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 boolean predecessorsContains(StateNode n) {
20 return predecessors.contains(n);
22 public Pos reduction() { return reduction; }
23 public void merge(Forest newf) {
26 if (predecessors.contains(pred)) return;
28 if (fromEmptyReduction) return;
29 n.state().invokeReductions(n.phase().getToken(), n, this);
33 public boolean noSuccessors() { return successors.size()==0; }
35 public GSS.Phase phase() { return predPhase; }
36 public Forest getForest() { return f; }
37 public Iterable<StateNode> getPreds() { return predecessors; }
38 public void addSucc(StateNode succ) {
39 if (successors.contains(succ)) return;
41 usedByNonDoomedNode += succ.state().doomed ? 0 : 1;
42 if (predecessors.size() > 1) throw new Error();
44 public void removeSucc(StateNode succ) {
45 if (!successors.contains(succ)) return;
46 successors.remove(succ);
47 usedByNonDoomedNode -= succ.state().doomed ? 0 : 1;
51 public boolean usedByAnyNode() { return successors.size() > 0; }
52 public boolean usedByNonDoomedNode() { return usedByNonDoomedNode > 0; }
54 public String toString() { return super.toString()+"->"+predPhase; }
57 if (successors.size()==0) destroy();
58 else if (predecessors.size()==0) destroy();
60 public void destroy() {
61 if (destroyed) return;
62 if (primordeal) return; // never destroy the "primordeal" result
64 while(predecessors.size() > 0)
65 for(StateNode pred : predecessors) {
67 pred.removeSucc(this);
71 while(successors.size() > 0)
72 for(StateNode succ : successors) {
74 succ.removeResult(this);
80 public void removePred(StateNode pred) {
81 if (!predecessors.contains(pred)) return;
82 predecessors.remove(pred);
86 public void addPred(StateNode pred) {
87 if (predPhase==null) predPhase = pred.phase();
88 if (predPhase != pred.phase()) throw new Error();
89 predecessors.add(pred);
91 if (predecessors.size() > 1) throw new Error();
95 this(null, null, null);
96 this.primordeal = true;
98 public ResultNode(Forest f, Pos reduction, StateNode pred) {
100 this.reduction = reduction;
101 if (pred != null) addPred(pred);