JeeWiz Architect's Guide - #while and #break/#continue


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JeeWiz Architect's Guide

Contents > 8. Templates and Velocity Features

8.7 #while and #break/#continue

These directives are additional to standard Velocity. #while gives an alternative to #foreach. #break/#continue and their '2' variants give more control within #foreach and #while.

These directives are relatively new and so there are currently not many examples of their use in the codebase (as of verson 5.0).

8.7.1	The #while directive
8.7.2	Loop Control Directives: #break and #continue

8.7.1 The #while directive

The #while directive allows you to construct a loop without using specific values like the #foreach loop does.

The syntax is as follows:

Option 1 - using a conditional expression:

#while( expression )
   statements+
#end

Option 2 - no expression, - and the '()' is normally omitted too:
#while statements+ #end
This is equivalent to a version 1 where the expression is "true". To terminate this loop, there must be a #break statement executed.

There must be at least one statement as the body of the #while - just as #foreach.

8.7.2 Loop Control Directives: #break and #continue

Just like Java, the #break directive breaks out of an enclosing loop; the #continue directive starts another go-round of an enclosing loop. #foreach and #while are the loop directives.

There are also 2-loop variants: the #break2 and #continue2.

If the loop control directives are not in the necessary loop directive, this causes a runtime exception.