java.lang.Object
- org.forgerock.opendj.ldap.SortKey

```
public final class SortKey
extends Object
```
A search result sort key as defined in RFC 2891 is used to specify how search result entries should be ordered. Sort keys are used with the server side sort request control ServerSideSortRequestControl, but could also be used for performing client side sorting as well.
The following example illustrates how a single sort key may be used to sort entries as they are returned from a search operation using the cn attribute as the sort key:
```
 
 Connection connection = ...;
 SearchRequest request = ...;

 Comparator&lt;Entry> comparator = SortKey.comparator("cn");
 Set<SearchResultEntry>; results = new TreeSet<>(comparator);

 connection.search(request, results);
 
 
```
A sort key includes an attribute description and a boolean value that indicates whether the sort should be ascending or descending. It may also contain a specific ordering matching rule that should be used for the sorting process, although if none is provided it will use the default ordering matching rule for the attribute type.
See Also:

RFC 2891 - LDAP Control Extension for Server Side Sorting of Search Results

Constructor Summary

Constructors
Constructor	Description
`SortKey(String attributeDescription)`	Creates a new sort key using the provided attribute description.
`SortKey(String attributeDescription, boolean isReverseOrder)`	Creates a new sort key using the provided attribute description.
`SortKey(String attributeDescription, boolean isReverseOrder, String orderingMatchingRule)`	Creates a new sort key using the provided attribute description.
`SortKey(AttributeDescription attributeDescription, boolean isReverseOrder, MatchingRule orderingMatchingRule)`	Creates a new sort key using the provided attribute description.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`Comparator<Entry>`	`comparator()`	Returns a `Comparator` which can be used to compare entries using this sort key.
`static Comparator<Entry>`	`comparator(String sortKeys)`	Returns a `Comparator` which can be used to compare entries using the provided string representation of a list of sort keys.
`static Comparator<Entry>`	`comparator(Collection<SortKey> keys)`	Returns a `Comparator` which can be used to compare entries using the provided list of sort keys.
`Comparator<Entry>`	`comparator(Schema schema)`	Returns a `Comparator` which can be used to compare entries using this sort key.
`static Comparator<Entry>`	`comparator(Schema schema, Collection<SortKey> keys)`	Returns a `Comparator` which can be used to compare entries using the provided list of sort keys.
`static Comparator<Entry>`	`comparator(Schema schema, SortKey... keys)`	Returns a `Comparator` which can be used to compare entries using the provided list of sort keys.
`static Comparator<Entry>`	`comparator(SortKey... keys)`	Returns a `Comparator` which can be used to compare entries using the provided list of sort keys.
`boolean`	`equals(Object o)`
`String`	`getAttributeDescription()`	Returns the name of the attribute to be sorted using this sort key.
`String`	`getOrderingMatchingRule()`	Returns the name or OID of the ordering matching rule, if specified, which should be used when comparing attributes using this sort key.
`int`	`hashCode()`
`boolean`	`isReverseOrder()`	Returns `true` if this sort key should be evaluated in reverse (descending) order.
`String`	`toString()`	Returns a string representation of this sort key using the format defined in `valueOf(String)`.
`static SortKey`	`valueOf(String sortKey)`	Parses the provided string representation of a sort key as a `SortKey`.

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - SortKey
```
public SortKey(AttributeDescription attributeDescription,
               boolean isReverseOrder,
               MatchingRule orderingMatchingRule)
```
    Creates a new sort key using the provided attribute description. The returned sort key will compare attributes in the order specified using the named ordering matching rule.
    
    Parameters:
    
    attributeDescription - The name of the attribute to be sorted using this sort key.
    
    isReverseOrder - true if this sort key should be evaluated in reverse (descending) order.
    
    orderingMatchingRule - The name or OID of the ordering matching rule, which should be used when comparing attributes using this sort key, or null if the default ordering matching rule associated with the attribute should be used.
    
