Package com.rapidminer.belt.buffer

Class UInt4NominalBuffer

java.lang.Object

com.rapidminer.belt.buffer.NominalBuffer

com.rapidminer.belt.buffer.UInt4NominalBuffer

public class UInt4NominalBuffer
extends NominalBuffer

Implementation of a NominalBuffer with category index format IntegerFormats.Format.UNSIGNED_INT4 that can hold 15 different categories. Two category indices are stored in a single byte.

Author:

Gisa Meier

Field Summary

Fields inherited from class com.rapidminer.belt.buffer.NominalBuffer

type

Method Summary

Modifier and Type	Method	Description
int	differentValues()	Returns the number of different values that were fed into this buffer.
java.lang.String	get(int index)	Retrieves the value at the given index.
IntegerFormats.Format	indexFormat()
void	set(int index, java.lang.String value)	Sets the data at the given index to the given value.
boolean	setSave(int index, java.lang.String value)	Tries to set the data at the given index to the given value.
int	size()
CategoricalColumn	toBooleanColumn(java.lang.String positiveValue)	Creates a boolean column with the given positive value if the dictionary has at most two values.
CategoricalColumn	toColumn()	Returns a column of the given type using the buffer's data.

Methods inherited from class com.rapidminer.belt.buffer.NominalBuffer

toString

Methods inherited from class java.lang.Object

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

Method Detail

get

public java.lang.String get(int index)

Description copied from class: NominalBuffer

Retrieves the value at the given index. This method is thread-safe and can be used alongside invocations of NominalBuffer.set(int, java.lang.String) and NominalBuffer.setSave(int, java.lang.String). However, this method might not return the latest value set on another thread.

Specified by:

get in class NominalBuffer

Parameters:

index - the index to look up

Returns:

the value at the index

set

public void set(int index,
                java.lang.String value)

Sets the data at the given index to the given value.

Due to the compressed integer format, this method is only thread-safe for indices with different results when divided by 2. Values can be lost when writing at indices index1 and index2 with index1/2 == index2/2 from different threads. So when writing in batches of indices [m,n) you must ensure that m and n are even.

Specified by:

set in class NominalBuffer

Parameters:

index - the index where the value should be set

value - the value to set

setSave

public boolean setSave(int index,
                       java.lang.String value)

Tries to set the data at the given index to the given value. Returns true if it worked and false if the buffer format cannot hold any more different values.

Due to the compressed integer format, this method is only thread-safe for indices with different results when divided by 2. Values can be lost when writing at indices index1 and index2 with index1/2 == index2/2 from different threads. So when writing in batches of indices [m,n) you must ensure that m and n are even.

Specified by:

setSave in class NominalBuffer

Parameters:

index - the index where the value should be set

value - the value to set

Returns:

false if the buffer contained already to many different values to take this value, true otherwise

size

public int size()

Specified by:

size in class NominalBuffer

Returns:

the size of the buffer

indexFormat

public IntegerFormats.Format indexFormat()

Specified by:

indexFormat in class NominalBuffer

Returns:

the category index format of the buffer determining the maximal number of categories

differentValues

public int differentValues()

Description copied from class: NominalBuffer

Returns the number of different values that were fed into this buffer. null values are not counted.

Specified by:

differentValues in class NominalBuffer

Returns:

the number of different values

toColumn

public CategoricalColumn toColumn()

Description copied from class: NominalBuffer

Returns a column of the given type using the buffer's data. The buffer becomes read-only. In contrast to constructing a new buffer from a column this method does not copy the data.

Specified by:

toColumn in class NominalBuffer

Returns:

the categorical column

toBooleanColumn

public CategoricalColumn toBooleanColumn(java.lang.String positiveValue)

Description copied from class: NominalBuffer

Creates a boolean column with the given positive value if the dictionary has at most two values. The positive value must be either one of the dictionary values, making the other value, if it exists, negative. Or in case of a dictionary with only one value the positive value can be null making the only value negative.

Specified by:

toBooleanColumn in class NominalBuffer

Parameters:

positiveValue - the positive value or null

Returns:

a categorical column with a boolean Dictionary