001package 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. 002 003import java.util.*; 004import votorola.g.lang.Catcher; 005 006 007/** An implementation of a spool based on a linked list. 008 */ 009public final class Spool1 implements Spool 010{ 011 012 013 // - S p o o l ------------------------------------------------------------------------ 014 015 016 public boolean add( Hold hold ) 017 { 018 if( isUnwinding ) 019 { 020 hold.release(); 021 return false; 022 } 023 024 if( !list.add( hold )) throw new IllegalStateException(); 025 026 return true; 027 } 028 029 030 031 public boolean isUnwinding() { return isUnwinding; } 032 033 034 private boolean isUnwinding; 035 036 037 038 public boolean unwind() { return unwind( CATCHER_0 ); } 039 040 041 042 public boolean unwind( final Catcher<Hold> catcher ) 043 { 044 if( isUnwinding ) return false; 045 046 if( catcher == null ) throw new NullPointerException(); 047 048 isUnwinding = true; 049 while( !list.isEmpty() ) 050 { 051 Hold hold = list.removeLast(); 052 try{ hold.release(); } 053 catch( Error r ) { catcher.catchError( hold, r ); } 054 catch( Exception x ) { catcher.catchException( hold, x ); } 055 } 056 return true; 057 } 058 059 060 061//// P r i v a t e /////////////////////////////////////////////////////////////////////// 062 063 064 private final LinkedList<Hold> list = new LinkedList<Hold>(); 065 // Composing in the list. This is better than subclassing it, because LinkedList 066 // has multiple add() methods and the behaviour of this implementation's overrides 067 // would depend on which (if any) the superclass was calling into. E.g. the add() 068 // implementation of GWT (2.1) calls addLast(). 069 070 071 072}