Package org.apache.sis.internal.filter

Class SortByComparator<R>

java.lang.Object

org.apache.sis.internal.filter.SortByComparator<R>

Type Parameters:

R - the type of resources (typically Feature) to sort.

All Implemented Interfaces:

Serializable, Comparator<R>, SortBy<R>

public final class SortByComparator<R>
extends Object
implements SortBy<R>, Serializable

Comparator sorting features using an array of SortProperty elements applied in order.

Since:

1.0

Version:

1.1

See Also:

• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
private final SortProperty<R>[]	properties	The sort order specified to the constructor.
private static final long	serialVersionUID	For cross-version compatibility.

Constructor Summary

Constructors

Modifier	Constructor	Description
private	SortByComparator(Map<?,SortProperty<R>> merged)	Creates a new comparator with the values of given map.
private	SortByComparator(SortProperty<R> p)	Creates a new comparator for the given sort expression.

Method Summary

Modifier and Type	Method	Description
private static <R> void	addAll(List<SortProperty<R>> properties, Map<ValueReference<? super R,?>,SortProperty<R>> merged)	Adds all elements of the properties list into the merged map.
int	compare(R r1, R r2)	Compares two resources for order.
static <R> SortBy<? super R>	concatenate(SortBy<? super R> sort, Comparator<? super R> comparator)	Creates a new comparator as the concatenation of the two given comparators.
static <R> SortBy<R>	concatenate(SortBy<R> s1, SortBy<R> s2)	Creates a new comparator as the concatenation of the two given comparators.
static <R> SortByComparator<R>	create(SortProperty<R>[] properties)	Creates a new comparator for the given sort expressions.
List<SortProperty<R>>	getSortProperties()	Returns the properties whose values are used for sorting.
Comparator<R>	thenComparing(Comparator<? super R> other)	Returns a comparator as the concatenation of this comparator with the given one.

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, reversed, thenComparing, thenComparing, thenComparingDouble, thenComparingInt, thenComparingLong

Field Details

serialVersionUID

private static final long serialVersionUID

For cross-version compatibility.

See Also:

• Constant Field Values

properties

private final SortProperty<R>[] properties

The sort order specified to the constructor.

See Also:

• getSortProperties()

Constructor Details

SortByComparator

private SortByComparator(SortProperty<R> p)

Creates a new comparator for the given sort expression. This is shortcut for the common case where there is a single expression.

Parameters:

p - the property to wrap in a SortBy comparator.

SortByComparator

private SortByComparator(Map<?,SortProperty<R>> merged)

Creates a new comparator with the values of given map. The map is used for removing duplicated expressions.

Method Details

create

public static <R> SortByComparator<R> create(SortProperty<R>[] properties)

Creates a new comparator for the given sort expressions.

Type Parameters:

R - the type of resources (typically Feature) to sort.

Parameters:

properties - the sort order.

Returns:

the comparator, or null if the given array is empty.

concatenate

public static <R> SortBy<? super R> concatenate(SortBy<? super R> sort,
 Comparator<? super R> comparator)

Creates a new comparator as the concatenation of the two given comparators. The first comparator is used first, and if two resources are equal then the second comparator is used.

Type Parameters:

R - the type of resources (typically Feature) to sort.

Parameters:

sort - the first "sort by" to use, or null if none.

comparator - the second "sort by" to use.

Returns:

concatenation of the two comparators.

concatenate

public static <R> SortBy<R> concatenate(SortBy<R> s1,
 SortBy<R> s2)

Creates a new comparator as the concatenation of the two given comparators. The first comparator is used first, and if two resources are equal then the second comparator is used.

Type Parameters:

R - the type of resources (typically Feature) to sort.

Parameters:

s1 - the first "sort by" to use.

s2 - the second "sort by" to use.

Returns:

concatenation of the two comparators.

addAll

private static <R> void addAll(List<SortProperty<R>> properties,
 Map<ValueReference<? super R,?>,SortProperty<R>> merged)

Adds all elements of the properties list into the merged map. If two SortProperty instances use the same ValueReference, then only the first occurrence is retained.

getSortProperties

public List<SortProperty<R>> getSortProperties()

Returns the properties whose values are used for sorting. The list shall have a minimum of one element.

Specified by:

getSortProperties in interface SortBy<R>

compare

public int compare(R r1,
 R r2)

Compares two resources for order. Returns a negative number if r1 should be sorted before r2, a positive number if r2 should be after r1, or 0 if both resources are equal. The ordering of null resources or null property values is unspecified.

Specified by:

compare in interface Comparator<R>

thenComparing

public Comparator<R> thenComparing(Comparator<? super R> other)

Returns a comparator as the concatenation of this comparator with the given one. This comparator is used first, and if two resources are equal then the other comparator is used.

Specified by:

thenComparing in interface Comparator<R>

Parameters:

other - the other comparator to be used when this comparator considers two resources as equal.

Returns:

concatenation of this comparator with the given one.