Wednesday, December 17, 2008

Easy Syntax with WLST

WLST is a powerful scripting solution for managing and administering WebLogic Server and resources deployed on them. WLST is built on the Java implementation of the scripting language Python called as Jython. All the commands in WLST are implemented as Jython functions and they require a set of parentheses for passing any arguments. Even any commands that do not require any arguments are supposed to be suffixed with parentheses. For example the command "ls" is used to list all the child MBeans and/or attributes of the current MBean you are at.

ls() - lists all the child MBeans and attributes
ls('a') - lists all the attribute names and values only
ls('c') - lists all the child MBeans only

So even if you want to invoke "ls" with no arugments you must use "ls()". This might not be an issue when you are building scripts that you might want to run many times. But while connected to a server and working with WLST in interactive mode, it might get a little frustated to type the parentheses everytime you want to run some simple commands with no arguments. To ease this pain there is a hidden option in WLST which can be used to ease the syntax for WLST commands - easeSyntax().

You can supply the "easeSyntax()" command to ease the syntax but this is not recommended for script mode and especially when using loop constructs. You can also use the regular Jython syntax with parentheses even after you enabled the easy syntax. To turn off the easy syntax mode simply issue the command again "easeSyntax".

Bye Bye parentheses!