(Quick Reference)
                formatBoolean
Purpose
Outputs the given boolean as the specified text label.
Examples
<g:formatBoolean boolean="${myBoolean}" />
<g:formatBoolean boolean="${myBoolean}" true="True!" false="False!" />Description
Outputs the given boolean as the specified text label. If the 
true and 
false options are not given, the boolean is output using the default label.
Attributes:
boolean - the boolean to output
true (optional) - text label for boolean 
true value. 
boolean.true or 
default.boolean.true key is looked up from the Message Source / ResourceBundle (i18n/*.properties) if this attribute is not given.
false (optional) - text label for boolean 
false value. 
boolean.false or 
default.boolean.false key is looked up from the Message Source / ResourceBundle (i18n/*.properties) if this attribute is not given.
Source