Velocity Template Tutorial_4

FORMAL REFERENCE NOTATION :

• To understand formal-reference notation we need to understand the problem first.

PROBLEM:

In JAVA-CODE: VelocityContext context = new VelocityContext(); context.put("name","vignesh"); IN TEMPLATE-FILE:   I am $nameWaran When the above code is processed by velocity engine it thinks we are refrering to “$nameWaran” not “$name waran” so inorder to overcome this problem use formal-reference notation as I am ${name}Waran

ESCAPE CHARACTER :(\)

USAGE 1: #set($name=”vignesh”) $name \$name ## using ESCAPE CHARACTER \\$name	OUTPUT vignesh $name \vignesh
USAGE 2: #set($name =”vignesh”) #set($escapeName =”$name”) #set($dontEscapeName =$name) $name $escapeName $dontEscapeName	OUTPUT vignesh $name vignesh

VELOCITY-CONTEXT CHAINING:

• Used to mearge to velocity context into one.

• Can chain any number of Context.

• EXAMPLE :  

LINE	PROGRAMMING	EXPLANATION
1 2 3 4 5 6 7 8	VelocityContext context1 = new VelocityContext(); context1.put("name","Velocity"); context1.put("project", "Jakarta"); context1.put("duplicate", "I am in context1"); VelocityContext context2 = new VelocityContext( context1 );   context2.put("lang", "Java" ); context2.put("duplicate", "I am in context2"); template.merge( context2, writer )	Line 1:Create-context_1 object. Line 2&3&4 : Adding values to context. LINE 5 :Creating context_2 and add context_1 to context_2[Chaining the context] LINE 6&7 : Adding values to context. Line 8:Merging

POINTS TO REMEMBER :

• If want to use replacement for JSP then we can use cache.

• We can create event handlers like if any exception occurs like NULLPOINTEREXCEPTION we can use Event handlers to handlle that.

• Using Properties files to giving extra info to velocity engine like using UTF-8 encoding

• See Documentation for Full Details.
  
  

Note : If you find any thing which you can not understand or wrong please leave comments.I assure i will get back to you.

 
NOTE : TO download the velocity tutorial in word format click here