    Throws:
    
    NullPointerException - If AttributeDescription was null.
  - SortKey
```
public SortKey(String attributeDescription)
```
    Creates a new sort key using the provided attribute description. The returned sort key will compare attributes in ascending order using the default ordering matching rule associated with the attribute.
    
    Parameters:
    
    attributeDescription - The name of the attribute to be sorted using this sort key.
    
    Throws:
    
    NullPointerException - If AttributeDescription was null.
  - SortKey
```
public SortKey(String attributeDescription,
               boolean isReverseOrder)
```
    Creates a new sort key using the provided attribute description. The returned sort key will compare attributes in the order specified using the default ordering matching rule associated with the attribute.
    
    Parameters:
    
    attributeDescription - The name of the attribute to be sorted using this sort key.
    
    isReverseOrder - true if this sort key should be evaluated in reverse (descending) order.
    
    Throws:
    
    NullPointerException - If AttributeDescription was null.
  - SortKey
```
public SortKey(String attributeDescription,
               boolean isReverseOrder,
               String orderingMatchingRule)
```
    Creates a new sort key using the provided attribute description. The returned sort key will compare attributes in the order specified using the named ordering matching rule.
    
    Parameters:
    
    attributeDescription - The name of the attribute to be sorted using this sort key.
    
    isReverseOrder - true if this sort key should be evaluated in reverse (descending) order.
    
    orderingMatchingRule - The name or OID of the ordering matching rule, which should be used when comparing attributes using this sort key, or null if the default ordering matching rule associated with the attribute should be used.
    
    Throws:
    
    NullPointerException - If AttributeDescription was null.
- Method Detail
  - comparator
```
public static Comparator<Entry> comparator(Collection<SortKey> keys)
                                    throws LdapException
```
    Returns a Comparator which can be used to compare entries using the provided list of sort keys. The sort keys will be decoded using the default schema.
    
    Parameters:
    
    keys - The list of sort keys.
    
    Returns:
    
    The Comparator.
    
    Throws:
    
    LdapException - If one of the sort keys could not be converted to a comparator.
    
    IllegalArgumentException - If keys was empty.
    
    NullPointerException - If keys was null.
  - comparator
```
public static Comparator<Entry> comparator(Schema schema,
                                           Collection<SortKey> keys)
                                    throws LdapException
```
    Returns a Comparator which can be used to compare entries using the provided list of sort keys. The sort keys will be decoded using the provided schema.
    
    Parameters:
    
    schema - The schema which should be used for decoding the sort keys.
    
    keys - The list of sort keys.
    
    Returns:
    
    The Comparator.
    
    Throws:
    
    LdapException - If one of the sort keys could not be converted to a comparator.
    
    IllegalArgumentException - If keys was empty.
    
    NullPointerException - If schema or keys was null.
  - comparator
```
public static Comparator<Entry> comparator(Schema schema,
                                           SortKey... keys)
                                    throws LdapException
```
    Returns a Comparator which can be used to compare entries using the provided list of sort keys. The sort keys will be decoded using the provided schema.
    
    Parameters:
    
    schema - The schema which should be used for decoding the sort keys.
    
    keys - The list of sort keys.
    
    Returns:
    
    The Comparator.
    
    Throws:
    
    LdapException - If one of the sort keys could not be converted to a comparator.
    
    IllegalArgumentException - If keys was empty.
    
    NullPointerException - If schema or keys was null.
  - comparator
```
public static Comparator<Entry> comparator(SortKey... keys)
                                    throws LdapException
```
    Returns a Comparator which can be used to compare entries using the provided list of sort keys. The sort keys will be decoded using the default schema.
    
    Parameters:
    
    keys - The list of sort keys.
    
    Returns:
    
    The Comparator.
    
    Throws:
    
    LdapException - If one of the sort keys could not be converted to a comparator.
    
    IllegalArgumentException - If keys was empty.
    
