uk.ac.starlink.feather

Class VariableStarColumnWriter

java.lang.Object

uk.ac.starlink.feather.StarColumnWriter

uk.ac.starlink.feather.VariableStarColumnWriter

All Implemented Interfaces:

uk.ac.bristol.star.feather.FeatherColumnWriter

public abstract class VariableStarColumnWriter
extends StarColumnWriter

StarColumnWriter implementations for variable-length values.

Since:

27 Feb 2020

Author:

Mark Taylor

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	VariableStarColumnWriter.PointerSize Enumeration for pointer size.

Nested classes/interfaces inherited from class uk.ac.starlink.feather.StarColumnWriter

StarColumnWriter.DataStat

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	VariableStarColumnWriter(StarTable table, int icol, uk.ac.bristol.star.feather.FeatherType ftype, boolean isNullable, VariableStarColumnWriter.PointerSize psize) Constructor.

Method Summary

Modifier and Type	Method and Description
static VariableStarColumnWriter	createByteArrayWriter(StarTable table, int icol, boolean isNullable, VariableStarColumnWriter.PointerSize psize) Returns a column writer for variable-length byte array values.
ItemAccumulator	createItemAccumulator(StoragePolicy storage)
static VariableStarColumnWriter	createStringWriter(StarTable table, int icol, boolean isNullable, VariableStarColumnWriter.PointerSize psize) Returns a column writer for variable-length string values.
abstract int	getItemSize(Object item) Returns the number of bytes that a given item will occupy in the output stream.
StarColumnWriter.DataStat	writeDataBytes(OutputStream out) Writes the bytes consituting the data stream for this column, excluding any optional validity mask.
abstract int	writeItemBytes(OutputStream out, Object item) Writes a value to the output stream.

Methods inherited from class uk.ac.starlink.feather.StarColumnWriter

getColumnIndex, getFeatherType, getName, getTable, getUserMetadata, isNullable, writeColumnBytes

Methods inherited from class java.lang.Object

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

Constructor Detail

VariableStarColumnWriter

protected VariableStarColumnWriter(StarTable table,
                                   int icol,
                                   uk.ac.bristol.star.feather.FeatherType ftype,
                                   boolean isNullable,
                                   VariableStarColumnWriter.PointerSize psize)

Constructor.

Parameters:

table - input table

icol - column index

ftype - output data type

isNullable - if true, nulls will be marked as invalid; if false, they will just be represented as zero length

psize - pointer size

Method Detail

getItemSize

public abstract int getItemSize(Object item)

Returns the number of bytes that a given item will occupy in the output stream.

Parameters:

item - writable value

Returns:

byte count

writeItemBytes

public abstract int writeItemBytes(OutputStream out,
                                   Object item)
                            throws IOException

Writes a value to the output stream. The output value must be consistent with getItemSize(java.lang.Object).

Parameters:

out - destination stream

item - writable value

Returns:

number of bytes written

Throws:

IOException

writeDataBytes

public StarColumnWriter.DataStat writeDataBytes(OutputStream out)
                                         throws IOException

Description copied from class: StarColumnWriter

Writes the bytes consituting the data stream for this column, excluding any optional validity mask. Note the output does not need to be aligned on an 8-byte boundary.

Specified by:

writeDataBytes in class StarColumnWriter

Parameters:

out - destination stream

Returns:

information about what was actually written

Throws:

IOException

createItemAccumulator

public ItemAccumulator createItemAccumulator(StoragePolicy storage)

Specified by:

createItemAccumulator in class StarColumnWriter

createStringWriter

public static VariableStarColumnWriter createStringWriter(StarTable table,
                                                          int icol,
                                                          boolean isNullable,
                                                          VariableStarColumnWriter.PointerSize psize)

Returns a column writer for variable-length string values.

Parameters:

table - input table

icol - column index

isNullable - if true, nulls will be marked as invalid; if false, they will just be represented as zero length strings

psize - pointer size

createByteArrayWriter

public static VariableStarColumnWriter createByteArrayWriter(StarTable table,
                                                             int icol,
                                                             boolean isNullable,
                                                             VariableStarColumnWriter.PointerSize psize)

Returns a column writer for variable-length byte array values.

Parameters:

table - input table

icol - column index

isNullable - if true, nulls will be marked as invalid; if false, they will just be represented as zero length arrays

psize - pointer size