1 // Copyright 2006-2007 all rights reserved; see LICENSE file for BSD-style license
3 package edu.berkeley.sbp;
4 import edu.berkeley.sbp.util.*;
5 import edu.berkeley.sbp.Sequence.Pos;
6 import edu.berkeley.sbp.Sequence.Pos;
10 extends Node<StateNode> {
12 private Forest.Many f = new Forest.Many();
13 private boolean destroyed = false;
14 private boolean primordeal;
15 private int usedByNonDoomedNode = 0;
16 private Pos reduction;
17 private GSS.Phase predPhase;
19 public Pos reduction() { return reduction; }
20 public void merge(Forest newf) {
23 if (predecessors.contains(pred)) return;
25 if (fromEmptyReduction) return;
26 n.state().invokeReductions(n.phase().getToken(), n, this);
30 public GSS.Phase phase() { return predPhase; }
31 public Forest getForest() { return f; }
32 public void addSucc(StateNode succ) {
33 if (successors.contains(succ)) return;
35 usedByNonDoomedNode += succ.state().doomed ? 0 : 1;
36 if (predecessors.size() > 1) throw new Error();
38 public void removeSucc(StateNode succ) {
39 if (!successors.contains(succ)) return;
40 successors.remove(succ);
41 usedByNonDoomedNode -= succ.state().doomed ? 0 : 1;
45 public boolean usedByAnyNode() { return successors.size() > 0; }
46 public boolean usedByNonDoomedNode() { return usedByNonDoomedNode > 0; }
48 public String toString() { return super.toString()+"->"+predPhase; }
51 if (successors.size()==0) destroy();
52 else if (predecessors.size()==0) destroy();
54 public void destroy() {
55 if (destroyed) return;
56 if (primordeal) return; // never destroy the "primordeal" result
58 while(predecessors.size() > 0)
59 for(StateNode pred : predecessors) {
61 pred.removeSucc(this);
65 while(successors.size() > 0)
66 for(StateNode succ : successors) {
68 succ.removePred(this);
74 public void removePred(StateNode pred) {
75 if (!predecessors.contains(pred)) return;
76 predecessors.remove(pred);
80 public void addPred(StateNode pred) {
81 if (predPhase==null) predPhase = pred.phase();
82 if (predPhase != pred.phase()) throw new Error();
83 predecessors.add(pred);
85 if (predecessors.size() > 1) throw new Error();
89 this(null, null, null);
90 this.primordeal = true;
92 public ResultNode(Forest f, Pos reduction, StateNode pred) {
94 this.reduction = reduction;
95 if (pred != null) addPred(pred);