org.apache.derby.iapi.types
Interface StringDataValue

All Superinterfaces:

ConcatableDataValue, DataValueDescriptor, java.io.Externalizable, Formatable, Orderable, java.io.Serializable, Storable, TypedFormat, VariableSizeDataValue

All Known Implementing Classes:

CollatorSQLChar, CollatorSQLClob, CollatorSQLLongvarchar, CollatorSQLVarchar, SQLChar, SQLClob, SQLLongvarchar, SQLVarchar

public interface StringDataValue
extends ConcatableDataValue

Field Summary

static int	BOTH
static int	COLLATION_DERIVATION_EXPLICIT
static int	COLLATION_DERIVATION_IMPLICIT
static int	COLLATION_DERIVATION_NONE For a character string type, the collation derivation should always be "explicit"(not possible in Derby 10.3), "implicit" or "none".
static int	COLLATION_TYPE_TERRITORY_BASED
static int	COLLATION_TYPE_UCS_BASIC In Derby 10.3, it is possible to have database with one of the following two configurations 1)all the character columns will have a collation type of UCS_BASIC.
static int	LEADING
static int	TRAILING

Fields inherited from interface org.apache.derby.iapi.types.Orderable

ORDER_OP_EQUALS, ORDER_OP_GREATEROREQUALS, ORDER_OP_GREATERTHAN, ORDER_OP_LESSOREQUALS, ORDER_OP_LESSTHAN

Fields inherited from interface org.apache.derby.iapi.types.VariableSizeDataValue

IGNORE_PRECISION

Method Summary

StringDataValue	ansiTrim(int trimType, StringDataValue trimChar, StringDataValue result) The SQL Ansi trim function.
StringDataValue	concatenate(StringDataValue leftOperand, StringDataValue rightOperand, StringDataValue result) The SQL concatenation '||' operator.
char[]	getCharArray() Get a char array.
StreamHeaderGenerator	getStreamHeaderGenerator() Returns the stream header generator for the string data value.
CharacterStreamDescriptor	getStreamWithDescriptor() Returns a descriptor for the input stream for this data value.
StringDataValue	getValue(java.text.RuleBasedCollator collatorForComparison) Gets either SQLChar/SQLVarchar/SQLLongvarchar/SQLClob(base classes) or CollatorSQLChar/CollatorSQLVarchar/CollatorSQLLongvarch/CollatorSQLClob (subclasses).
BooleanDataValue	like(DataValueDescriptor pattern) The SQL like() function with out escape clause.
BooleanDataValue	like(DataValueDescriptor pattern, DataValueDescriptor escape) The SQL like() function WITH escape clause.
NumberDataValue	locate(StringDataValue searchFrom, NumberDataValue start, NumberDataValue result) Position in searchFrom of the first occurrence of this.value.
StringDataValue	lower(StringDataValue result) Convert the string to lower case.
void	setSoftUpgradeMode(java.lang.Boolean inSoftUpgradeMode) Tells the data value descriptor whether the database is being accessed in soft upgrade mode or not.
void	setValue(java.sql.Clob value) Stuff a StringDataValue with a Clob.
StringDataValue	upper(StringDataValue result) Convert the string to upper case.

Methods inherited from interface org.apache.derby.iapi.types.ConcatableDataValue

charLength, substring

Methods inherited from interface org.apache.derby.iapi.types.DataValueDescriptor

checkHostVariable, coalesce, compare, compare, compare, compare, equals, estimateMemoryUsage, getBoolean, getByte, getBytes, getClone, getDate, getDouble, getFloat, getInt, getLength, getLong, getNewNull, getObject, getShort, getStream, getString, getTime, getTimestamp, getTraceString, getTypeName, greaterOrEquals, greaterThan, in, isNotNull, isNullOp, lessOrEquals, lessThan, normalize, notEquals, readExternalFromArray, recycle, setBigDecimal, setInto, setInto, setObjectForCast, setToNull, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValueFromResultSet, typePrecedence, typeToBigDecimal

Methods inherited from interface org.apache.derby.iapi.services.io.Storable

isNull, restoreToNull

Methods inherited from interface java.io.Externalizable

readExternal, writeExternal

Methods inherited from interface org.apache.derby.iapi.services.io.TypedFormat

getTypeFormatId

Methods inherited from interface org.apache.derby.iapi.types.VariableSizeDataValue

setWidth

Field Detail

BOTH

static final int BOTH

See Also:

Constant Field Values

TRAILING

static final int TRAILING

See Also:

Constant Field Values

LEADING

static final int LEADING

See Also:

Constant Field Values

COLLATION_DERIVATION_NONE

static final int COLLATION_DERIVATION_NONE

For a character string type, the collation derivation should always be "explicit"(not possible in Derby 10.3), "implicit" or "none". We will start by setting it to "implicit" in TypeDescriptorImpl. At runtime, only character string types which are results of aggregate methods dealing with operands with different collation types should have a collation derivation of "none". All the other character string types should have their collation derivation set to "implicit".

