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 as user-defined directives (much like macros); you should rather use the newer TemplateDirectiveModel instead. Altough implementing output filters is more handy with this interface, this interface will be certainly deprecated as superfluous, starting from FreeMarker 2.4. But as far as the template engine is concerned, you can use both equivalently as a user-defined directive.

Note that, as of FreeMarker 2.1, TemplateTransformModel 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());
           }
       };
   }

 
 

Version:

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

Author:

Attila Szegedi

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. If you need to convert the template models to POJOs, you can use the utility methods in the DeepUnwrap class.

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