protected Object execute(Object[] obj, State state) {
        for (Object aObj : obj) {
            if (aObj != null) {
                return aObj;
            }
        }
        return null;
    }
Executor class for coalesce function. Returns the value of the first input parameter that is not null.
modules/siddhi-core/src/main/java/io/siddhi/core/executor/function/CoalesceFunctionExecutor.java