Class OrderComparator
- java.lang.Object
- org.springframework.core.OrderComparator
- All Implemented Interfaces:
Comparator<Object>
- Direct Known Subclasses:
AnnotationAwareOrderComparator
public class OrderComparator extends Object implements Comparator<Object>
Comparatorimplementation forOrderedobjects, sorting by order value ascending, respectively by priority descending.PriorityOrderedObjectsPriorityOrderedobjects will be sorted with higher priority than plainOrderedobjects.Same Order Objects
Objects that have the same order value will be sorted with arbitrary ordering with respect to other objects with the same order value.
Non-ordered Objects
Any object that does not provide its own order value is implicitly assigned a value of
Ordered.LOWEST_PRECEDENCE, thus ending up at the end of a sorted collection in arbitrary order with respect to other objects with the same order value.- Since:
- 07.04.2003
- Author:
- Juergen Hoeller, Sam Brannen
- See Also:
Ordered,PriorityOrdered,AnnotationAwareOrderComparator,List.sort(java.util.Comparator),Arrays.sort(Object[], java.util.Comparator)
Nested Class Summary
Nested Classes Modifier and Type Class Description static interfaceOrderComparator.OrderSourceProviderStrategy interface to provide an order source for a given object.
Field Summary
Fields Modifier and Type Field Description static OrderComparatorINSTANCEShared default instance ofOrderComparator.
Constructor Summary
Constructors Constructor Description OrderComparator()
Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description intcompare(Object o1, Object o2)protected IntegerfindOrder(Object obj)Find an order value indicated by the given object.protected intgetOrder(Object obj)Determine the order value for the given object.IntegergetPriority(Object obj)Determine a priority value for the given object, if any.static voidsort(Object[] array)Sort the given array with a default OrderComparator.static voidsort(List<?> list)Sort the given List with a default OrderComparator.static voidsortIfNecessary(Object value)Sort the given array or List with a default OrderComparator, if necessary.Comparator<Object>withSourceProvider(OrderComparator.OrderSourceProvider sourceProvider)Build an adapted order comparator with the given source provider.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, thenComparing, thenComparingDouble, thenComparingInt, thenComparingLong
Field Detail
INSTANCE
public static final OrderComparator INSTANCE
Shared default instance ofOrderComparator.
Constructor Detail
OrderComparator
public OrderComparator()
Method Detail
withSourceProvider
public Comparator<Object> withSourceProvider(OrderComparator.OrderSourceProvider sourceProvider)
Build an adapted order comparator with the given source provider.- Parameters:
sourceProvider- the order source provider to use- Returns:
- the adapted comparator
- Since:
- 4.1
compare
public int compare(@Nullable Object o1, @Nullable Object o2)
- Specified by:
comparein interfaceComparator<Object>
getOrder
protected int getOrder(@Nullable Object obj)
Determine the order value for the given object.The default implementation checks against the
Orderedinterface through delegating tofindOrder(java.lang.Object). Can be overridden in subclasses.- Parameters:
obj- the object to check- Returns:
- the order value, or
Ordered.LOWEST_PRECEDENCEas fallback
findOrder
@Nullable protected Integer findOrder(Object obj)
Find an order value indicated by the given object.The default implementation checks against the
Orderedinterface. Can be overridden in subclasses.- Parameters:
obj- the object to check- Returns:
- the order value, or
nullif none found
getPriority
@Nullable public Integer getPriority(Object obj)
Determine a priority value for the given object, if any.The default implementation always returns
null. Subclasses may override this to give specific kinds of values a 'priority' characteristic, in addition to their 'order' semantics. A priority indicates that it may be used for selecting one object over another, in addition to serving for ordering purposes in a list/array.- Parameters:
obj- the object to check- Returns:
- the priority value, or
nullif none - Since:
- 4.1
sort
public static void sort(List<?> list)
Sort the given List with a default OrderComparator.Optimized to skip sorting for lists with size 0 or 1, in order to avoid unnecessary array extraction.
- Parameters:
list- the List to sort- See Also:
List.sort(java.util.Comparator)
sort
public static void sort(Object[] array)
Sort the given array with a default OrderComparator.Optimized to skip sorting for lists with size 0 or 1, in order to avoid unnecessary array extraction.
- Parameters:
array- the array to sort- See Also:
Arrays.sort(Object[], java.util.Comparator)
sortIfNecessary
public static void sortIfNecessary(Object value)
Sort the given array or List with a default OrderComparator, if necessary. Simply skips sorting when given any other value.Optimized to skip sorting for lists with size 0 or 1, in order to avoid unnecessary array extraction.
- Parameters:
value- the array or List to sort- See Also:
Arrays.sort(Object[], java.util.Comparator)