FunctionNode isNonnullFnNode = new FunctionNode("isNonnull");
isNonnullFnNode.addChild(operand0a);
ConditionalOpNode condOpNode = new ConditionalOpNode();
condOpNode.addChild(isNonnullFnNode);
condOpNode.addChild(operand0b);
condOpNode.addChild(operand1);
node.getParent().replaceChild(node, condOpNode);
}