com.pervasive.datarush.tokens.record

Class SortKey

java.lang.Object

com.pervasive.datarush.tokens.record.SortKey

public class SortKey
extends Object

A combination of a key field and an ordering. Used alone or in an ordered collection, specifies the ordering of record data.

See Also:

TokenOrder

Constructor Summary

Constructors

Constructor and Description
SortKey(String name) Create a key using ascending order.
SortKey(String name, TokenOrder order) Create a key using the specified order.

Method Summary

Modifier and Type	Method and Description
static SortKey[]	asc(String... names) Create multiple ascending keys.
static SortKey	asc(String name) Create an ascending key.
static SortKey[]	desc(String... names) Create multiple descending keys.
static SortKey	desc(String name) Create a descending key.
boolean	equals(Object o)
String	getName() Get the field name associated with this key.
static String[]	getNames(SortKey... sortKeys) Extract the field names from several keys.
TokenOrder	getOrder() Get the ordering associated with this key.
static TokenOrder[]	getOrders(SortKey... sortKeys) Extract the orderings from several keys.
int	hashCode()
static SortKey[]	makeSortKeys(TokenOrder order, String... names) Create multiple keys using the specified order.
static SortKey[]	parseKey(String... keyExpressions) Parse key expressions into SortKeys.
String	toString() Pretty-print this SortKey.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

SortKey

public SortKey(String name)

Create a key using ascending order.

Parameters:

name - Name of the key field

SortKey

public SortKey(String name,
               TokenOrder order)

Create a key using the specified order.

Parameters:

name - Name of the key field

order - Order of the data

Method Detail

getName

public String getName()

Get the field name associated with this key.

Returns:

Name of the key field

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

getOrder

public TokenOrder getOrder()

Get the ordering associated with this key.

Returns:

Key's ordering

toString

public String toString()

Pretty-print this SortKey.

Overrides:

toString in class Object

Returns:

String containing field name and associated ordering

asc

public static SortKey asc(String name)

Create an ascending key.

Parameters:

name - Name of the key field

Returns:

Descending sort key

asc

public static SortKey[] asc(String... names)

Create multiple ascending keys.

Parameters:

names - Names of the key fields

Returns:

Ascending sort keys, in the same order as the supplied field names

desc

public static SortKey desc(String name)

Create a descending key.

Parameters:

name - Name of the key field

Returns:

Descending sort key

desc

public static SortKey[] desc(String... names)

Create multiple descending keys.

Parameters:

names - Names of the key fields

Returns:

Descending sort keys, in the same order as the supplied field names

makeSortKeys

public static SortKey[] makeSortKeys(TokenOrder order,
                                     String... names)

Create multiple keys using the specified order.

Parameters:

order - Ordering to use for the keys

names - Names of the key fields

Returns:

Sort keys, in the same order as the supplied field names

getNames

public static String[] getNames(SortKey... sortKeys)

Extract the field names from several keys.

Parameters:

sortKeys - Keys from which to get the field names

Returns:

Field names for the keys, in the same order as the supplied keys

getOrders

public static TokenOrder[] getOrders(SortKey... sortKeys)

Extract the orderings from several keys.

Parameters:

sortKeys - Keys from which to get the orderings

Returns:

Orderings for the keys, in the same order as the supplied keys

parseKey

public static SortKey[] parseKey(String... keyExpressions)

Parse key expressions into SortKeys. A key expression consists of a field name and optionally the sort order: either "asc" or "desc" for ascending and descending respectively. Ascending is the default. Field names with embedded white space characters can optionally use single or double quotes to surround the field name.

Examples:

• "field desc" specifies to sort the column named "field" in descending order.
• "'field with spaces' desc" specifies to sort the column named "field with spaces" in descending order.

Parameters:

keyExpressions - list of expressions to parse into sort keys

Returns:

a list of SortKey instances