/**
* to performe the relaxation between two vertices
*
* @param firstVertex the first vertex
* @param neighbour the neighbouring vertex of the first vertex
* @param weightOfEdge the weight of the edge between the first vertex and the neighbouring vertex
*/
private static void relax(Vertex firstVertex, Vertex neighbour, int weightOfEdge) {
if (neighbour.getDistance() > firstVertex.getDistance() + weightOfEdge) {
neighbour.setDistance(firstVertex.getDistance() + weightOfEdge);
neighbour.setPredecessor(firstVertex);
neighbour.setState(EndStateOfPoint.REACHABLE);
}
}
/**
* initializes the Dijkstra algorithm by setting the start vertex, setting a queue to help
* performing Dijkstra
*
* @param graph the graph in which the Dijkstra algorithm should be performed
* @param startVertexID the start vertex
* @param destinationVertexID the end vertex
*/
public static void initializeDijkstra(
Graph<Vertex, Edge<Vertex>> graph, int startVertexID, int destinationVertexID) {
for (int i = 0; i < graph.getVertices().size(); i++) {
graph.getVertex(i).setDistance(Integer.MAX_VALUE);
graph.getVertex(i).setPredecessor(null);
}
Vertex startVertex = graph.getVertex(startVertexID);
startVertex.setDistance(0);
startVertex.setPredecessor(startVertex);
startVertex.setState(EndStateOfPoint.STARTPOINT);
ArrayList<Vertex> queue = new ArrayList<Vertex>();
for (int i = 0; i < graph.getVertices().size(); i++) {
queue.add(graph.getVertex(i));
}
performeDijkstra(graph, queue, startVertexID, destinationVertexID);
}
