Properties are variables that hold values associated with the request or response phase of an operation. A property value can correspond to a message element, a fragment of an element, the combined value of several elements from the same message, or an expression that uses a message element. You can use a message element from either the message header or body to define a property.
Properties are commonly used to facilitate searches, to surface message elements without having to log message content, to define conditions, and so on.
This section explains the different ways you can define and use properties.
Property definitions are shown in the Properties tab for any transaction that includes the service operation for which a property has been defined. Property definitions are also shown in the Properties tab for the service operation, endpoint operation, service, and endpoint. However, you can modify or delete a property only from the Properties tab for a transaction.
Using properties helps you do the following:
Surface aspects of a message that you would otherwise need to drill down to see. In fact, the use of properties can improve performance by making it possible for you to view values of message elements without having to log message content.
Define keys that allow you to manually correlate the operations that make up a transaction.
Segment transactions by consumer
Define a condition that depends on the value of a message property
For example, imagine you have a service element containing a customer ID. If you wanted to know which customers experience exceptions on a transaction that includes the operation, you could create a property to hold the value of the customer ID element. Then, when you inspect performance results, the ID of customers experiencing exceptions on that transaction would be prominently displayed.
A property can be based on any XPath expression defined on a request or response message, including message content or message headers (for example, SOAP headers, HTTP headers, or JMS message properties).
The simplest type of property holds the value of a single message element. For example, you might have the following message element:
OrcerServiceImpl.submit.request.order.orderId
You could create a property named Order_ID whose value is the value of this element.
You can also create a property that stores the result of a computation involving one or more message elements. For example, you might multiply an element that holds a price times a constant to compute tax:
OrderServiceImpl.submit.request.order.grandTotal *.0825
You could store the result in a property named Tax_Due.
In some cases, you might not be able to extract the data you need from messages directly. In these cases, you can create a property based on an XPath expression to extract data from your message and perform computations.
For example, if your message contains an indeterminate number of <item> elements, you could create a property to count the number of <item> elements in the message and store that value.
You might also use an XPath expression to extract data from an XML element that itself contains an encoded XML document.
Finally, you might have a service that is missing a WSDL. Using Business Transaction Management you can log a message from this service and then use the XML view to obtain the element you need to define the desired property.
The following subsections provide additional information about creating, modifying, duplicating, and deleting properties.