Interface LongComparator
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public interface LongComparator
A comparison function which imposes a total ordering on some collection of elements. Comparators can be passed to a sort method (such ascern.colt.Sorting.quickSort
) to allow precise control over the sort order.Note: It is generally a good idea for comparators to implement
java.io.Serializable
, as they may be used as ordering methods in serializable data structures. In order for the data structure to serialize successfully, the comparator (if provided) must implementSerializable
.- Version:
- 0.1 01/09/99
- Author:
- wolfgang.hoschek@cern.ch
- See Also:
Comparator
,Sorting
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description int
compare(long o1, long o2)
Compares its two arguments for order.boolean
equals(Object obj)
Indicates whether some other object is "equal to" this Comparator.
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Method Detail
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compare
int compare(long o1, long 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 allx
andy
. (This implies thatcompare(x, y)
must throw an exception if and only ifcompare(y, x)
throws an exception.)The implementor must also ensure that the relation is transitive:
((compare(x, y)>0) && (compare(y, z)>0))
impliescompare(x, z)>0
.Finally, the implementer must ensure that
compare(x, y)==0
implies thatsgn(compare(x, z))==sgn(compare(y, z))
for allz
.- Returns:
- a negative integer, zero, or a positive integer as the first argument is less than, equal to, or greater than the second.
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equals
boolean equals(Object obj)
Indicates whether some other object is "equal to" this Comparator. This method must obey the general contract ofObject.equals(Object)
. Additionally, this method can returntrue
only if the specified Object is also a comparator and it imposes the same ordering as this comparator. Thus,comp1.equals(comp2)
implies thatsgn(comp1.compare(o1, o2))==sgn(comp2.compare(o1, o2))
for every elemento1
ando2
.Note that it is always safe not to override
Object.equals(Object)
. However, overriding this method may, in some cases, improve performance by allowing programs to determine that two distinct Comparators impose the same order.- Overrides:
equals
in classObject
- Parameters:
obj
- the reference object with which to compare.- Returns:
true
only if the specified object is also a comparator and it imposes the same ordering as this comparator.- See Also:
Object.equals(java.lang.Object)
,Object.hashCode()
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