Starting from v2.9.0, LiteFlow supports loop component, mainly used for WHILE...DO... expressions.

For the usage of the WHILE...DO... expression, you can refer to Loop mode.

you can define it as follows:

<chain name="chain1">
    WHILE(w).DO(THEN(a, b));
</chain>

The definition of the w node needs to inherit NodeWhileComponent and implement the processWhile method:

@LiteflowComponent("w")
public class WCmp extends NodeWhileComponent {
    @Override
    public boolean processWhile() throws Exception {
        //here to return the result of while
    }
}

See the chapter Common Components for the methods that can be overridden and the methods that can be called by the this keyword.