Class StorableFormatId

java.lang.Object

org.apache.derby.iapi.types.DataType

org.apache.derby.impl.store.access.StorableFormatId

All Implemented Interfaces:

Externalizable, Serializable, Comparable, Formatable, Storable, TypedFormat, DataValueDescriptor, Orderable

public class StorableFormatId
extends DataType

See Also:

• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
private static final int	BASE_MEMORY_USAGE
private int	format_id

Fields inherited from interface DataValueDescriptor

UNKNOWN_LOGICAL_LENGTH

Fields inherited from interface Orderable

ORDER_OP_EQUALS, ORDER_OP_GREATEROREQUALS, ORDER_OP_GREATERTHAN, ORDER_OP_LESSOREQUALS, ORDER_OP_LESSTHAN

Constructor Summary

Constructors

Constructor	Description
StorableFormatId()
StorableFormatId(int value)

Method Summary

Modifier and Type	Method	Description
DataValueDescriptor	cloneValue(boolean forceMaterialization)	Clone this DataValueDescriptor.
int	compare(DataValueDescriptor other)	Compare this Orderable with a given Orderable for the purpose of index positioning.
int	estimateMemoryUsage()	Estimate the memory usage in bytes of the data value and the overhead of the class.
int	getLength()	Gets the length of the data value.
DataValueDescriptor	getNewNull()	Get a new null value of the same type as this data value.
Object	getObject()	Gets the value in the data value descriptor as a Java Object.
String	getString()	Gets the value in the data value descriptor as a String.
int	getTypeFormatId()	Return my format identifier.
String	getTypeName()	Get the SQL name of the datatype
int	getValue()
boolean	isNull()	Return whether the value is null or not.
void	readExternal(ObjectInput in)
void	restoreToNull()	Restore this object to its (SQL)null value.
protected void	setFrom(DataValueDescriptor theValue)	Set the value of this DataValueDescriptor from another.
void	setValue(int input_value)	Set the value of this DataValueDescriptor to the given int value At DataType level just throws an error lower classes will override
void	setValueFromResultSet(ResultSet resultSet, int colNumber, boolean isNullable)	Set the value based on the value for the specified DataValueDescriptor from the specified ResultSet.
void	writeExternal(ObjectOutput out)

Methods inherited from class DataType

checkHostVariable, cloneHolder, coalesce, compare, compare, compare, compareTo, dataTypeConversion, equals, equals, flip, getBoolean, getByte, getBytes, getDate, getDouble, getFloat, getInt, getLong, getShort, getStream, getTime, getTimestamp, getTraceString, greaterOrEquals, greaterThan, hasStream, in, invalidFormat, isNotNull, isNullOp, lessOrEquals, lessThan, normalize, notEquals, outOfRange, readExternalFromArray, recycle, setBigDecimal, setInto, setInto, setObjectForCast, setToNull, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, throwLangSetMismatch, typePrecedence, typeToBigDecimal

Methods inherited from class Object

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

Field Details

format_id

private int format_id

BASE_MEMORY_USAGE

private static final int BASE_MEMORY_USAGE

Constructor Details

StorableFormatId

public StorableFormatId()

StorableFormatId

public StorableFormatId(int value)

Method Details

estimateMemoryUsage

public int estimateMemoryUsage()

Description copied from interface: DataValueDescriptor

Estimate the memory usage in bytes of the data value and the overhead of the class.

Returns:

the estimated memory usage

getValue

public int getValue()

setValue

public void setValue(int input_value)

Description copied from class: DataType

Set the value of this DataValueDescriptor to the given int value At DataType level just throws an error lower classes will override

Specified by:

setValue in interface DataValueDescriptor

Overrides:

setValue in class DataType

Parameters:

input_value - The value to set this DataValueDescriptor to

getTypeFormatId

public int getTypeFormatId()

Return my format identifier.

Returns:

The identifier. (A UUID stuffed in an array of 16 bytes).

See Also:

• TypedFormat.getTypeFormatId()

isNull

public boolean isNull()

Description copied from interface: Storable

Return whether the value is null or not.

