package votorola.g.web.gwt; // Copyright 2012, Michael Allan.  Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Votorola Software"), to deal in the Votorola Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicence, and/or sell copies of the Votorola Software, and to permit persons to whom the Votorola Software is furnished to do so, subject to the following conditions: The preceding copyright notice and this permission notice shall be included in all copies or substantial portions of the Votorola Software. THE VOTOROLA SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE VOTOROLA SOFTWARE OR THE USE OR OTHER DEALINGS IN THE VOTOROLA SOFTWARE.

import com.google.gwt.user.client.rpc.AsyncCallback;
import votorola.g.hold.*;


/** A wrapper that disables an asynchronous callback when a spool is unwinding.
  */
public final class SpooledAsyncCallback<T> implements AsyncCallback<T>
{


    /** Creates an SpooledAsyncCallback.
      *
      *     @param spool the spool to use.
      *     @param callback the callback to guard.
      */
    public static <T> SpooledAsyncCallback<T> wrap( final Spool spool,
      final AsyncCallback<T> callback )
    {
        return new SpooledAsyncCallback<T>( spool, callback );
    }



    private SpooledAsyncCallback( Spool _spool, AsyncCallback<T> _callback )
    {
        spool = _spool;
        callback = _callback;
    }



   // - A s y n c - C a l l b a c k ------------------------------------------------------


    public void onFailure( final Throwable x )
    {
        if( !spool.isUnwinding() ) callback.onFailure( x );
    }



    public void onSuccess( final T result )
    {
        if( !spool.isUnwinding() ) callback.onSuccess( result );
    }



//// P r i v a t e ///////////////////////////////////////////////////////////////////////


    private final AsyncCallback<T> callback;



    private final Spool spool;


}