freemarker.template

Interface TemplateTransformModel

All Superinterfaces:

TemplateModel

All Known Implementing Classes:

CaptureOutput, HtmlEscape, JythonRuntime, NormalizeNewlines, StandardCompress, XmlEscape

public interface TemplateTransformModel
extends TemplateModel

"transform" template language data type: user-defined directives (much like macros) specialized on filtering output; you should rather use the newer TemplateDirectiveModel instead. This interface will certainly be deprecated in FreeMarker 2.4.

Field Summary

Fields inherited from interface freemarker.template.TemplateModel

NOTHING

Method Summary

Modifier and Type	Method and Description
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.

This method should not throw RuntimeException, nor IOException that wasn't caused by writing to the output. Such exceptions should be catched inside the method and wrapped inside a TemplateModelException. (Note that setting Configuration.setWrapUncheckedExceptions(boolean) to true can mitigate the negative effects of implementations that throw RuntimeException-s.)

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. Though it's recommended to work with TemplateModel-s directly.)

Returns:

The Writer to which the engine will write the content to transform, or null if the transform does not support nested content (body). The returned Writer may implements the TransformControl interface if it needs advanced control over the evaluation of the nested content. FreeMarker will call Writer.close() after the transform end-tag. Writer.close() must not close the Writer received as the out parameter (so if you are using a FilterWriter, you must override FilterWriter.close(), as by default that closes the wrapped Writer). Since 2.3.27 its also allowed to return the out writer as is, in which case it won't be closed.

Throws:

TemplateModelException - If any problem occurs that's not an IOException during writing the template output.

java.io.IOException - When writing to out (the parameter) fails. Other IOException-s should be catched in this method and wrapped into TemplateModelException.