Comparable does not compare

[montechristos]

Hello all,

I am relatively new to JFreeChart...

I am using a DefaultCategoryDataset to populate my graph.
So I created a Comparable for Dates that is:

Code: Select all

	private class ComparableFormattedDate implements Comparable<ComparableFormattedDate> {
		private Date date;
		
		public ComparableFormattedDate(Date date) {
			this.date = date;
		}
		
		@Override
		public String toString() {
			return getFormattedDate(date);
		}

		public int compareTo(ComparableFormattedDate o) {
			int res = date.compareTo(o.date);
			
			System.err.println(String.format("Comparing date %s to %s and got: %d", getFormattedDate(date), getFormattedDate(o.date), res));
			
			return res;
		}
	}

However my compareTo function is never called.
Internally it must be using the == instead of my compareTo method cause if I put the same comparable Objects, it seems to work.

I believe this is a bug, can somebody comment on this?

Thanks in advance

[ahill]

You should probably override equals and hashCode too.

The default implementation in Object is just:

Code: Select all

public boolean equals(Object obj) {
	return (this == obj);

Theres lengthy waffle about the need for consistency between equals, hasCode, and compareTo in the relevant javadocs, so its probably something to do with that.

(I too have burned countless hours tracking down odd collections related issues when I made a mess of implementing Comparable and its associated methods!...)

[smallet]

However my compareTo function is never called

I'm having the same problem. Any news ?

[david.gilbert]

You need to override equals().

[smallet]

thanx for your fast reply.
the problem is that i already overide equals() and hashCode()

could the problem comes from the fact i'm using a DefaultCategoryDataset wich create its data using DefaultKeyedValues2D default constructor wich use false as value for sortRowKeys field ?