| package org.onlab.graph; |
| |
| import com.google.common.collect.ImmutableList; |
| |
| import java.util.ArrayList; |
| import java.util.List; |
| import java.util.Objects; |
| |
| import static com.google.common.base.MoreObjects.toStringHelper; |
| import static com.google.common.base.Preconditions.checkArgument; |
| import static com.google.common.base.Preconditions.checkNotNull; |
| |
| /** |
| * Simple concrete implementation of a directed graph path. |
| */ |
| public class DefaultMutablePath<V extends Vertex, E extends Edge<V>> implements MutablePath<V, E> { |
| |
| private final List<E> edges = new ArrayList<>(); |
| private double cost = 0.0; |
| |
| /** |
| * Creates a new empty path. |
| */ |
| public DefaultMutablePath() { |
| } |
| |
| /** |
| * Creates a new path as a copy of another path. |
| * |
| * @param path path to be copied |
| */ |
| public DefaultMutablePath(Path<V, E> path) { |
| checkNotNull(path, "Path cannot be null"); |
| this.cost = path.cost(); |
| edges.addAll(path.edges()); |
| } |
| |
| @Override |
| public V src() { |
| return edges.isEmpty() ? null : edges.get(0).src(); |
| } |
| |
| @Override |
| public V dst() { |
| return edges.isEmpty() ? null : edges.get(edges.size() - 1).dst(); |
| } |
| |
| @Override |
| public double cost() { |
| return cost; |
| } |
| |
| @Override |
| public List<E> edges() { |
| return ImmutableList.copyOf(edges); |
| } |
| |
| @Override |
| public void setCost(double cost) { |
| this.cost = cost; |
| } |
| |
| @Override |
| public Path<V, E> toImmutable() { |
| return new DefaultPath<>(edges, cost); |
| } |
| |
| @Override |
| public void insertEdge(E edge) { |
| checkNotNull(edge, "Edge cannot be null"); |
| checkArgument(edges.isEmpty() || src().equals(edge.dst()), |
| "Edge destination must be the same as the current path source"); |
| edges.add(0, edge); |
| } |
| |
| @Override |
| public void appendEdge(E edge) { |
| checkNotNull(edge, "Edge cannot be null"); |
| checkArgument(edges.isEmpty() || dst().equals(edge.src()), |
| "Edge source must be the same as the current path destination"); |
| edges.add(edge); |
| } |
| |
| @Override |
| public void removeEdge(E edge) { |
| checkArgument(edge.src().equals(edge.dst()) || |
| edges.indexOf(edge) == 0 || |
| edges.lastIndexOf(edge) == edges.size() - 1, |
| "Edge must be at start or end of path, or it must be a cyclic edge"); |
| edges.remove(edge); |
| } |
| |
| @Override |
| public String toString() { |
| return toStringHelper(this) |
| .add("src", src()) |
| .add("dst", dst()) |
| .add("cost", cost) |
| .add("edges", edges) |
| .toString(); |
| } |
| |
| @Override |
| public int hashCode() { |
| return Objects.hash(edges, cost); |
| } |
| |
| @Override |
| public boolean equals(Object obj) { |
| if (this == obj) { |
| return true; |
| } |
| if (obj instanceof DefaultMutablePath) { |
| final DefaultMutablePath other = (DefaultMutablePath) obj; |
| return Objects.equals(this.cost, other.cost) && |
| Objects.equals(this.edges, other.edges); |
| } |
| return false; |
| } |
| |
| } |