package votorola.g.hold; // Copyright 2005-2006, 2010, 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 java.util.*;
import votorola.g.lang.Catcher;


/** An implementation of a spool based on a linked list.
  */
public final class Spool1 implements Spool
{


   // - S p o o l ------------------------------------------------------------------------


    public boolean add( Hold hold )
    {
        if( isUnwinding )
        {
            hold.release();
            return false;
        }

        if( !list.add( hold )) throw new IllegalStateException();

        return true;
    }



    public boolean isUnwinding() { return isUnwinding; }


        private boolean isUnwinding;



    public boolean unwind() { return unwind( CATCHER_0 ); }



    public boolean unwind( final Catcher<Hold> catcher )
    {
        if( isUnwinding ) return false;

        if( catcher == null ) throw new NullPointerException();

        isUnwinding = true;
        while( !list.isEmpty() )
        {
            Hold hold = list.removeLast();
            try{ hold.release(); }
            catch( Error r ) { catcher.catchError( hold, r ); }
            catch( Exception x ) { catcher.catchException( hold, x ); }
        }
        return true;
    }



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


    private final LinkedList<Hold> list = new LinkedList<Hold>();
      // Composing in the list.  This is better than subclassing it, because LinkedList
      // has multiple add() methods and the behaviour of this implementation's overrides
      // would depend on which (if any) the superclass was calling into.  E.g. the add()
      // implementation of GWT (2.1) calls addLast().



}