set..$3..key|
00000010 0d 0a…