org.apache.derby.iapi.types
Class BigIntegerDecimal

java.lang.Object
  org.apache.derby.iapi.types.DataType
      org.apache.derby.iapi.types.NumberDataType
          org.apache.derby.iapi.types.BinaryDecimal
              org.apache.derby.iapi.types.BigIntegerDecimal

All Implemented Interfaces:

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

public final class BigIntegerDecimal

extends BinaryDecimal

DECIMAL support using the immutable java.math.BigInteger to perform arithmetic and conversions. Extends BinaryDecimal to use the base support of that class. J2ME/CDC/Foundation includes BigInteger. A BigInteger is used in calculations etc. to represent the integral unscaled value. It is simply created from new BigInteger(data2c). No additional instance fields are used by this class, a possible enhancement would be to keep the BigInteger around but would require calls from the parent class to reset state etc.

See Also:

Serialized Form

Field Summary

protected byte[]	data2c The unscaled value as a binary two's complement array.
private static java.math.BigInteger	MAXLONG_PLUS_ONE
private static java.math.BigInteger	MINLONG_MINUS_ONE
protected int	sqlScale The SQL scale, zero or positive, of the value
private static java.math.BigInteger	TEN

Fields inherited from class org.apache.derby.iapi.types.NumberDataType

ZERO_DECIMAL

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

IGNORE_PRECISION

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

MAX_DECIMAL_PRECISION_SCALE, MIN_DECIMAL_DIVIDE_SCALE

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

Constructor Summary

BigIntegerDecimal()

Method Summary

NumberDataValue	divide(NumberDataValue dividend, NumberDataValue divisor, NumberDataValue result) This method implements the / operator for TINYINT, SMALLINT and INTEGER.
NumberDataValue	divide(NumberDataValue dividend, NumberDataValue divisor, NumberDataValue result, int scale) This method implements the / operator for BigDecimal/BigDecimal
NumberDataValue	divideNN(NumberDataValue left, NumberDataValue right, NumberDataValue result, int scale) Divide two non-null NumberDataValues using DECIMAL arithmetic.
int	estimateMemoryUsage() Estimate the memory usage in bytes of the data value and the overhead of the class.
private BigIntegerDecimal	getBID(DataValueDescriptor value) Obtain a BinaryDecimal that represents the passed in value.
byte	getByte() Return a byte from this value.
DataValueDescriptor	getClone() Clone this DataValueDescriptor.
int	getDecimalValuePrecision() Return the SQL precision of this value.
int	getDecimalValueScale() Return the SQL scale of this value, number of digits after the decimal point, or zero for a whole number.
double	getDouble() Gets the value in the data value descriptor as a double.
float	getFloat() Gets the value in the data value descriptor as a float.
int	getInt() Return a int from this value.
int	getLength() Gets the length of the data value.
long	getLong() Gets the value in the data value descriptor as a long.
DataValueDescriptor	getNewNull() Get a new null value of the same type as this data value.
short	getShort() Return a short from this value.
java.lang.String	getString() Gets the value in the data value descriptor as a String.
int	getTypeFormatId() Return my format identifier.
java.lang.String	getTypeName() Get the SQL name of the datatype
int	hashCode()
protected boolean	isNegative() The isNegative abstract method.
boolean	isNull() see if the decimal value is null.
NumberDataValue	minus(NumberDataValue result) Negate the number.
NumberDataValue	minus(NumberDataValue left, NumberDataValue right, NumberDataValue result) This method implements the - operator for TINYINT, SMALLINT and INTEGER.
NumberDataValue	minusNN(NumberDataValue left, NumberDataValue right, NumberDataValue result) Implement subtraction using addition and negation of the right value.
void	normalize(DataTypeDescriptor desiredType, DataValueDescriptor source) Normalize the source value to this type described by this class and the passed in DataTypeDescriptor.
NumberDataValue	plus(NumberDataValue addend1, NumberDataValue addend2, NumberDataValue result) This method implements the + operator for DECIMAL.
NumberDataValue	plusNN(NumberDataValue left, NumberDataValue right, NumberDataValue result) Add two non-null NumberDataValues using DECIMAL arithmetic.
void	readExternal(java.io.ObjectInput in) Note the use of data2c: we reuse the array if the incoming array is the same length or smaller than the array length.
void	readExternalFromArray(ArrayInputStream in) Read the DataValueDescriptor from the stream.
private static java.math.BigInteger	rescale(java.math.BigInteger bi, int deltaScale) Rescale a BigInteger, a positive delta means the scale is increased, zero no change and negative decrease of scale.
void	restoreToNull() Restore this object to its (SQL)null value.
protected void	setFrom(DataValueDescriptor dvd) Set this DECIMAL value from another DataValueDescriptor
void	setValue(double theValue) Convert from a double, normalize and then convert as a String.
void	setValue(float theValue) Convert from a float, normalize and then convert as a String.
void	setValue(int theValue) Set the value from an int, just copy 'byte-by-byte' from the int to a four byte array.
void	setValue(long theValue) Set the value from a long.
void	setValue(java.lang.Number theValue) Called when setting a DECIMAL value internally or from through a procedure or function.
void	setValue(java.lang.String theValue) Set the value from a String, the format is nnnn Scale always set to zero.
void	setValueFromResultSet(java.sql.ResultSet resultSet, int colNumber, boolean isNullable) Set the value based on the value for the specified DataValueDescriptor from the specified ResultSet.
DataValueDescriptor	setWidth(int desiredPrecision, int desiredScale, boolean errorOnTrunc)
NumberDataValue	times(NumberDataValue left, NumberDataValue right, NumberDataValue result) The SQL * operator.
NumberDataValue	timesNN(NumberDataValue left, NumberDataValue right, NumberDataValue result) Multiple two non-null NumberDataValues using DECIMAL arithmetic.
java.lang.String	toString()
protected int	typeCompare(DataValueDescriptor arg) Compare two non-null NumberDataValues using DECIMAL arithmetic.
int	typePrecedence() Each built-in type in JSQL has a precedence.
int	typeToBigDecimal() DECIMAL implementation.
void	writeExternal(java.io.ObjectOutput out) Distill the Decimal to a byte array and Write out: scale (unsigned byte) length of byte array the byte array

