Discrete Wavelet Touransform

[trans]

Kindly give me the algorithm to perform discrete wavelet transform on an image.I have already separated the r,g,b planes.I am in in a fix as what to do after this.
I know that we have to do something like this
A+B
A-B
for rows
C+D
C-D
for columns
but how do I implement it using java.
Kindly help
Thank You