org.apache.derby.iapi.types
Class WorkHorseForCollatorDatatypes

java.lang.Object
  org.apache.derby.iapi.types.WorkHorseForCollatorDatatypes

final class WorkHorseForCollatorDatatypes
extends java.lang.Object

WorkHorseForCollatorDatatypes class holds on to RuleBasedCollator, and the base SQLChar object for the collation sensitive SQLChar, SQLVarchar, SQLLongvarchar and SQLClob. This class uses RuleBasedCollator and SQLChar object in the collation sensitive methods to do the comparison. The reason for encapsulating this here is that the collation version of SQLChar, SQLVarchar, SQLLongvarchar and SQLClob do not all have to duplicate the code for collation sensitive methods. Instead, they can simply delegate the work to methods defined in this class.

Field Summary

private java.text.RuleBasedCollator	collatorForCharacterDatatypes Use this object for collation on character datatype.
private SQLChar	stringData collatorForCharacterDatatypes will be used on this SQLChar to determine collationElementsForString.

Constructor Summary

WorkHorseForCollatorDatatypes(java.text.RuleBasedCollator collatorForCharacterDatatypes, SQLChar stringData)

Method Summary

(package private) java.text.RuleBasedCollator	getCollatorForCollation() Get the RuleBasedCollator which is getting used for collation sensitive methods.
(package private) boolean	hasSingleCollationElement() Check if the string consists of a single collation element.
(package private) BooleanDataValue	like(DataValueDescriptor pattern) This method implements the like function for char (with no escape value).
(package private) BooleanDataValue	like(DataValueDescriptor pattern, DataValueDescriptor escape) This method implements the like function for char with an escape value.
(package private) int	stringCompare(SQLChar str1, SQLChar str2)

Methods inherited from class java.lang.Object

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

Field Detail

collatorForCharacterDatatypes

private java.text.RuleBasedCollator collatorForCharacterDatatypes

Use this object for collation on character datatype. This collator object is passed as a parameter to the constructor.

stringData

private SQLChar stringData

collatorForCharacterDatatypes will be used on this SQLChar to determine collationElementsForString. The collationElementsForString is used by the like method to do Collator specific comparison. This SQLChar object is passed as a parameter to the constructor.

Constructor Detail

WorkHorseForCollatorDatatypes

WorkHorseForCollatorDatatypes(java.text.RuleBasedCollator collatorForCharacterDatatypes,
                              SQLChar stringData)

Method Detail

stringCompare

int stringCompare(SQLChar str1,
                  SQLChar str2)
            throws StandardException

Throws:

StandardException

See Also:

SQLChar.stringCompare(SQLChar, SQLChar)

like

BooleanDataValue like(DataValueDescriptor pattern)
                throws StandardException

This method implements the like function for char (with no escape value). The difference in this method and the same method in SQLChar is that here we use special Collator object to do the comparison rather than using the Collator object associated with the default jvm locale.

Parameters:

pattern - The pattern to use

Returns:

A SQL boolean value telling whether the first operand is like the second operand

Throws:

StandardException - Thrown on error

like

BooleanDataValue like(DataValueDescriptor pattern,
                      DataValueDescriptor escape)
                throws StandardException

This method implements the like function for char with an escape value.

Parameters:

pattern - The pattern to use

Returns:

A SQL boolean value telling whether the first operand is like the second operand

Throws:

StandardException - Thrown on error

getCollatorForCollation

java.text.RuleBasedCollator getCollatorForCollation()

Get the RuleBasedCollator which is getting used for collation sensitive methods.

hasSingleCollationElement

boolean hasSingleCollationElement()
                            throws StandardException

Check if the string consists of a single collation element.

Returns:

true iff it's a single collation element

Throws:

StandardException

See Also:

CollationElementsInterface.hasSingleCollationElement()