freemarker.template
Interface TemplateTransformModel

All Superinterfaces:
TemplateModel
All Known Implementing Classes:
CaptureOutput, HtmlEscape, JythonRuntime, NormalizeNewlines, StandardCompress, XmlEscape

public interface TemplateTransformModel
extends TemplateModel

Objects that implement this interface can be used in a <transform> block to perform arbitrary transformations on a part of the template processing output.

Note that, as of FreeMarker 2.1, TemplateTransform Model has changed. This is a more powerful implementation. There is a quick-and-dirty way to patch any legacy TemplateTransformModel so that it implements the new API. You simply add the following as your implementation of the getWriter() call:

 
    public Writer getWriter(final Writer out, 
                            Map args) 
    {
       final StringBuffer buf = new StringBuffer();
       return new Writer() {
           public void write(char cbuf[], int off, int len) {
               buf.append(cbuf, off, len);
           }

           public void flush() throws IOException {
               out.flush();
           }
 
           public void close() throws IOException {
               StringReader sr = new StringReader(buf.toString());
               StringWriter sw = new StringWriter();
               transform(sr, sw);
               out.write(sw.toString());
           }
       };
   }

 
 

Implementions of TemplateTransformModel should be thread-safe.

Version:
$Id: TemplateTransformModel.java,v 1.36 2003/04/11 20:57:32 revusky Exp $

Field Summary
 
Fields inherited from interface freemarker.template.TemplateModel
NOTHING
 
Method Summary
 java.io.Writer getWriter(java.io.Writer out, java.util.Map args)
          Returns a writer that will be used by the engine to feed the transformation input to the transform.
 

Method Detail

getWriter

java.io.Writer getWriter(java.io.Writer out,
                         java.util.Map args)
                         throws TemplateModelException,
                                java.io.IOException
Returns a writer that will be used by the engine to feed the transformation input to the transform. Each call to this method must return a new instance of the writer so that the transformation is thread-safe.

Parameters:
out - the character stream to which to write the transformed output
args - the arguments (if any) passed to the transformation as a map of key/value pairs where the keys are strings and the arguments are TemplateModel instances. This is never null.
Returns:
a writer to which the engine will feed the transformation input, or null if the transform does not support nested content (body). The returned writer can implement the TransformControl interface if it needs advanced control over the evaluation of the transformation body.
Throws:
TemplateModelException
java.io.IOException