Nullsafe Operator

The nullsafe operator is used in a chain of object property references. If one of the properties in the chain does not exist (in other words, it is considered NULL), the operator returns a value of NULL safely without issuing a warning.

In our example, we must have the following:

• An Extended Markup Language (XML) file named produce.xml.

• Lines 4–15: We also need to define a getQuantity() function that first checks to see if that property is not empty before proceeding to the next level.

• Lines 18–30: A code snippet that scans through the XML document and displays quantities.