com.google.common.graph.IncidentEdgeSet Maven / Gradle / Ivy
/*
* Copyright (C) 2019 The Guava Authors
*
* Licensed 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 com.google.common.graph;
import java.util.AbstractSet;
import java.util.Set;
import javax.annotation.CheckForNull;
/**
* Abstract base class for an incident edges set that allows different implementations of {@link
* AbstractSet#iterator()}.
*/
@ElementTypesAreNonnullByDefault
abstract class IncidentEdgeSet extends AbstractSet> {
final N node;
final BaseGraph graph;
IncidentEdgeSet(BaseGraph graph, N node) {
this.graph = graph;
this.node = node;
}
@Override
public boolean remove(@CheckForNull Object o) {
throw new UnsupportedOperationException();
}
@Override
public int size() {
if (graph.isDirected()) {
return graph.inDegree(node)
+ graph.outDegree(node)
- (graph.successors(node).contains(node) ? 1 : 0);
} else {
return graph.adjacentNodes(node).size();
}
}
@Override
public boolean contains(@CheckForNull Object obj) {
if (!(obj instanceof EndpointPair)) {
return false;
}
EndpointPair endpointPair = (EndpointPair) obj;
if (graph.isDirected()) {
if (!endpointPair.isOrdered()) {
return false;
}
Object source = endpointPair.source();
Object target = endpointPair.target();
return (node.equals(source) && graph.successors(node).contains(target))
|| (node.equals(target) && graph.predecessors(node).contains(source));
} else {
if (endpointPair.isOrdered()) {
return false;
}
Set adjacent = graph.adjacentNodes(node);
Object nodeU = endpointPair.nodeU();
Object nodeV = endpointPair.nodeV();
return (node.equals(nodeV) && adjacent.contains(nodeU))
|| (node.equals(nodeU) && adjacent.contains(nodeV));
}
}
}