ant target to kill previous target

I have an ant target to compile java classes and build war/ear in an a开发者_运维问答pplication. But this build takes longer time ie almost 5 min and need to wait till build completes. If i come to know ealier build is not correct, stop that build without manually killing and start new target after my new changes.

Now, I need another target which should stop the earlier build and start a new one. How can I do this? is this possible?

One possible solution : If you are in unix machine then you can check if a similar process is running. If it is not then continue.