Package groovy.text

Class SimpleTemplateEngine

java.lang.Object
groovy.text.TemplateEngine
groovy.text.SimpleTemplateEngine
public class SimpleTemplateEngine
extends TemplateEngine
Processes template source files substituting variables and expressions into placeholders in a template source text to produce the desired output.

The template engine uses JSP style <% %> script and <%= %> expression syntax or GString style expressions. The variable 'out' is bound to the writer that the template is being written to.

Frequently, the template source will be in a file but here is a simple example providing the template as a string: 

 def binding = [
     firstname : "Grace",
     lastname  : "Hopper",
     accepted  : true,
     title     : 'Groovy for COBOL programmers'
 ]
 def engine = new groovy.text.SimpleTemplateEngine()
 def text = '''\
 Dear <%= firstname %> $lastname,

 We <% if (accepted) print 'are pleased' else print 'regret' %> \
 to inform you that your paper entitled
 '$title' was ${ accepted ? 'accepted' : 'rejected' }.

 The conference committee.
 '''
 def template = engine.createTemplate(text).make(binding)
 println template.toString()
This example uses a mix of the JSP style and GString style placeholders but you can typically use just one style if you wish. Running this example will produce this output: 
 Dear Grace Hopper,

 We are pleased to inform you that your paper entitled
 'Groovy for COBOL programmers' was accepted.

 The conference committee.
The template engine can also be used as the engine for TemplateServlet by placing the following in your web.xml file (plus a corresponding servlet-mapping element): 
 <servlet>
   <servlet-name>SimpleTemplate</servlet-name>
   <servlet-class>groovy.servlet.TemplateServlet</servlet-class>
   <init-param>
     <param-name>template.engine</param-name>
     <param-value>groovy.text.SimpleTemplateEngine</param-value>
   </init-param>
 </servlet>
In this case, your template source file should be HTML with the appropriate embedded placeholders.

  • Constructor Details

    • SimpleTemplateEngine

      public SimpleTemplateEngine()

    • SimpleTemplateEngine

      public SimpleTemplateEngine​(boolean verbose)

    • SimpleTemplateEngine

      public SimpleTemplateEngine​(java.lang.ClassLoader parentLoader)

    • SimpleTemplateEngine

      public SimpleTemplateEngine​(GroovyShell groovyShell)

  • Method Details

    • createTemplate

      public Template createTemplate​(java.io.Reader reader) throws CompilationFailedException, java.io.IOException
      Description copied from class: TemplateEngine
      Creates a template by reading content from the Reader.
      Specified by:
      createTemplate in class TemplateEngine
      Throws:
      CompilationFailedException
      java.io.IOException

    • setVerbose

      public void setVerbose​(boolean verbose)
      Parameters:
      verbose - true if you want the engine to display the template source file for debugging purposes

    • isVerbose

      public boolean isVerbose()

    • isEscapeBackslash

      public boolean isEscapeBackslash()

    • setEscapeBackslash

      public void setEscapeBackslash​(boolean escapeBackslash)