org.josef.util

Class CComparator<T extends Comparable<? super T>>

java.lang.Object

org.josef.util.CComparator<T>

Type Parameters:

T - The type of the Objects to compare.

All Implemented Interfaces:

Serializable, Comparator<T>

@Status(stage=PRODUCTION,
        unitTests=PARTIAL)
 @Review(by="Kees Schotanus",
        at="2009-09-28")
public final class CComparator<T extends Comparable<? super T>>
extends Object
implements Comparator<T>, Serializable

Generic Comparator Class for objects that are already Comparable.
The difference between this comparator and the comparators from Sun is that this comparator handles comparison of null values plus ascending/descending order.

Version:

1.0 $Revision: 6488 $

Author:

Kees Schotanus

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	CComparator.OrderNulls Determines whether Null values are ordered high or low.

Constructor Summary

Constructors

Constructor and Description
CComparator() Constructs this Comparator that compares two objects of type <T>.
CComparator(Order order) Constructs this Comparator that compares two objects of type <T>.
CComparator(Order order, CComparator.OrderNulls orderNulls) Constructs this Comparator that compares two objects of type <T>.

Method Summary

Modifier and Type	Method and Description
int	compare(T left, T right) Utility method to compare two objects of type <T>.
static <T extends Comparable<? super T>> int	compareAllowingNulls(T left, T right) Utility method to compare two objects.
static <T extends Comparable<? super T>> int	compareAllowingNulls(T left, T right, Order order) Utility method to compare two objects.
static <T extends Comparable<? super T>> int	compareAllowingNulls(T left, T right, Order order, CComparator.OrderNulls orderNulls) Utility method to compare two objects.
static int	compareStringsIgnoringCase(String stringLeft, String stringRight) Utility method to compare two Strings, ignoring case, while allowing for null Strings.
Order	getOrdering() Gets the order of non-null values.
CComparator.OrderNulls	getOrderNulls() Gets the order of null values.

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

comparing, comparing, comparingDouble, comparingInt, comparingLong, equals, naturalOrder, nullsFirst, nullsLast, reversed, reverseOrder, thenComparing, thenComparing, thenComparing, thenComparingDouble, thenComparingInt, thenComparingLong

Constructor Detail

CComparator

public CComparator()

Constructs this Comparator that compares two objects of type <T>.
Null values are ordered after non-null values and non-null values are ordered ascending.

CComparator

public CComparator(Order order)

Constructs this Comparator that compares two objects of type <T>.

Parameters:

order - Determines whether objects are ordered ascending or descending.

Throws:

NullPointerException - When the supplied order is null.

CComparator

public CComparator(Order order,
                   CComparator.OrderNulls orderNulls)

Constructs this Comparator that compares two objects of type <T>.

Parameters:

order - Determines whether objects are ordered ascending or descending.

orderNulls - Determines whether null values are ordered high or low.

Throws:

NullPointerException - When either the supplied order or orderNulls is null.

Method Detail

getOrdering

public Order getOrdering()

Gets the order of non-null values.

Returns:

True when non-null values are ordered ascending, false when descending.

getOrderNulls

public CComparator.OrderNulls getOrderNulls()

Gets the order of null values.

Returns:

The order of null values.

compare

public int compare(T left,
                   T right)

Utility method to compare two objects of type <T>.

Specified by:

compare in interface Comparator<T extends Comparable<? super T>>

Parameters:

left - The Object on the left.

right - The Object on the right.

Returns:

-1 (left < right), 0 (left == right) or 1 (left > right).

compareAllowingNulls

public static <T extends Comparable<? super T>> int compareAllowingNulls(T left,
                                                                         T right)

Utility method to compare two objects.
Non-null values are ordered ascending and null values are ordered high.

Type Parameters:

T - Type of the objects to compare.

Parameters:

left - The Object on the left.

right - The Object on the right.

Returns:

-1 (left < right), 0 (left == right) or 1 (left > right).

compareAllowingNulls

public static <T extends Comparable<? super T>> int compareAllowingNulls(T left,
                                                                         T right,
                                                                         Order order)

Utility method to compare two objects.
Null values are ordered high.

Type Parameters:

T - Type of the objects to compare.

Parameters:

left - The Object on the left.

right - The Object on the right.

order - Determines whether non-null values are ordered ascending or descending.
This parameter should not be null but for performance reasons no explicit check is performed to enforce this.

Returns:

-1 (left < right), 0 (left == right) or 1 (left > right).

compareAllowingNulls

public static <T extends Comparable<? super T>> int compareAllowingNulls(T left,
                                                                         T right,
                                                                         Order order,
                                                                         CComparator.OrderNulls orderNulls)

Utility method to compare two objects.

Type Parameters:

T - Type of the object to compare to this one.

Parameters:

left - The Object on the left.

right - The Object on the right.

order - Determines whether non-null values are ordered ascending or descending. The order should not be null but for performance reasons no explicit check is performed.

orderNulls - Determines whether null values are ordered after non-null values or before non-null values.
This parameter should not be null but for performance reasons no explicit check is performed to enforce this.

Returns:

-1 (left < right), 0 (left == right) or 1 (left > right).

compareStringsIgnoringCase

public static int compareStringsIgnoringCase(String stringLeft,
                                             String stringRight)

Utility method to compare two Strings, ignoring case, while allowing for null Strings.

Parameters:

stringLeft - The String on the left.

stringRight - The String on the right.

Returns:

-1 (left < right), 0 (left == right) or 1 (left > right).