freemarker.template

Interface TemplateDirectiveModel

All Superinterfaces:

TemplateModel

All Known Implementing Classes:

IncludePage

public interface TemplateDirectiveModel
extends TemplateModel

"directive" template language data type: used as user-defined directives (much like macros) in templates. They can do arbitrary actions, write arbitrary text to the template output, and trigger rendering of their nested content for any number of times.

They are used in templates like <@myDirective foo=1 bar="wombat">...</@myDirective> (or as <@myDirective foo=1 bar="wombat" /> - the nested content is optional).

Since:

2.3.11

Field Summary

Fields inherited from interface freemarker.template.TemplateModel

NOTHING

Method Summary

Modifier and Type	Method and Description
void	execute(Environment env, java.util.Map params, TemplateModel[] loopVars, TemplateDirectiveBody body) Executes this user-defined directive; called by FreeMarker when the user-defined directive is called in the template.

Method Detail

execute

void execute(Environment env,
             java.util.Map params,
             TemplateModel[] loopVars,
             TemplateDirectiveBody body)
      throws TemplateException,
             java.io.IOException

Executes this user-defined directive; called by FreeMarker when the user-defined directive is called in the template.

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 TemplateException. (Note that setting Configuration.setWrapUncheckedExceptions(boolean) to true can mitigate the negative effects of implementations that throw RuntimeException-s.)

Parameters:

env - the current processing environment. Note that you can access the output Writer by Environment.getOut().

params - the parameters (if any) passed to the directive as a map of key/value pairs where the keys are String-s and the values 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.

loopVars - an array that corresponds to the "loop variables", in the order as they appear in the directive call. ("Loop variables" are out-parameters that are available to the nested body of the directive; see in the Manual.) You set the loop variables by writing this array. The length of the array gives the number of loop-variables that the caller has specified. Never null, but can be a zero-length array.

body - an object that can be used to render the nested content (body) of the directive call. If the directive call has no nested content (i.e., it's like <@myDirective /> or <@myDirective></@myDirective>), then this will be null.

Throws:

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

java.io.IOException - When writing the template output fails. Other IOException-s should be catched in this method and wrapped into TemplateException.