Network Deployment (Distributed operating systems), v8.0 > Set up the application serving environment > Administer application servers > Create, edit, and delete WebSphere variables

WebSphere variables

WebSphere variables are name and value pairs that are used to provide settings for any of the string data type attributes that are used to configure the product. After a variable is defined, the symbolic name specified for that variable can be specified in the Value field of any other configuration field for the product that accepts a string value.

WebSphere variables can be used to configure:

When a variable is defined, it is given a scope. The scope is the range of locations within the product network where the variable is applicable.

The value of a configuration attribute can contain references to one or more variables. The syntax for such an attribute is the name of the variable, enclosed in either a pair of curly braces { } or a pair of parenthesis ( ). In either case, the variable is proceeded by the dollar sign.

A string configuration attribute value can consist of:

For Microsoft Windows operating systems, the specified file paths are prefixed wth /Program Files.

WebSphere variables and attributes . The following table illustrates all of the possible combinations.

Configuration attribute consists of: Configuration attribute value Variable name Second variable value Third variable value Fourth variable value Expanded configuration attribute value
String literal /IBM/WebSphere/AppServer N/A N/A N/A N/A /IBM/WebSphere/AppServer
Variable reference $(WAS_ INSTALL_ ROOT) WAS_ INSTALL_ ROOT /IBM/WebSphere/AppServer N/A N/A /IBM/WebSphere/AppServer
Variable reference with a string literal $(USER_ INSTALL_ ROOT)/temp USER_ INSTALL_ ROOT N/A N/A /IBM/WebSphere/AppServer/profiles/AppSrv01 /IBM/WebSphere/AppServer/profiles/AppSrv01/temp
Indirect variable reference with a string literal $(WAS_ INSTALL_ ROOT)/lib WAS_ INSTALL_ ROOT $(MY_INSTALL_ ROOT) MY_INSTALL_ ROOT N/A N/A
Nested variable references with string literal (Example 1) $(${INSTALL_ TYPE}_ INSTALL_ ROOT)/lib INSTALL_ TYPE USER USER_INSTALL_ ROOT /IBM/WebSphere/AppServer/profiles/AppSrv01 /IBM/WebSphere/AppServer/profiles/AppSrv01/lib
Nested variable references with string literal (Example 2) $(${INSTALL_ TYPE}_ INSTALL_ ROOT)/lib INSTALL_ TYPE WAS WAS_INSTALL_ ROOT /IBM/WebSphere/AppServer/AppServer /IBM/WebSphere/AppServer/AppServer/lib

During the configuration process, whenever a variable is encountered as the value for a configuration attribute, a variable expansion is performed on that variable. A variable expansion is the process of recursively replacing variable references with variable values until only a string literal remains as the value for the configuration attribute. If the expansion process encounters a variable that is not properly defined, the expansion of that variable stops and a VariableExpansionException exception is issued. The product configuration process continues. However, processing errors might occur because the value for this configuration attribute is not properly established. The variable expansion syntax provided in Versions 6.0.x, and 6.1.x, of the product, includes a variant that consists of a dollar sign, and a single letter variable name without any surrounding braces or parenthesis. This syntax is not supported in v8.0 or higher. All WebSphere variables references must be surrounded by matching parenthesis or braces, even if it is a single letter. That syntax required escaping of dollar signs to avoid ambiguity.

Literal dollar sign . For backward compatibility, the escaping of the literal dollar sign is still supported, and the literal dollar sign is interpreted as indicated in the following table.

Input value Value after expansion
$ $
$$ $
$$$ $$
$$$$ $$
$$$$$ $$$

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Create, edit, and delete WebSphere variables


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