Methods inherited from class org.apache.derby.iapi.types.NumberDataType

absolute, compare, compare, mod, normalizeDOUBLE, normalizeREAL, normalizeREAL, objectNull, setBigDecimal, setValue, setValue, sqrt

Methods inherited from class org.apache.derby.iapi.types.DataType

checkHostVariable, cloneObject, coalesce, dataTypeConversion, equals, equals, flip, genericSetObject, getBoolean, getBytes, getDate, getNationalString, getObject, getStream, getTime, getTimestamp, greaterOrEquals, greaterThan, in, invalidFormat, isNotNull, isNullOp, lessOrEquals, lessThan, notEquals, outOfRange, setInto, setInto, setObjectForCast, setToNull, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, throwLangSetMismatch, throwLangSetMismatch

Methods inherited from class java.lang.Object

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

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

checkHostVariable, coalesce, equals, getBoolean, getBytes, getDate, getObject, getStream, getTime, getTimestamp, greaterOrEquals, greaterThan, in, isNotNull, isNullOp, lessOrEquals, lessThan, notEquals, setInto, setInto, setObjectForCast, setToNull, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue, setValue

Field Detail

TEN

private static final java.math.BigInteger TEN

MAXLONG_PLUS_ONE

private static final java.math.BigInteger MAXLONG_PLUS_ONE

MINLONG_MINUS_ONE

private static final java.math.BigInteger MINLONG_MINUS_ONE

data2c

protected byte[] data2c

The unscaled value as a binary two's complement array.

sqlScale

protected int sqlScale

The SQL scale, zero or positive, of the value

Constructor Detail

BigIntegerDecimal

public BigIntegerDecimal()

Method Detail

getNewNull

public DataValueDescriptor getNewNull()

Description copied from interface: DataValueDescriptor

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

getLong

public long getLong()
             throws StandardException

Description copied from interface: DataValueDescriptor

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

Specified by:

getLong in interface DataValueDescriptor

Overrides:

getLong in class DataType

Returns:

The data value as a long.

Throws:

StandardException - Thrown on error

getFloat

public float getFloat()
               throws StandardException

Description copied from interface: DataValueDescriptor

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

Specified by:

getFloat in interface DataValueDescriptor

Overrides:

getFloat in class DataType

Returns:

The data value as a float.

Throws:

StandardException - Thrown on error

getDouble

public double getDouble()
                 throws StandardException

Description copied from interface: DataValueDescriptor

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

Specified by:

getDouble in interface DataValueDescriptor

Overrides:

getDouble in class DataType

Returns:

The data value as a double.

Throws:

StandardException - Thrown on error

setValue

public void setValue(java.lang.String theValue)
              throws StandardException

Set the value from a String, the format is nnnn Scale always set to zero.

Specified by:

setValue in interface DataValueDescriptor

Overrides:

setValue in class DataType

Parameters:

theValue - The BigDecimal value to set this DataValueDescriptor to

Returns:

This DataValueDescriptor

Throws:

StandardException

getString

public java.lang.String getString()

Description copied from interface: DataValueDescriptor

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.

getDecimalValuePrecision

public int getDecimalValuePrecision()

Return the SQL precision of this value.

