XPath Formula Builder For XPath 1.0
TIBCO BusinessEvents uses XPath in the XPath Formula Builder, available in the Function Argument Mapper tool. You can use XPath, for example, when defining payloads for events TIBCO BusinessEvents also uses XPath as the language for defining conditions and transformations.
In XPath 1.0 , the XPath Formula Builder opens in a separate window; however, in XPath 2.0, the XPath Formula Builder is part of the Function Argument Mapping wizard. They both function in the same manner with only difference in user interface. See Function Argument Mapping Wizard for XPath 2.0 for more details on XPath Formula Builder for XPath 2.0.
XPath (XML Path Language) is an expression language developed by the World Wide Web Consortium (W3C) for addressing parts of XML documents. XPath also has basic manipulation functions for strings, numbers, and Boolean values.
To use XPath in TIBCO BusinessEvents, you need only be familiar with the basic XPath concepts, but you may wish to learn more about XPath when building complex expressions.
For a complete description of XPath, refer to the XPath specification (which can be obtained from www.w3.org).
TIBCO BusinessEvents uses XPath (XML Path Language) to identify elements whose content may be used, for, example in an event payload. You can also use XPath to perform basic manipulation and comparison of strings, numbers, and Boolean values.
- Addressing Schema Elements
All Scope Variables and Function arguments are represented as an XML schema. Regardless of where the data comes from or its format, TIBCO BusinessEvents represents the data as a schema tree. The data can be simple (strings, numbers, Boolean values, and so on), or it can be a complex element. Complex elements are structures that contain other schema elements, either simple elements or other complex elements. Both simple and complex elements can also repeat. That is, they can be lists that store more than one element of the given type. - Evaluation Context
XPath also has a method for referencing relative paths from a particular node. If you have an evaluation context, or a particular starting node in a schema tree, you can specify the relative path to other elements in the tree. - Namespaces
Some schema elements must be prefixed with their namespace. The namespace is automatically added to elements that require this when creating mappings or when dragging and dropping data in the XPath formula builder. - Search Predicates
An XPath expression can have a search predicate. The search predicate is used to locate a specific element of a repeating schema item. For example, a $GetOrderInformation/OrderDetails/OrderItem item is a repeating element. If you wish to select only the first item in the repeating element, you would specify the following: - Testing for Nil
Some elements can be explicitly set to nil. You can test an element to determine if it is set to nil or not. For example, the following XPath expression returns true if the $Order/Item/OnSale element is set to nil: - Comments
You can add comments to XPath expressions using the XPath 2.0 syntax for comments. The syntax is: - The XPath Formula Builder
You access the XPath Formula Builder using a button in the Function Argument Mapping Wizard. First select an item in the Function Argument panel (in the Input section). Then click the XPath Formula Builder button ().
- String Representations of Datatypes
When data must be represented in the input or output of an activity, the data is represented as a string. This section explains the string representations of various datatypes. TIBCO BusinessEvents follows the XPath 1.0 standard for representing all numeric datatypes. TIBCO BusinessEvents follows the XML Schema canonical format for all other datatypes. - Date and Time Functions
There are some functions in the XPath formula builder using which you can parse or format strings that represent dates and times. These functions are: