1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
|
/*******************************************************************************
* Copyright (c) 2010-2012, Tamas Szabo, Istvan Rath and Daniel Varro
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v. 2.0 which is available at
* http://www.eclipse.org/legal/epl-v20.html.
*
* SPDX-License-Identifier: EPL-2.0
*******************************************************************************/
package tools.refinery.viatra.runtime.rete.itc.alg.counting;
import java.util.List;
import java.util.Set;
import tools.refinery.viatra.runtime.rete.itc.alg.misc.DFSPathFinder;
import tools.refinery.viatra.runtime.rete.itc.alg.misc.IGraphPathFinder;
import tools.refinery.viatra.runtime.rete.itc.alg.misc.ITcRelation;
import tools.refinery.viatra.runtime.rete.itc.igraph.IBiDirectionalGraphDataSource;
import tools.refinery.viatra.runtime.rete.itc.igraph.IBiDirectionalWrapper;
import tools.refinery.viatra.runtime.rete.itc.igraph.IGraphDataSource;
import tools.refinery.viatra.runtime.rete.itc.igraph.IGraphObserver;
import tools.refinery.viatra.runtime.rete.itc.igraph.ITcDataSource;
import tools.refinery.viatra.runtime.rete.itc.igraph.ITcObserver;
import tools.refinery.viatra.runtime.matchers.util.CollectionsFactory;
import tools.refinery.viatra.runtime.matchers.util.IMemoryView;
/**
* This class is the optimized implementation of the Counting algorithm.
*
* @author Tamas Szabo
*
* @param <V>
* the type parameter of the nodes in the graph data source
*/
public class CountingAlg<V> implements IGraphObserver<V>, ITcDataSource<V> {
private CountingTcRelation<V> tc = null;
private IBiDirectionalGraphDataSource<V> gds = null;
private List<ITcObserver<V>> observers;
/**
* Constructs a new Counting algorithm and initializes the transitive closure relation with the given graph data
* source. Attach itself on the graph data source as an observer.
*
* @param gds
* the graph data source instance
*/
public CountingAlg(IGraphDataSource<V> gds) {
if (gds instanceof IBiDirectionalGraphDataSource<?>) {
this.gds = (IBiDirectionalGraphDataSource<V>) gds;
} else {
this.gds = new IBiDirectionalWrapper<V>(gds);
}
observers = CollectionsFactory.<ITcObserver<V>>createObserverList();
tc = new CountingTcRelation<V>(true);
initTc();
gds.attachObserver(this);
}
/**
* Initializes the transitive closure relation.
*/
private void initTc() {
this.setTcRelation(CountingTcRelation.createFrom(gds));
}
@Override
public void edgeInserted(V source, V target) {
if (!source.equals(target)) {
deriveTc(source, target, true);
}
}
@Override
public void edgeDeleted(V source, V target) {
if (!source.equals(target)) {
deriveTc(source, target, false);
}
}
@Override
public void nodeInserted(V n) {
}
@Override
public void nodeDeleted(V n) {
this.tc.deleteTupleEnd(n);
}
/**
* Derives the transitive closure relation when an edge is inserted or deleted.
*
* @param source
* the source of the edge
* @param target
* the target of the edge
* @param dCount
* the value is -1 if an edge was deleted and +1 if an edge was inserted
*/
private void deriveTc(V source, V target, boolean isInsertion) {
// if (dCount == 1 && isReachable(target, source)) {
// System.out.println("The graph contains cycle with (" + source + ","+ target + ") edge!");
// }
CountingTcRelation<V> dtc = new CountingTcRelation<V>(false);
Set<V> tupEnds = null;
// 1. d(tc(x,y)) :- d(l(x,y))
if (tc.updateTuple(source, target, isInsertion)) {
dtc.updateTuple(source, target, true /* deltas implicitly have the same sign as isInsertion*/);
notifyTcObservers(source, target, isInsertion);
}
// 2. d(tc(x,y)) :- d(l(x,z)) & tc(z,y)
tupEnds = tc.getTupleEnds(target);
if (tupEnds != null) {
for (V tupEnd : tupEnds) {
if (!tupEnd.equals(source)) {
if (tc.updateTuple(source, tupEnd, isInsertion)) {
dtc.updateTuple(source, tupEnd, true /* deltas implicitly have the same sign as isInsertion*/);
notifyTcObservers(source, tupEnd, isInsertion);
}
}
}
}
// 3. d(tc(x,y)) :- lv(x,z) & d(tc(z,y))
CountingTcRelation<V> newTuples = dtc;
CountingTcRelation<V> tmp = null;
dtc = new CountingTcRelation<V>(false);
IMemoryView<V> nodes = null;
while (!newTuples.isEmpty()) {
tmp = dtc;
dtc = newTuples;
newTuples = tmp;
newTuples.clear();
for (V tS : dtc.getTupleStarts()) {
nodes = gds.getSourceNodes(tS);
for (V nS : nodes.distinctValues()) {
int count = nodes.getCount(nS);
for (int i = 0; i < count; i++) {
tupEnds = dtc.getTupleEnds(tS);
if (tupEnds != null) {
for (V tT : tupEnds) {
if (!nS.equals(tT)) {
if (tc.updateTuple(nS, tT, isInsertion)) {
newTuples.updateTuple(nS, tT, true /* deltas implicitly have the same sign as isInsertion*/);
notifyTcObservers(nS, tT, isInsertion);
}
}
}
}
}
}
}
}
// System.out.println(tc);
}
public ITcRelation<V> getTcRelation() {
return this.tc;
}
public void setTcRelation(CountingTcRelation<V> tc) {
this.tc = tc;
}
@Override
public boolean isReachable(V source, V target) {
return tc.containsTuple(source, target);
}
@Override
public void attachObserver(ITcObserver<V> to) {
this.observers.add(to);
}
@Override
public void detachObserver(ITcObserver<V> to) {
this.observers.remove(to);
}
@Override
public Set<V> getAllReachableTargets(V source) {
return tc.getTupleEnds(source);
}
@Override
public Set<V> getAllReachableSources(V target) {
return tc.getTupleStarts(target);
}
private void notifyTcObservers(V source, V target, boolean isInsertion) {
if (isInsertion) {
for (ITcObserver<V> o : observers) {
o.tupleInserted(source, target);
}
} else {
for (ITcObserver<V> o : observers) {
o.tupleDeleted(source, target);
}
}
}
@Override
public void dispose() {
tc.clear();
this.gds.detachObserver(this);
}
@Override
public IGraphPathFinder<V> getPathFinder() {
return new DFSPathFinder<V>(gds, this);
}
}
|