Returns:

true if the value is null and false otherwise.

writeExternal

public void writeExternal(ObjectOutput out)
                   throws IOException

Throws:

IOException

readExternal

public void readExternal(ObjectInput in)
                  throws IOException

Throws:

IOException

See Also:

• Externalizable.readExternal(ObjectInput)

restoreToNull

public void restoreToNull()

Description copied from interface: Storable

Restore this object to its (SQL)null value.

getLength

public int getLength()
              throws StandardException

Gets the length of the data value. The meaning of this is implementation-dependent. For string types, it is the number of characters in the string. For numeric types, it is the number of bytes used to store the number. This is the actual length of this value, not the length of the type it was defined as. For example, a VARCHAR value may be shorter than the declared VARCHAR (maximum) length.

Returns:

The length of the data value

Throws:

StandardException - On error

See Also:

• DataValueDescriptor.getLength()

getString

public String getString()
                 throws StandardException

Gets the value in the data value descriptor as a String. Throws an exception if the data value is not a string.

Returns:

The data value as a String.

Throws:

StandardException - Thrown on error

See Also:

• DataValueDescriptor.getString()

getObject

public Object getObject()
                 throws StandardException

Gets the value in the data value descriptor as a Java Object. The type of the Object will be the Java object type corresponding to the data value's SQL type. JDBC defines a mapping between Java object types and SQL types - we will allow that to be extended through user type definitions. Throws an exception if the data value is not an object (yeah, right).

Specified by:

getObject in interface DataValueDescriptor

Overrides:

getObject in class DataType

Returns:

The data value as an Object.

Throws:

StandardException - Thrown on error

See Also:

• DataValueDescriptor.getObject()

cloneValue

public DataValueDescriptor cloneValue(boolean forceMaterialization)

Description copied from interface: DataValueDescriptor

Clone this DataValueDescriptor. Results in a new object that has the same value as this but can be modified independently.

Even though the objects can be modified independently regardless of the value of forceMaterialization, both the clone and the original may be dependent on the store state if forceMaterialization is set to false. An example is if you need to access the value you just read using cloneValue after the current transaction has ended, or after the source result set has been closed.

Parameters:

forceMaterialization - any streams representing the data value will be materialized if true, the data value will be kept as a stream if possible if false

Returns:

A clone of the DataValueDescriptor with the same initial value as this.

See Also:

• DataValueDescriptor.cloneValue(boolean)

getNewNull

public DataValueDescriptor getNewNull()

Get a new null value of the same type as this data value.

See Also:

• DataValueDescriptor.getNewNull()

setValueFromResultSet

public void setValueFromResultSet(ResultSet resultSet,
 int colNumber,
 boolean isNullable)
                           throws StandardException,
SQLException

Set the value based on the value for the specified DataValueDescriptor from the specified ResultSet.

Parameters:

resultSet - The specified ResultSet.

colNumber - The 1-based column # into the resultSet.

isNullable - Whether or not the column is nullable (No need to call wasNull() if not)

Throws:

StandardException - Thrown on error

SQLException - Error accessing the result set

See Also:

• DataValueDescriptor.setValueFromResultSet(ResultSet, int, boolean)

setFrom

protected void setFrom(DataValueDescriptor theValue)
                throws StandardException

Set the value of this DataValueDescriptor from another.

Overrides:

setFrom in class DataType

Parameters:

theValue - The Date value to set this DataValueDescriptor to

Throws:

StandardException

See Also:

• DataValueDescriptor.setValue(int)

getTypeName

public String getTypeName()

Get the SQL name of the datatype

Returns:

The SQL name of the datatype

See Also:

• DataValueDescriptor.getTypeName()

compare

public int compare(DataValueDescriptor other)
            throws StandardException

Compare this Orderable with a given Orderable for the purpose of index positioning. This method treats nulls as ordered values - that is, it treats SQL null as equal to null and less than all other values.

Parameters:

other - The Orderable to compare this one to.

Returns:

<0 - this Orderable is less than other. 0 - this Orderable equals other. >0 - this Orderable is greater than other. The code should not explicitly look for -1, or 1.

Throws:

StandardException - Thrown on error

See Also:

• DataValueDescriptor.compare(DataValueDescriptor)