AntStructure Task

## AntStructure

### Description

Generates an DTD for Apache Ant buildfiles which contains information about all tasks currently known to Ant.

Actually the DTD will not be a real DTD for buildfiles since Ant's usage of XML cannot be captured with a DTD. Several elements in Ant can have different attribute lists depending on the element that contains them. "fail" for example can be the task or the nested child element of the sound task. Don't consider the generated DTD something to rely upon.

Also note that the DTD generated by this task is incomplete, you can always add XML entities using `<taskdef>` or `<typedef>`. See here for a way to get around this problem.

This task doesn't know about required attributes, all will be listed as `#IMPLIED`.

Since Ant 1.7 custom structure printers can be used instead of the one that emits a DTD. In order to plug in your own structure, you have to implement the interface `org.apache.tools.ant.taskdefs.AntStructure.StructurePrinter` and `<typedef> your class and use the new type as a nested element of this task - see the example below.`

### Parameters

Attribute | Description | Required
output | file to write the DTD to. | Yes

### Examples

>     <antstructure output="project.dtd" />

Emitting your own structure instead of a DTD

First you need to implement the interface

    package org.example;
    import org.apache.tools.ant.taskdefs.AntStructure;
    public class MyPrinter implements AntStructure.StructurePrinter {
        ...
    }

and then use it via typedef

      <typedef name="myprinter" classname="org.example.MyPrinter" />
      <antstructure output="project.my">
        <myprinter />
      </antstructure>

Your own StructurePrinter can accept attributes and nested elements just like any other Ant type or task.