See Also:

Constant Field Values

COLLATION_DERIVATION_IMPLICIT

static final int COLLATION_DERIVATION_IMPLICIT

See Also:

COLLATION_DERIVATION_NONE, Constant Field Values

COLLATION_DERIVATION_EXPLICIT

static final int COLLATION_DERIVATION_EXPLICIT

See Also:

COLLATION_DERIVATION_NONE, Constant Field Values

COLLATION_TYPE_UCS_BASIC

static final int COLLATION_TYPE_UCS_BASIC

In Derby 10.3, it is possible to have database with one of the following two configurations 1)all the character columns will have a collation type of UCS_BASIC. This is same as what we do in Derby 10.2 release. 2)all the character string columns belonging to system tables will have collation type of UCS_BASIC but all the character string columns belonging to user tables will have collation type of TERRITORY_BASED. Data types will start with collation type defaulting to UCS_BASIC in TypeDescriptorImpl. This collation type ofcourse makes sense fpr character string types only. It will be ignored for the rest of the types. If a character's collation type should be TERRITORY_BASED, then DTD.setCollationType can be called to change the default of UCS_BASIC.

See Also:

Constant Field Values

COLLATION_TYPE_TERRITORY_BASED

static final int COLLATION_TYPE_TERRITORY_BASED

See Also:

COLLATION_TYPE_UCS_BASIC, Constant Field Values

Method Detail

concatenate

StringDataValue concatenate(StringDataValue leftOperand,
                            StringDataValue rightOperand,
                            StringDataValue result)
                            throws StandardException

The SQL concatenation '||' operator.

Parameters:

leftOperand - String on the left hand side of '||'

rightOperand - String on the right hand side of '||'

result - The result of a previous call to this method, null if not called yet.

Returns:

A ConcatableDataValue containing the result of the '||'

Throws:

StandardException - Thrown on error

like

BooleanDataValue like(DataValueDescriptor pattern)
                      throws StandardException

The SQL like() function with out escape clause.

Parameters:

pattern - the pattern to use

Returns:

A BooleanDataValue containing the result of the like

Throws:

StandardException - Thrown on error

like

BooleanDataValue like(DataValueDescriptor pattern,
                      DataValueDescriptor escape)
                      throws StandardException

The SQL like() function WITH escape clause.

Parameters:

pattern - the pattern to use

escape - the escape character

Returns:

A BooleanDataValue containing the result of the like

Throws:

StandardException - Thrown on error

ansiTrim

StringDataValue ansiTrim(int trimType,
                         StringDataValue trimChar,
                         StringDataValue result)
                         throws StandardException

The SQL Ansi trim function.

Parameters:

trimType - type of trim. Possible values are LEADING, TRAILING or BOTH.

trimChar - The character to trim from this

result - The result of a previous call to this method, null if not called yet.

Returns:

A StringDataValue containing the result of the trim().

Throws:

StandardException

upper

StringDataValue upper(StringDataValue result)
                      throws StandardException

Convert the string to upper case.

Parameters:

result - The result (reusable - allocate if null).

Returns:

The string converted to upper case.

Throws:

StandardException - Thrown on error

lower

StringDataValue lower(StringDataValue result)
                      throws StandardException

Convert the string to lower case.

Parameters:

result - The result (reusable - allocate if null).

Returns:

The string converted to lower case.

Throws:

StandardException - Thrown on error

locate

NumberDataValue locate(StringDataValue searchFrom,
                       NumberDataValue start,
                       NumberDataValue result)
                       throws StandardException

Position in searchFrom of the first occurrence of this.value. The search begins from position start. 0 is returned if searchFrom does not contain this.value. Position 1 is the first character in searchFrom.

Parameters:

searchFrom - - The string to search from

start - - The position to search from in string searchFrom

result - - The object to return

Returns:

The position in searchFrom the fist occurrence of this.value. 0 is returned if searchFrom does not contain this.value.

Throws:

StandardException - Thrown on error

getCharArray

char[] getCharArray()
                    throws StandardException

Get a char array. Typically, this is a simple getter that is cheaper than getString() because we always need to create a char array when doing I/O. Use this instead of getString() where reasonable.

WARNING: may return a character array that has spare characters at the end. MUST be used in conjunction with getLength() to be safe.

Throws:

StandardException - Thrown on error

getValue

StringDataValue getValue(java.text.RuleBasedCollator collatorForComparison)

Gets either SQLChar/SQLVarchar/SQLLongvarchar/SQLClob(base classes) or CollatorSQLChar/CollatorSQLVarchar/CollatorSQLLongvarch/CollatorSQLClob (subclasses). Whether this method returns the base class or the subclass depends on the value of the RuleBasedCollator. If RuleBasedCollator is null, then the object returned would be baseclass otherwise it would be subcalss.

getStreamHeaderGenerator

StreamHeaderGenerator getStreamHeaderGenerator()

Returns the stream header generator for the string data value.

The generator writes the correct header into the destination buffer or stream and also keeps track of whether appending an end-of-stream marker is required or not.

Note that the generator may fail to generate a header if there is no context at the time the header is asked for, and the mode hasn't been set explicitly.

See Also:

setSoftUpgradeMode(java.lang.Boolean)

setSoftUpgradeMode

void setSoftUpgradeMode(java.lang.Boolean inSoftUpgradeMode)

Tells the data value descriptor whether the database is being accessed in soft upgrade mode or not.

Parameters:

inSoftUpgradeMode - true if the database is being accessed in soft upgrade mode, false if not, and null if unknown

getStreamWithDescriptor

CharacterStreamDescriptor getStreamWithDescriptor()
                                                  throws StandardException

Returns a descriptor for the input stream for this data value.

The descriptor contains information about header data, current positions, length, whether the stream should be buffered or not, and if the stream is capable of repositioning itself.

Returns:

A descriptor for the stream, which includes a reference to the stream itself, or null if the value cannot be represented as a stream.

Throws:

StandardException - if obtaining the descriptor fails

setValue

void setValue(java.sql.Clob value)
              throws StandardException

Stuff a StringDataValue with a Clob.

Throws:

StandardException