Specified by:

getDecimalValuePrecision in interface NumberDataValue

Overrides:

getDecimalValuePrecision in class NumberDataType

typeCompare

protected int typeCompare(DataValueDescriptor arg)
                   throws StandardException

Compare two non-null NumberDataValues using DECIMAL arithmetic.

Specified by:

typeCompare in class NumberDataType

Throws:

StandardException - Thrown on error

plusNN

public NumberDataValue plusNN(NumberDataValue left,
                              NumberDataValue right,
                              NumberDataValue result)
                       throws StandardException

Add two non-null NumberDataValues using DECIMAL arithmetic. Uses add() to perform the calculation.

Specified by:

plusNN in class BinaryDecimal

Throws:

StandardException

minus

public NumberDataValue minus(NumberDataValue result)
                      throws StandardException

Negate the number.

Parameters:

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

Returns:

- operand

Throws:

StandardException - Thrown on error, if result is non-null then its value will be unchanged.

See Also:

NumberDataValue.minus(org.apache.derby.iapi.types.NumberDataValue)

timesNN

public NumberDataValue timesNN(NumberDataValue left,
                               NumberDataValue right,
                               NumberDataValue result)
                        throws StandardException

Multiple two non-null NumberDataValues using DECIMAL arithmetic. Uses BigInteger.multipy() to perform the calculation. Simply multiply the unscaled values and add the scales, proof: left * right = (left_unscaled * 10^-left_scale) * (right_unscaled * 10^-right_scale) = (left_unscaled * 10^-left_scale) * (right_unscaled * 10^-right_scale) = (left_unscaled * right_unscaled) * 10^-(left_scale + right_scale)

Specified by:

timesNN in class BinaryDecimal

Throws:

StandardException

divideNN

public NumberDataValue divideNN(NumberDataValue left,
                                NumberDataValue right,
                                NumberDataValue result,
                                int scale)
                         throws StandardException

Divide two non-null NumberDataValues using DECIMAL arithmetic. Uses divide() to perform the calculation. Simply multiply the unscaled values and subtract the scales, proof: left / right = (left_unscaled * 10^-left_scale) / (right_unscaled * 10^-right_scale) = (left_unscaled / right_unscaled) * (10^-left_scale / 10^-right_scale) = (left_unscaled / right_unscaled) * (10^-(left_scale-right_scale))

Specified by:

divideNN in class BinaryDecimal

Throws:

StandardException

normalize

public void normalize(DataTypeDescriptor desiredType,
                      DataValueDescriptor source)
               throws StandardException

Description copied from interface: DataValueDescriptor

Normalize the source value to this type described by this class and the passed in DataTypeDescriptor. The type of the DataTypeDescriptor must match this class.

Specified by:

normalize in interface DataValueDescriptor

Overrides:

normalize in class DataType

Parameters:

desiredType - The type to normalize the source column to

source - The value to normalize

Throws:

StandardException - Thrown normalization error.

setWidth

public DataValueDescriptor setWidth(int desiredPrecision,
                                    int desiredScale,
                                    boolean errorOnTrunc)
                             throws StandardException

Throws:

StandardException

getBID

private BigIntegerDecimal getBID(DataValueDescriptor value)
                          throws StandardException

Obtain a BinaryDecimal that represents the passed in value.

Throws:

StandardException

rescale

private static java.math.BigInteger rescale(java.math.BigInteger bi,
                                            int deltaScale)

Rescale a BigInteger, a positive delta means the scale is increased, zero no change and negative decrease of scale. It is up to the caller to manage the actual scale of the value, e.g. don't allow the scale to go negative.

Parameters:

bi - value to be rescaled

deltaScale - change of scale

Returns:

rescaled value

toString

public java.lang.String toString()

typeToBigDecimal

public final int typeToBigDecimal()

DECIMAL implementation. Use DECIMAL to indicate to self that another passed in value is an instance of this type.

Specified by:

typeToBigDecimal in interface DataValueDescriptor

Overrides:

typeToBigDecimal in class NumberDataType

typePrecedence

public final int typePrecedence()

Description copied from interface: DataValueDescriptor

Each built-in type in JSQL has a precedence. This precedence determines how to do type promotion when using binary operators. For example, float has a higher precedence than int, so when adding an int to a float, the result type is float. The precedence for some types is arbitrary. For example, it doesn't matter what the precedence of the boolean type is, since it can't be mixed with other types. But the precedence for the number types is critical. The SQL standard requires that exact numeric types be promoted to approximate numeric when one operator uses both. Also, the precedence is arranged so that one will not lose precision when promoting a type.

