I'm trying to store a Person class object in a TreeMap whose constructor takes a Comparator argument. The comparator compares two persons objects on the basis of first name and stores them. But this gives a ClassCastException. How can I achieve the same. Here is my code:
public class Main {
public static void main(String[] args) {
TreeMap map = new TreeMap(new PersonTest());
map.put("soda", "lime");
map.put("juice", "orange");
map.put("honey", "dabur");
map.put("coke", "coke");
Set set = map.entrySet();
Iterator iterator = set.iterator();
while(iterator.hasNext()){
Map.Entry entry = (Map.Entry) iterator.next();
System.out.println(entry.getKey() + "\t" + entry.getValue());
}
}
}
class PersonTest implements Comparator{
private String firstName;
private String lastName;
/* (non-Javadoc)
* @see java.util.Comparator#compare(java.lang.Object, java.lang.Object)
*/
public int compare(Object aO1, Object aO2) {
// TODO Auto-generated method stub
PersonTest p1 = (PersonTest)aO1;
PersonTest p2 = (PersonTest)aO2;
String s1 = p1.firstName;
String s2 = p2.firstName;
return s1.compareTo(s2);
}
/* (non-Javadoc)
* @see java.lang.Object#equals(java.lang.Object)
*/
@Override
public boolean equals(Object aObj) {
// TODO Auto-generated method stub
String s = (String)aObj;
//PersonTest p = (PersonTest)aObj;
return compare(this, s)==0;
}
}
