Java新手备忘录[3]：复杂数据类型的比较

import java.util.TreeSet;

public class Graphnode implements Comparable<Graphnode> {

private String label;
private TreeSet<Graphnode> successors;

public Graphnode(String label) {
this.label = label;
successors = new TreeSet<Graphnode>();
}

public void addSuccessor(Graphnode successor) {
this.successors.add(successor);
}

public String getLabel() {
return label;
}

public TreeSet<Graphnode> getSuccessors() {
return successors;
}

public int compareTo(Graphnode o) {
return this.label.compareTo(o.getLabel());
}
}