Package org.apache.druid.frame.field

Class StringFieldWriter

java.lang.Object

org.apache.druid.frame.field.StringFieldWriter

All Implemented Interfaces:

Closeable, AutoCloseable, FieldWriter

public class StringFieldWriter
extends Object
implements FieldWriter

Wraps a DimensionSelector and writes to rframe rows. See StringFieldReader for format details.

Field Summary

Fields

Modifier and Type	Field	Description
static final byte	NOT_NULL_BYTE
static final byte	NULL_BYTE	Different from the values in TypeStrategies, since we want to be able to sort as bytes, and we want nulls to come before non-nulls.
static final byte	NULL_ROW	Null rows are represented by NULL_ROW.
static final byte	ROW_TERMINATOR
static final byte	VALUE_TERMINATOR

Constructor Summary

Constructors

Constructor	Description
StringFieldWriter(DimensionSelector selector, boolean removeNullbytes)

Method Summary

Modifier and Type	Method	Description
void	close()	Releases resources held by this writer.
long	writeTo(org.apache.datasketches.memory.WritableMemory memory, long position, long maxSize)	Writes the current selection at the given memory position.

Methods inherited from class java.lang.Object

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

Field Details

VALUE_TERMINATOR

public static final byte VALUE_TERMINATOR

See Also:

• Constant Field Values

ROW_TERMINATOR

public static final byte ROW_TERMINATOR

See Also:

• Constant Field Values

NULL_ROW

public static final byte NULL_ROW

Null rows are represented by NULL_ROW. Same byte value as VALUE_TERMINATOR, but not ambiguous: NULL_ROW can only occur as the first byte in a row, and VALUE_TERMINATOR can never occur as the first byte in a row.

See Also:

• Constant Field Values

NULL_BYTE

public static final byte NULL_BYTE

Different from the values in TypeStrategies, since we want to be able to sort as bytes, and we want nulls to come before non-nulls.

See Also:

• Constant Field Values

NOT_NULL_BYTE

public static final byte NOT_NULL_BYTE

See Also:

• Constant Field Values

Constructor Details

StringFieldWriter

public StringFieldWriter(DimensionSelector selector,
 boolean removeNullbytes)

Method Details

writeTo

public long writeTo(org.apache.datasketches.memory.WritableMemory memory,
 long position,
 long maxSize)

Description copied from interface: FieldWriter

Writes the current selection at the given memory position.

Specified by:

writeTo in interface FieldWriter

Parameters:

memory - memory region in little-endian order

position - position to write

maxSize - maximum number of bytes to write

Returns:

number of bytes written, or -1 if "maxSize" was not enough memory

close

public void close()

Description copied from interface: FieldWriter

Releases resources held by this writer.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Specified by:

close in interface FieldWriter