Specified by:

typePrecedence in interface DataValueDescriptor

Overrides:

typePrecedence in class DataType

Returns:

The precedence of this type.

See Also:

DataValueDescriptor.typePrecedence()

getTypeName

public final java.lang.String getTypeName()

Description copied from interface: DataValueDescriptor

Get the SQL name of the datatype

Specified by:

getTypeName in interface DataValueDescriptor

Returns:

The SQL name of the datatype

getTypeFormatId

public final int getTypeFormatId()

Return my format identifier.

Specified by:

getTypeFormatId in interface TypedFormat

Returns:

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

See Also:

TypedFormat.getTypeFormatId()

isNull

public boolean isNull()

see if the decimal value is null.

Specified by:

isNull in interface Storable

Returns:

true if the value is null and false otherwise.

restoreToNull

public void restoreToNull()

Description copied from interface: Storable

Restore this object to its (SQL)null value.

Specified by:

restoreToNull in interface Storable

isNegative

protected boolean isNegative()

Description copied from class: NumberDataType

The isNegative abstract method. Checks to see if this.value is negative. To be implemented by each NumberDataType.

Specified by:

isNegative in class NumberDataType

Returns:

A boolean. If this.value is negative, return true. For positive values or null, return false.

setValue

public void setValue(long theValue)

Set the value from a long.

Specified by:

setValue in interface DataValueDescriptor

Overrides:

setValue in class DataType

Parameters:

theValue - The value to set this DataValueDescriptor to

Returns:

This DataValueDescriptor

setValue

public final void setValue(int theValue)

Set the value from an int, just copy 'byte-by-byte' from the int to a four byte array. Then reduce.

Specified by:

setValue in interface DataValueDescriptor

Overrides:

setValue in class DataType

Parameters:

theValue - The value to set this DataValueDescriptor to

Returns:

This DataValueDescriptor

See Also:

NumberDataValue.setValue(java.lang.Number)

setValue

public final void setValue(double theValue)
                    throws StandardException

Convert from a double, normalize and then convert as a String.

Specified by:

setValue in interface DataValueDescriptor

Overrides:

setValue in class DataType

Parameters:

theValue - The value to set this DataValueDescriptor to

Returns:

This DataValueDescriptor

Throws:

StandardException - Thrown on error

setValue

public final void setValue(float theValue)
                    throws StandardException

Convert from a float, normalize and then convert as a String.

Specified by:

setValue in interface DataValueDescriptor

Overrides:

setValue in class DataType

Parameters:

theValue - The value to set this DataValueDescriptor to

Returns:

This DataValueDescriptor

Throws:

StandardException - Thrown on error

setValue

public void setValue(java.lang.Number theValue)
              throws StandardException

Called when setting a DECIMAL value internally or from through a procedure or function. Handles long in addition to BigDecimal to handle identity being stored as a long but returned as a DECIMAL.

Specified by:

setValue in interface NumberDataValue

Overrides:

setValue in class NumberDataType

Throws:

StandardException - Thrown on error

See Also:

NumberDataValue.setValue(java.lang.Number)

setFrom

protected void setFrom(DataValueDescriptor dvd)
                throws StandardException

Set this DECIMAL value from another DataValueDescriptor

Overrides:

setFrom in class DataType

Throws:

StandardException

getInt

public final int getInt()
                 throws StandardException

Return a int from this value.

Specified by:

getInt in interface DataValueDescriptor

Overrides:

getInt in class DataType

Returns:

The data value as a int.

Throws:

StandardException - this value is out of range for an int

getByte

public final byte getByte()
                   throws StandardException

Return a byte from this value.

Specified by:

getByte in interface DataValueDescriptor

Overrides:

getByte in class DataType

Returns:

The data value as a byte.

Throws:

StandardException - this value is out of range for a short

getShort

public final short getShort()
                     throws StandardException

Return a short from this value.

Specified by:

getShort in interface DataValueDescriptor

Overrides:

getShort in class DataType

Returns:

The data value as a short.

Throws:

StandardException - this value is out of range for a short

plus

public final NumberDataValue plus(NumberDataValue addend1,
                                  NumberDataValue addend2,
                                  NumberDataValue result)
                           throws StandardException

This method implements the + operator for DECIMAL.