    NullPointerException - If keys was null.
  - comparator
```
public static Comparator<Entry> comparator(String sortKeys)
                                    throws LdapException
```
    Returns a Comparator which can be used to compare entries using the provided string representation of a list of sort keys. The sort keys will be decoded using the default schema. The string representation is comprised of a comma separate list of sort keys as defined in valueOf(String). There must be at least one sort key present in the string representation.
    
    Parameters:
    
    sortKeys - The list of sort keys.
    
    Returns:
    
    The Comparator.
    
    Throws:
    
    LdapException - If sortKeys is not a valid string representation of a list of sort keys, or if one of the sort keys could not be converted to a comparator.
    
    NullPointerException - If sortKeys was null.
  - valueOf
```
public static SortKey valueOf(String sortKey)
```
    Parses the provided string representation of a sort key as a SortKey. The string representation has the following ABNF (see RFC 4512 for definitions of the elements below):
    SortKey = [ PLUS / HYPHEN ] ; order specifier attributedescription ; attribute description [ COLON oid ] ; ordering matching rule OID
    Examples:
    cn ; case ignore ascending sort on "cn" -cn ; case ignore descending sort on "cn" +cn;lang-fr ; case ignore ascending sort on "cn;lang-fr" -cn;lang-fr:caseExactMatch ; case exact ascending sort on "cn;lang-fr"
    Parameters:
    
    sortKey - The string representation of a sort key.
    
    Returns:
    
    The parsed SortKey.
    
    Throws:
    
    LocalizedIllegalArgumentException - If sortKey is not a valid string representation of a sort key.
    
    NullPointerException - If sortKey was null.
  - comparator
```
public Comparator<Entry> comparator()
                             throws LdapException
```
    Returns a Comparator which can be used to compare entries using this sort key. The attribute description and matching rule, if present, will be decoded using the default schema.
    
    Returns:
    
    The Comparator.
    
    Throws:
    
    LdapException - If attributeDescription is not a valid LDAP string representation of an attribute description, or if no ordering matching rule was found.
  - comparator
```
public Comparator<Entry> comparator(Schema schema)
                             throws LdapException
```
    Returns a Comparator which can be used to compare entries using this sort key. The attribute description and matching rule, if present, will be decoded using the provided schema.
    
    Parameters:
    
    schema - The schema which should be used for decoding the attribute description and matching rule.
    
    Returns:
    
    The Comparator.
    
    Throws:
    
    LdapException - If attributeDescription is not a valid LDAP string representation of an attribute description, or if no ordering matching rule was found.
    
    NullPointerException - If schema was null.
  - getAttributeDescription
```
public String getAttributeDescription()
```
    Returns the name of the attribute to be sorted using this sort key.
    
    Returns:
    
    The name of the attribute to be sorted using this sort key.
  - getOrderingMatchingRule
```
public String getOrderingMatchingRule()
```
    Returns the name or OID of the ordering matching rule, if specified, which should be used when comparing attributes using this sort key.
    
    Returns:
    
    The name or OID of the ordering matching rule, if specified, which should be used when comparing attributes using this sort key, or null if the default ordering matching rule associated with the attribute should be used.
  - isReverseOrder
```
public boolean isReverseOrder()
```
    Returns true if this sort key should be evaluated in reverse (descending) order. More specifically, comparisons performed using the ordering matching rule associated with this sort key will have their results inverted.
    
    Returns:
    
    true if this sort key should be evaluated in reverse (descending) order.
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class Object
  - equals
```
public boolean equals(Object o)
```
    Overrides:
    
    equals in class Object
  - toString
```
public String toString()
```
    Returns a string representation of this sort key using the format defined in valueOf(String).
    
    Overrides:
    
    toString in class Object
    
    Returns:
    
    A string representation of this sort key.

Class SortKey

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

SortKey

SortKey

SortKey

SortKey

Method Detail

comparator

comparator

comparator

comparator

comparator

valueOf

comparator

comparator

getAttributeDescription

getOrderingMatchingRule

isReverseOrder

hashCode

equals

toString