MAC Performance Monitoring

Hi all,

I want to develop an application for MAC OS X performance monitoring. I want to retrieve data such as

CPU usage
No. of active processes
No. of Threads
load
Used and free memory
Used and free disk space
Disk I/O
pages in/out per second
Network I/O
etc..

I want information regarding procedure to retrieve this data . I have been using Windows there we use the APIs and in Linux I use the proc directory and parse info using java.
Please help me out. I am very new to MAC.

Desperately waiting for some hints.

Savera