How can I stop jButton action?

private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
//codes for initializing & calculating value of a  
if(a==1){
//if this condition is true jButton action will Continue 
//jButton action code ......}
else{
//if this condition is false jButton action will stop.

if a value is not equal to 1 , I just want to stop the action of jButton1. I don't want to stop the whole code & rerun action of jButton1. while a is getting 1. How can I do this?