Find if there is a path between two vertices in a directed graph

public enum State {  
    Unvisited, Visited, Visiting;  
}  
   
public static boolean search(Graph g, Node start, Node end) {  
    LinkedList<Node> q = new LinkedList<Node>(); // operates as Stack  
    for (Node u : g.getNodes()) {  
        u.state = State.Unvisited;  
    }  
    start.state = State.Visiting;  
    q.add(start);  
    Node u;  
    while (!q.isEmpty()) {  
        u = q.removeFirst(); // i.e., pop()  
        if (u != null) {  
            for (Node v : u.getAdjacent()) {  
                if (v.state == State.Unvisited) {  
                    if (v == end) {  
                        return true;  
                    } else {  
                        v.state = State.Visiting;  
                        q.add(v);  
                    }  
                }  
            }  
            u.state = State.Visited;  
        }  
    }  
    return false;  
}  

public static boolean isRouteBetween(Digraph g, Integer start, Integer end) {  
    Stack<Integer> stack = new Stack<Integer>();  
    Set<Integer> visited = new HashSet<Integer>();  
    if (start != null) {  
        stack.push(start);  
   
        while (!stack.isEmpty()) {  
            Integer curr = stack.pop();  
            if (!visited.contains(curr)) {  
                if (curr.equals(end))  
                    return true;  
                else {  
                    visited.add(curr);  
                    for (Integer child : g.adj(curr))  
                        stack.push(child);  
                }  
            }  
        }  
    }  
    return false;  
}