Package org.apache.druid.segment.data

Class EncodedStringDictionaryWriter

java.lang.Object

org.apache.druid.segment.data.EncodedStringDictionaryWriter

All Implemented Interfaces:

DictionaryWriter<String>, Serializer

public class EncodedStringDictionaryWriter
extends Object
implements DictionaryWriter<String>

Field Summary

Fields

Modifier and Type	Field	Description
static byte	VERSION

Constructor Summary

Constructors

Constructor	Description
EncodedStringDictionaryWriter(DictionaryWriter<byte[]> delegate, StringEncodingStrategy encodingStrategy)

Method Summary

Modifier and Type	Method	Description
String	get(int dictId)	Returns an object that has already been written via the DictionaryWriter.write(T) method.
int	getCardinality()	Returns the number of items that have been written so far in this dictionary.
long	getSerializedSize()	Returns the number of bytes, that this Serializer will write to the output _channel_ (not smoosher) on a Serializer.writeTo(java.nio.channels.WritableByteChannel, org.apache.druid.java.util.common.io.smoosh.FileSmoosher) call.
boolean	isSorted()
void	open()	Prepares the writer for writing
int	write(String objectToWrite)	Writes an object to the dictionary.
void	writeTo(WritableByteChannel channel, FileSmoosher smoosher)	Writes the serialized form of this object.

Methods inherited from class java.lang.Object

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

Field Detail

VERSION

public static final byte VERSION

See Also:

Constant Field Values

Constructor Detail

EncodedStringDictionaryWriter

public EncodedStringDictionaryWriter(DictionaryWriter<byte[]> delegate,
                                     StringEncodingStrategy encodingStrategy)

Method Detail

isSorted

public boolean isSorted()

Specified by:

isSorted in interface DictionaryWriter<String>

open

public void open()
          throws IOException

Description copied from interface: DictionaryWriter

Prepares the writer for writing

Specified by:

open in interface DictionaryWriter<String>

Throws:

IOException - if there is a problem with IO

write

public int write(@Nullable
                 String objectToWrite)
          throws IOException

Description copied from interface: DictionaryWriter

Writes an object to the dictionary.

Returns the index of the value that was just written. This is defined as the `int` value that can be passed into DictionaryWriter.get(int) such that it will return the same value back.

Specified by:

write in interface DictionaryWriter<String>

Parameters:

objectToWrite - object to be written to the dictionary

Returns:

index of the value that was just written

Throws:

IOException - if there is a problem with IO

get

@Nullable
public String get(int dictId)
           throws IOException

Description copied from interface: DictionaryWriter

Returns an object that has already been written via the DictionaryWriter.write(T) method.

Specified by:

get in interface DictionaryWriter<String>

Parameters:

dictId - index of the object to return

Returns:

the object identified by the given index

Throws:

IOException - if there is a problem with IO

getCardinality

public int getCardinality()

Description copied from interface: DictionaryWriter

Returns the number of items that have been written so far in this dictionary. Any number lower than this cardinality can be passed into DictionaryWriter.get(int) and a value will be returned. If a value greater than or equal to the cardinality is passed into DictionaryWriter.get(int) all sorts of things could happen, but likely none of them are good.

Specified by:

getCardinality in interface DictionaryWriter<String>

Returns:

the number of items that have been written so far

getSerializedSize

public long getSerializedSize()
                       throws IOException

Description copied from interface: Serializer

Returns the number of bytes, that this Serializer will write to the output _channel_ (not smoosher) on a Serializer.writeTo(java.nio.channels.WritableByteChannel, org.apache.druid.java.util.common.io.smoosh.FileSmoosher) call.

Specified by:

getSerializedSize in interface Serializer

Throws:

IOException

writeTo

public void writeTo(WritableByteChannel channel,
                    FileSmoosher smoosher)
             throws IOException

Description copied from interface: Serializer

Writes the serialized form of this object. The entire object may be written to the provided channel, or the object may be split over the provided channel and files added to the {@link FileSmoosher], where additional channels can be created via FileSmoosher.addWithSmooshedWriter(String, long). The latter approach is useful when the serialized form of the object is too large for a single smoosh container. At the time this javadoc was written, the max smoosh container size is limit to the max ByteBuffer size.

Specified by:

writeTo in interface Serializer

Throws:

IOException