org.riverock.dbrevision.db
Class DbPkComparator

java.lang.Object
  org.riverock.dbrevision.db.DbPkComparator

All Implemented Interfaces:

Serializable, Comparator<DbPrimaryKeyColumn>

public class DbPkComparator
extends Object
implements Comparator<DbPrimaryKeyColumn>, Serializable

Author:

Sergei Maslyukov Date: 28.11.2006 Time: 17:31:51

$Id$

See Also:

Serialized Form

Constructor Summary

DbPkComparator()

Method Summary

int	compare(DbPrimaryKeyColumn o1, DbPrimaryKeyColumn o2) Compares its two arguments for order.
static DbPkComparator	getInstance()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.util.Comparator

equals

Constructor Detail

DbPkComparator

public DbPkComparator()

Method Detail

getInstance

public static DbPkComparator getInstance()

compare

public int compare(DbPrimaryKeyColumn o1,
                   DbPrimaryKeyColumn o2)

Compares its two arguments for order. Returns a negative integer, zero, or a positive integer as the first argument is less than, equal to, or greater than the second.

The implementor must ensure that sgn(compare(x, y)) == -sgn(compare(y, x)) for all x and y. (This implies that compare(x, y) must throw an exception if and only if compare(y, x) throws an exception.)

The implementor must also ensure that the relation is transitive: ((compare(x, y)>0) && (compare(y, z)>0)) implies compare(x, z)>0.

Finally, the implementer must ensure that compare(x, y)==0 implies that sgn(compare(x, z))==sgn(compare(y, z)) for all z.

It is generally the case, but not strictly required that (compare(x, y)==0) == (x.equals(y)). Generally speaking, any comparator that violates this condition should clearly indicate this fact. The recommended language is "Note: this comparator imposes orderings that are inconsistent with equals."

Specified by:

compare in interface Comparator<DbPrimaryKeyColumn>

Parameters:

o1 - the first object to be compared.

o2 - the second object to be compared.

Returns:

a negative integer, zero, or a positive integer as the first argument is less than, equal to, or greater than the second.

Throws:

ClassCastException - if the arguments' types prevent them from being compared by this Comparator.