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    <p class="comment">If something looks like this, this is either a
    request for input or a &quot;REVISIT&quot; marker or similar.</p>

    <h1>Ant2 Goals</h1>

    <p>Even though Ant2 is expected to be incompatible with the
    current Ant1 series, it still has the same goals. Ant is a Java
    based build tool and this remains the main focus of it. The
    original goals of simplicity, understandability and extensibility
    still stand and Ant2 will try to achieve them even better than
    Ant1 does.</p>

    <h2>Simplicity and Understandability</h2>

    <p>These two goals are closely related. Ant build files shall be
    easy to read and understand - at the same time it should be easy
    to write a custom Ant task and to use the utility classes that
    Ant2 provides.</p>

    <p>Ant2 shall be more consistent than Ant1 is - this means:</p>

    <ul>

      <li>core tasks will use the same attribute names for common
      functionality</li>

      <li>similar tasks will be unified to use similar forms.</li>

      <li>different implementations for the same functionality will be
      hidden behind facade tasks.</li>

      <li>properties and data types will be unified so that they share
      the same namespace and inheritance rules. <i
      class="comment">Need to talk about how ${} expansion works for
      filesets and so on.</i></li>

    </ul>

    <p>Furthermore some things will have to become more explicit:</p>

    <ul>

      <li>remove all magic properties</li>

      <li>make build file writers explicitly state which
      filters/filtersets a copy task will use</li>

      <li>add scoping rules for properties so that not all of them
      will be inherited by sub-builds, only those that have been
      specified explicitly. <i class="comment">Fill in details once
      they&apos;ve been sorted out.</i></li>

    </ul>

    <p>The front-ends for Ant2 shall be smart enough to automatically
    detect the required libraries (like <code>tools.jar</code>), the
    use of native scripts shall be kept to a minimum.</p>

    <p>Build file writers can attach a message to targets that will be
    presented to the user if that target is going to be skipped (based
    on the if/unless attribute of the target).</p>

    <h2>Extensibility</h2>

    <p>Ant2 like Ant1 uses build files written in XML as its main
    input, but it will not be restricted to it. The core of Ant2 will
    work on an object model of Project/Target/Task that is independent
    of any external representation.</p> 

    <p>As an extension of the current <code>&lt;taskdef&gt;</code>
    concept, tasks can be bundled into task libraries (together with
    data types and other utility classes). These task libraries are
    special JAR archives that somehow describe the contained tasks to
    Ant. Ant will automatically know all tasks contained in task
    libraries that have been placed into a special directory - in
    addition task libraries can be referenced and used in a build file
    explicitly. <i class="comment">Fill in details once they&apos;ve been
    sorted out.</i></p>

    <p>It has become apparent, that several &quot;aspects&quot; of
    tasks are so common that task writers find themselves duplicating
    code all over again - things like classpath handling or &quot;do
    we stop the build if this task fails?&quot; functionality for
    example. Ant2 will provide a way to let the user attach an
    &quot;aspect handler&quot; to a project - all attributes that live
    in a certain namespace are going to be passed to this handler. <i
    class="comment">Need to talk about TaskContext here.</i></p>

    <p>Ant2 will farm out common functionality from tasks into utility
    classes so that task writers can benefit from a tested and stable
    framework - they shouldn&apos;t need to deal with existing tasks
    directly (like some tasks &quot;abuse&quot; the
    <code>&lt;touch&gt;</code> task in Ant1).</p>

    <h1>New/Modified Features</h1>

    <p>Ant2 will run the build process fully dynamically, which means
    that task won&apos;t be instantiated before they are actually being run
    and <code>${}</code> expansion will see the very latest value of a
    property. It will be possible to reassign values of properties via
    a built-in task.</p>

    <h2>Compatibility with Ant1</h2>

    <p>Ant2 is going to break Ant1 in several ways:</p>

    <ul>

      <li>Tasks written for Ant1 won&apos;t work in Ant2 as the API of
      Ant&apos;s core and the names of utility classes are going to
      change. There will probably be adaptors and utility classes to
      ease the transition for task writers.</li>

      <li>Build files written for Ant1 will probably not be valid in
      Ant2 or at least not yield the same results. It is expected that
      Ant2 will come with a tool to translate Ant1 build files into
      equivalent Ant2 versions</li>

      <li>magic properties like <code>build.compiler</code> may
      disappear and be replaced by a different customization
      concept.</li>

      <li>Ant2 is going to require a JDK version 1.2 or above and a
      JAXP compliant parser version 1.1 or above.</li>

    </ul>

    <h2>Support Integration of Ant Into Other Tools</h2>

    <p>Ant2 will have a clear separation between the front-end that is
    responsible for user interactions, the object model that
    represents the project to build and the part of Ant that runs the
    build process itself <i class="comment">Name that TaskEngine,
    ProjectEngine, ExecutionEngine or what?</i>. This separation is
    expected to ease the integration of Ant (or parts of it) into
    other products.</p>

    <p>Ant2 itself will include a command line front-end and Antidote
    will become the GUI front-end to it. Other front-ends like a
    servlet front-end are expected <i class="comment">outside of
    Ant&apos;s core</i> as well.</p>

    <p>In addition to this separation, the following features should
    help people who want to integrate Ant into their products:</p>

    <ul>

      <li>It will be possible to cancel a running build process.</li>

    </ul>

    <h2>More Control for Users and Build File Writers</h2>

    <p>Ant2 will use a <code>BuildListener</code> concept similar to
    the one of Ant1 but may provide a richer set of events. It will be
    possible to attach and detach listeners to a build process from
    within the build file and to modify the behavior of attached
    listeners.</p>


    <h2>Documentation System</h2>

    <p>All tasks will be documented in XML files using a common DTD <i
    class="comment">Still need to define it</i> - task libraries are
    expected to include the documentation using this DTD inside the
    library itself.</p>

    <h2>Better Subbuild Handling</h2>

    <p class="comment">Is there something beyond &quot;should become
    better&quot; right now?</p>

    <h1>Rejected Features</h1>

    <p>This is list is not complete, it just highlights some of the
    rejected features and tries to explain why they&apos;ve been
    rejected.</p>

    <p>For a complete listing of all requested features, see <a
    href="requested-features.html">requested-features.html</a>. The
    discussion on all topics can be followed in the <a
    href="http://marc.theaimsgroup.com/?l=ant-dev&r=1&w=2">archives
    for ant-dev</a> in threads starting from 2001-03-21 - the subject
    lines contained either <code>[VOTE]</code> or
    <code>[DISC]</code>.</p>

    <h1>Ideas for New Tasks and Tools</h1>

    <p>Please refer to <a
    href="requested-features.html">requested-features.html</a> in the
    section &quot;I. Things that don&apos;t affect the core but are
    requests for new tasks or enhancements to existing tasks.&quot;
    for this.</p>

    <hr>
      <p align="center">$Id$</p>
      <p align="center">Copyright &copy; 2001 Apache Software
        Foundation. All rights Reserved.</p>
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