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/*
* Copyright 2015 Open Networking Laboratory
*
* 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 org.onlab.graph;
import java.util.List;
import java.util.Objects;
import static com.google.common.base.MoreObjects.toStringHelper;
/**
* Pair of disjoint paths.
*
* @param <V> type of vertex
* @param <E> type of edge
*/
public class DisjointPathPair<V extends Vertex, E extends Edge<V>> implements Path<V, E> {
private final Path<V, E> primary, secondary;
private boolean primaryActive = true;
/**
* Creates a disjoint path pair from two paths.
*
* @param primary primary path
* @param secondary secondary path
*/
public DisjointPathPair(Path<V, E> primary, Path<V, E> secondary) {
this.primary = primary;
this.secondary = secondary;
}
@Override
public V src() {
return primary.src();
}
@Override
public V dst() {
return primary.dst();
}
/**
* Returns the primary path.
*
* @return primary path
*/
public Path<V, E> primary() {
return primary;
}
/**
* Returns the secondary path.
*
* @return primary path
*/
public Path<V, E> secondary() {
return secondary;
}
@Override
public double cost() {
return hasBackup() ? primary.cost() + secondary.cost() : primary.cost();
}
@Override
public List<E> edges() {
return primaryActive || !hasBackup() ? primary.edges() : secondary.edges();
}
/**
* Checks if this path pair contains a backup/secondary path.
*
* @return boolean representing whether it has backup
*/
public boolean hasBackup() {
return secondary != null;
}
@Override
public String toString() {
return toStringHelper(this)
.add("src", src())
.add("dst", dst())
.add("cost", cost())
.add("edges", edges())
.toString();
}
@Override
public int hashCode() {
// Note: DisjointPathPair with primary and secondary swapped
// must result in same hashCode
return hasBackup() ? primary.hashCode() + secondary.hashCode() :
Objects.hash(primary);
}
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj instanceof DisjointPathPair) {
final DisjointPathPair other = (DisjointPathPair) obj;
return Objects.equals(this.src(), other.src()) &&
Objects.equals(this.dst(), other.dst()) &&
(Objects.equals(this.primary, other.primary) &&
Objects.equals(this.secondary, other.secondary)) ||
(Objects.equals(this.primary, other.secondary) &&
Objects.equals(this.secondary, other.primary));
}
return false;
}
/**
* Returns number of paths inside this path pair object.
*
* @return number of paths
*/
public int size() {
return hasBackup() ? 2 : 1;
}
}
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