com.helger.commons.compare

Class AbstractComparator<DATATYPE>

java.lang.Object

com.helger.commons.compare.AbstractComparator<DATATYPE>

Type Parameters:

DATATYPE - The data type to be compared

All Implemented Interfaces:

ISerializableComparator<DATATYPE>, Serializable, Comparator<DATATYPE>

Direct Known Subclasses:

AbstractBigDecimalComparator, AbstractDoubleComparator, AbstractFloatComparator, AbstractIntComparator, AbstractLongComparator, AbstractPartComparator, AbstractPartComparatorComparable, CollatingComparator, ComparatorChangeLogEntryDateAndComponent, ComparatorComparable, ComparatorQName, ComparatorStringCaseInsensitve, ComparatorStringLongestFirst, ComparatorStringShortestFirst

@NotThreadSafe
public abstract class AbstractComparator<DATATYPE>
extends Object
implements ISerializableComparator<DATATYPE>

Abstract comparator class that supports a sort order and a nested comparator.

Author:

Philip Helger

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
AbstractComparator() Comparator with default sort order and no nested comparator.

Method Summary

Modifier and Type	Method and Description
int	compare(DATATYPE aElement1, DATATYPE aElement2)
Comparator<? super DATATYPE>	getNestedComparator()
ESortOrder	getSortOrder()
boolean	isNullValuesComeFirst()
protected abstract int	mainCompare(DATATYPE aElement1, DATATYPE aElement2)
AbstractComparator<DATATYPE>	setNestedComparator(Comparator<? super DATATYPE> aNestedComparator) Set a nested comparator to be invoked if the comparison result of this comparator is 0.
AbstractComparator<DATATYPE>	setNullValuesComeFirst(boolean bNullValuesComeFirst) Change the sort position of null values.
AbstractComparator<DATATYPE>	setSortOrder(ESortOrder eSortOrder) Call this to enable sorting after the constructor was invoked.
String	toString()

Methods inherited from class java.lang.Object

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

AbstractComparator

public AbstractComparator()

Comparator with default sort order and no nested comparator.

Method Detail

getSortOrder

@Nonnull
public final ESortOrder getSortOrder()

Returns:

The currently assigned sort order. Never null.

setSortOrder

@Nonnull
public final AbstractComparator<DATATYPE> setSortOrder(@Nonnull
                                                                 ESortOrder eSortOrder)

Call this to enable sorting after the constructor was invoked.

Parameters:

eSortOrder - The sort order to use. May not be null.

Returns:

this

isNullValuesComeFirst

public final boolean isNullValuesComeFirst()

Returns:

true if null values are to be ordered before non-null values, false if null are to be sorted after non-null values.

setNullValuesComeFirst

@Nonnull
public final AbstractComparator<DATATYPE> setNullValuesComeFirst(boolean bNullValuesComeFirst)

Change the sort position of null values.

Parameters:

bNullValuesComeFirst - true if null values should come first, false if null values should go last.

Returns:

this

getNestedComparator

@Nonnull
public final Comparator<? super DATATYPE> getNestedComparator()

Returns:

The nested comparator. May be null.

setNestedComparator

@Nonnull
public final AbstractComparator<DATATYPE> setNestedComparator(@Nullable
                                                                        Comparator<? super DATATYPE> aNestedComparator)

Set a nested comparator to be invoked if the comparison result of this comparator is 0.

Parameters:

aNestedComparator - The nested comparator to be invoked, when the main comparison resulted in 0. May be null.

Returns:

this

mainCompare

protected abstract int mainCompare(@Nonnull
                                   DATATYPE aElement1,
                                   @Nonnull
                                   DATATYPE aElement2)

Parameters:

aElement1 - First element to compare. Never null.

aElement2 - Second element to compare. Never null.

Returns:

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

compare

public final int compare(DATATYPE aElement1,
                         DATATYPE aElement2)

Specified by:

compare in interface Comparator<DATATYPE>

toString

public String toString()

Overrides:

toString in class Object