Specified by:

plus in interface NumberDataValue

Overrides:

plus in class NumberDataType

Parameters:

addend1 - One of the addends

addend2 - The other addend

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

Returns:

A SQLDecimal containing the result of the addition

Throws:

StandardException - Thrown on error

times

public final NumberDataValue times(NumberDataValue left,
                                   NumberDataValue right,
                                   NumberDataValue result)
                            throws StandardException

Description copied from interface: NumberDataValue

The SQL * operator.

Specified by:

times in interface NumberDataValue

Parameters:

left - The left operand

right - The right operand

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

Returns:

left * right

Throws:

StandardException - Thrown on error, if result is non-null then its value will be unchanged.

divide

public NumberDataValue divide(NumberDataValue dividend,
                              NumberDataValue divisor,
                              NumberDataValue result)
                       throws StandardException

Description copied from class: NumberDataType

This method implements the / operator for TINYINT, SMALLINT and INTEGER. Specialized methods are not required for TINYINT and SMALLINT as the Java virtual machine always executes byte and int division as integer.

Specified by:

divide in interface NumberDataValue

Overrides:

divide in class NumberDataType

Parameters:

dividend - The numerator

divisor - The denominator

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

Returns:

A SQLInteger containing the result of the division

Throws:

StandardException - Thrown on error

divide

public final NumberDataValue divide(NumberDataValue dividend,
                                    NumberDataValue divisor,
                                    NumberDataValue result,
                                    int scale)
                             throws StandardException

This method implements the / operator for BigDecimal/BigDecimal

Specified by:

divide in interface NumberDataValue

Overrides:

divide in class NumberDataType

Parameters:

dividend - The numerator

divisor - The denominator

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

scale - The result scale, if < 0, calculate the scale according to the actual values' sizes

Returns:

A SQLDecimal containing the result of the division

Throws:

StandardException - Thrown on error

minus

public final NumberDataValue minus(NumberDataValue left,
                                   NumberDataValue right,
                                   NumberDataValue result)
                            throws StandardException

Description copied from class: NumberDataType

This method implements the - operator for TINYINT, SMALLINT and INTEGER.

Specified by:

minus in interface NumberDataValue

Overrides:

minus in class NumberDataType

Parameters:

left - The value to be subtracted from

right - The value to be subtracted

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

Returns:

A SQLInteger containing the result of the subtraction

Throws:

StandardException - Thrown on error

minusNN

public NumberDataValue minusNN(NumberDataValue left,
                               NumberDataValue right,
                               NumberDataValue result)
                        throws StandardException

Implement subtraction using addition and negation of the right value.

Throws:

StandardException

getDecimalValueScale

public int getDecimalValueScale()

Return the SQL scale of this value, number of digits after the decimal point, or zero for a whole number.

Specified by:

getDecimalValueScale in interface NumberDataValue

Overrides:

getDecimalValueScale in class NumberDataType

writeExternal

public void writeExternal(java.io.ObjectOutput out)
                   throws java.io.IOException

Distill the Decimal to a byte array and Write out:

• scale (unsigned byte)
• length of byte array
• the byte array

Specified by:

writeExternal in interface java.io.Externalizable

Throws:

java.io.IOException

readExternal

public void readExternal(java.io.ObjectInput in)
                  throws java.io.IOException

Note the use of data2c: we reuse the array if the incoming array is the same length or smaller than the array length.

Specified by:

readExternal in interface java.io.Externalizable

Throws:

java.io.IOException

See Also:

Externalizable.readExternal(java.io.ObjectInput)

readExternalFromArray

public void readExternalFromArray(ArrayInputStream in)
                           throws java.io.IOException

Description copied from interface: DataValueDescriptor

Read the DataValueDescriptor from the stream.

Initialize the data value by reading it's values from the ArrayInputStream. This interface is provided as a way to achieve possible performance enhancement when reading an array can be optimized over reading from a generic stream from readExternal().

Specified by:

readExternalFromArray in interface DataValueDescriptor

Parameters:

in - The array stream positioned at the beginning of the byte stream to read from.

Throws:

java.io.IOException - Usual error is if you try to read past limit on the stream.

getLength

public final int getLength()

Description copied from interface: DataValueDescriptor

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.

Specified by:

getLength in interface DataValueDescriptor

Returns:

The length of the data value

getClone

public DataValueDescriptor getClone()

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.

Specified by:

getClone in interface DataValueDescriptor

Returns:

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

setValueFromResultSet

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

Description copied from interface: DataValueDescriptor

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

Specified by:

setValueFromResultSet in interface DataValueDescriptor

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)

Returns:

Nothing.

Throws:

StandardException - Thrown on error

java.sql.SQLException - Error accessing the result set

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.

Specified by:

estimateMemoryUsage in interface DataValueDescriptor

Returns:

the estimated memory usage

hashCode

public int hashCode()