jgrapht-users

[jgrapht-users] The code

[Vernon S. <vwu...@ly...>]

Hi, Barak,

The enclosed is the code for the problems I posted on JGraphT forum. The class layout is my original approach with a custom Vertex class, which is not the one in my application, but it yields the same exception. Please let me know hot to fix the problem.

Many thinks.

Vernon





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RE: [jgrapht-users] The code

[Barak N. <bar...@us...>]

Hi Vernon,=20

The problem is in your implementation of class V.

The class overrides the equals() method without overriding hashCode()
method. Doing it is against the contract of equals() and hashCode() =
methods,
and it confuses the HashSet class used internally by JGraphT.

This is a mistake that almost every Java programmer does only once. I'm
saying "once" because it usually takes enough time to find, to never =
forget
about it :).

Please read CAREFULLY the documentation of equals() and hashCode():
http://java.sun.com/j2se/1.4.2/docs/api/java/lang/Object.html

The answers are coming ... ;)

All the best,
Barak


> -----Original Message-----
> From: jgr...@li... [mailto:jgrapht-users-
> ad...@li...] On Behalf Of Vernon Smith
> Sent: Thursday, October 23, 2003 02:45
> To: jgr...@li...
> Subject: [jgrapht-users] The code
>=20
>=20
> Hi, Barak,
>=20
> The enclosed is the code for the problems I posted on JGraphT forum. =
The
> class layout is my original approach with a custom Vertex class, which =
is
> not the one in my application, but it yields the same exception. =
Please
> let me know hot to fix the problem.
>=20
> Many thinks.
>=20
> Vernon
>=20