/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.drill.common.graph;
import java.util.HashMap;
import java.util.Map;
class AdjacencyListBuilder<V extends GraphValue<V>> implements GraphVisitor<V> {
static final org.slf4j.Logger logger = org.slf4j.LoggerFactory.getLogger(AdjacencyListBuilder.class);
private Map<V, AdjacencyList<V>.Node> ops = new HashMap<V, AdjacencyList<V>.Node>();
private final AdjacencyList<V> parent;
public AdjacencyListBuilder(AdjacencyList<V> parent) {
this.parent = parent;
}
protected boolean requireDirected() {
return true;
}
public boolean enter(V o) {
visit(o);
return true;
}
@Override
public void leave(V o) {
}
@Override
public boolean visit(V o) {
if (o == null) {
throw new IllegalArgumentException("Null operator.");
}
if (!ops.containsKey(o)) {
ops.put(o, parent.getNewNode(o));
return true;
}
return true;
}
public AdjacencyList<V> getAdjacencyList() {
// logger.debug("Values; {}", ops.values().toArray());
AdjacencyList<V> a = new AdjacencyList<V>();
for (AdjacencyList<V>.Node from : ops.values()) {
for (V t : from.getNodeValue()) {
AdjacencyList<V>.Node to = ops.get(t);
a.addEdge(from, to, 0);
}
}
a.fix(true);
return a;
}
}