153 * nodes.
154 */
155 public boolean hasOrdering(E preferred, E other) {
156 DigraphNode<E> preferredPONode = poNodes.get(preferred);
157 DigraphNode<E> otherPONode = poNodes.get(other);
158
159 return preferredPONode.hasEdge(otherPONode);
160 }
161 }
162
163 class PartialOrderIterator<E> implements Iterator<E> {
164
165 LinkedList<DigraphNode<E>> zeroList = new LinkedList<>();
166 Map<DigraphNode<E>, Integer> inDegrees = new HashMap<>();
167
168 public PartialOrderIterator(Iterator<DigraphNode<E>> iter) {
169 // Initialize scratch in-degree values, zero list
170 while (iter.hasNext()) {
171 DigraphNode<E> node = iter.next();
172 int inDegree = node.getInDegree();
173 inDegrees.put(node, new Integer(inDegree));
174
175 // Add nodes with zero in-degree to the zero list
176 if (inDegree == 0) {
177 zeroList.add(node);
178 }
179 }
180 }
181
182 public boolean hasNext() {
183 return !zeroList.isEmpty();
184 }
185
186 public E next() {
187 DigraphNode<E> first = zeroList.removeFirst();
188
189 // For each out node of the output node, decrement its in-degree
190 Iterator<DigraphNode<E>> outNodes = first.getOutNodes();
191 while (outNodes.hasNext()) {
192 DigraphNode<E> node = outNodes.next();
193 int inDegree = inDegrees.get(node).intValue() - 1;
194 inDegrees.put(node, new Integer(inDegree));
195
196 // If the in-degree has fallen to 0, place the node on the list
197 if (inDegree == 0) {
198 zeroList.add(node);
199 }
200 }
201
202 return first.getData();
203 }
204
205 public void remove() {
206 throw new UnsupportedOperationException();
207 }
208 }
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153 * nodes.
154 */
155 public boolean hasOrdering(E preferred, E other) {
156 DigraphNode<E> preferredPONode = poNodes.get(preferred);
157 DigraphNode<E> otherPONode = poNodes.get(other);
158
159 return preferredPONode.hasEdge(otherPONode);
160 }
161 }
162
163 class PartialOrderIterator<E> implements Iterator<E> {
164
165 LinkedList<DigraphNode<E>> zeroList = new LinkedList<>();
166 Map<DigraphNode<E>, Integer> inDegrees = new HashMap<>();
167
168 public PartialOrderIterator(Iterator<DigraphNode<E>> iter) {
169 // Initialize scratch in-degree values, zero list
170 while (iter.hasNext()) {
171 DigraphNode<E> node = iter.next();
172 int inDegree = node.getInDegree();
173 inDegrees.put(node, inDegree);
174
175 // Add nodes with zero in-degree to the zero list
176 if (inDegree == 0) {
177 zeroList.add(node);
178 }
179 }
180 }
181
182 public boolean hasNext() {
183 return !zeroList.isEmpty();
184 }
185
186 public E next() {
187 DigraphNode<E> first = zeroList.removeFirst();
188
189 // For each out node of the output node, decrement its in-degree
190 Iterator<DigraphNode<E>> outNodes = first.getOutNodes();
191 while (outNodes.hasNext()) {
192 DigraphNode<E> node = outNodes.next();
193 int inDegree = inDegrees.get(node).intValue() - 1;
194 inDegrees.put(node, inDegree);
195
196 // If the in-degree has fallen to 0, place the node on the list
197 if (inDegree == 0) {
198 zeroList.add(node);
199 }
200 }
201
202 return first.getData();
203 }
204
205 public void remove() {
206 throw new UnsupportedOperationException();
207 }
208 }
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