Why will TreeMap<K,V>(Comparator) not compile?

[Thomas Kennedy]

The compiler won't let me do this:

import java.util.*;
class mapc implements Comparable<mapc>{

	public static void main(String[] foofy){
		TreeMap m = new TreeMap(new mapsorta());

		m.put(new Integer("13"), new mapc("Arthur"));
		m.put(new Integer("17"), new mapc("Fred"));

		System.out.println("m="+m);

		mapsortd desc = new mapsortd();
		TreeMap<Integer,mapc> d = new TreeMap<Integer,mapc>(desc);
	}

	private String value;

	public mapc(String foofy){this.value=foofy;}

	public String toString(){return this.value;}

	public int compareTo(mapc other){
		return this.toString().compareTo(other.toString());
	}
}

class mapsortd implements Comparator<mapc>{
	public int compare(mapc one, mapc two){
		return two.compareTo(one);
	}
}

It says:

mapc.java:13: cannot find symbol
symbol : constructor TreeMap(mapsortd)
location: class java.util.TreeMap<java.lang.Integer,mapc>
TreeMap<Integer,mapc> d = new TreeMap<Integer,mapc>(desc)
^

It seems TreeMap can use generics, or a Comparator, but not both. I don't quite see why the compiler would object to this. Can anyone explain this?

[Henry Wong]

TreeMap takes a Comparator that compares the keys -- not the values.

Henry

[Thomas Kennedy]

Right, thank you!

TreeMap<Integer, mapx> m = new TreeMap<Integer,mapx>(new mapdesc());

class mapdesc implements Comparator<Integer>