Ant's current CVS version contains an <input> task that gathers user
input by reading from System.in - this is not too nice for people
embedding Ant in IDEs. 8-)

<input> also supports an undocumented testinput attribute that is used
by Ant's test cases to allow them to run without user interaction, but
could also be used to provide predefined answers to unattended builds.

This proposal tries to define a very basic input framework for Ant
that would allow Ant to be easily embedded into IDEs via
implementations of the org.apache.tools.ant.input.InputHandler
interface.  At the same time an implementation of the interface is
provided that allows the input to be specified via an external
property file.

There are three implementations of the InputHandler interface,
DefaultInputHandler which reads form System.in just like the <input>
task originally did, PropertyFileInputHandler for non-interactive
builds and SwingInputHandler which is nothing more than a proof of
concept.

Input requests get encapsulated in instances of the
org.apache.tools.ant.input.InputRequest class - or subclasses thereof
- which provide a method to also validate the input, moving this
responsibility from the <input> task to the InputRequest itself.

There are two types of InputRequests ATM, InputRequest encapsulates a
request for a simple unrestricted text input,
MultipleChoiceInputRequest is a request where valid inputs are
restricted to a given set of values.

If you run ant on the build file in this directory, a version of
ant.jar will be created in the build subdirectory that is identical to
the main trunk of Ant except for the input task itself and two minor
changes to Project and Main, that allow InputHandlers to be plugged in
programmatically or via a commandline switch -inputhandler.

With this version of Ant, run the input.xml build file in
proposals/testcases, Ant should behave the same way the input task for
the main branch does - except that it won't allow you to enter invalid
input in the multi target.

If you invoke Ant like this:

ant -f proposal/sandbox/input/src/testcases/input.xml -inputhandler org.apache.tools.ant.input.SwingInputHandler

You'll get the ugliest dialog you've ever seen, but it works ;-)

Use 

ANT_OPTS=-Dant.input.properties=proposal/sandbox/input/src/testcases/works.properties\
 ant -f proposal/sandbox/input/src/testcases/input.xml -inputhandler org.apache.tools.ant.input.PropertyFileInputHandler

to see the non-interactive build process in action.  fails.properties
provides a sample of possible input failures.

The original testcase for <input> has been ported to the new framework
as well, run it via

ant run-test

in this directory.