hydra.langs.parquet.format.Encoding Maven / Gradle / Ivy
package hydra.langs.parquet.format;
import java.io.Serializable;
/**
* Encodings supported by Parquet. Not all encodings are valid for all types. These enums are also used to specify the encoding of definition and repetition levels. See the accompanying doc for the details of the more complicated encodings.
*/
public abstract class Encoding implements Serializable {
public static final hydra.core.Name NAME = new hydra.core.Name("hydra/langs/parquet/format.Encoding");
private Encoding () {
}
public abstract R accept(Visitor visitor) ;
public interface Visitor {
R visit(Plain instance) ;
R visit(Rle instance) ;
R visit(BitPacked instance) ;
R visit(DeltaBinaryPacked instance) ;
R visit(DeltaLengthByteArray instance) ;
R visit(DeltaByteArray instance) ;
R visit(RleDictionary instance) ;
R visit(ByteStreamSplit instance) ;
}
public interface PartialVisitor extends Visitor {
default R otherwise(Encoding instance) {
throw new IllegalStateException("Non-exhaustive patterns when matching: " + (instance));
}
default R visit(Plain instance) {
return otherwise((instance));
}
default R visit(Rle instance) {
return otherwise((instance));
}
default R visit(BitPacked instance) {
return otherwise((instance));
}
default R visit(DeltaBinaryPacked instance) {
return otherwise((instance));
}
default R visit(DeltaLengthByteArray instance) {
return otherwise((instance));
}
default R visit(DeltaByteArray instance) {
return otherwise((instance));
}
default R visit(RleDictionary instance) {
return otherwise((instance));
}
default R visit(ByteStreamSplit instance) {
return otherwise((instance));
}
}
/**
* Default encoding.
* BOOLEAN - 1 bit per value. 0 is false; 1 is true.
* INT32 - 4 bytes per value. Stored as little-endian.
* INT64 - 8 bytes per value. Stored as little-endian.
* FLOAT - 4 bytes per value. IEEE. Stored as little-endian.
* DOUBLE - 8 bytes per value. IEEE. Stored as little-endian.
* BYTE_ARRAY - 4 byte length stored as little endian, followed by bytes.
* FIXED_LEN_BYTE_ARRAY - Just the bytes.
*/
public static final class Plain extends hydra.langs.parquet.format.Encoding implements Serializable {
public Plain () {
}
@Override
public boolean equals(Object other) {
if (!(other instanceof Plain)) {
return false;
}
Plain o = (Plain) (other);
return true;
}
@Override
public int hashCode() {
return 0;
}
@Override
public R accept(Visitor visitor) {
return visitor.visit(this);
}
}
/**
* Group packed run length encoding. Usable for definition/repetition levels encoding and Booleans (on one bit: 0 is false; 1 is true.)
*/
public static final class Rle extends hydra.langs.parquet.format.Encoding implements Serializable {
public Rle () {
}
@Override
public boolean equals(Object other) {
if (!(other instanceof Rle)) {
return false;
}
Rle o = (Rle) (other);
return true;
}
@Override
public int hashCode() {
return 0;
}
@Override
public R accept(Visitor visitor) {
return visitor.visit(this);
}
}
/**
* Bit packed encoding. This can only be used if the data has a known max width. Usable for definition/repetition levels encoding.
*/
public static final class BitPacked extends hydra.langs.parquet.format.Encoding implements Serializable {
public BitPacked () {
}
@Override
public boolean equals(Object other) {
if (!(other instanceof BitPacked)) {
return false;
}
BitPacked o = (BitPacked) (other);
return true;
}
@Override
public int hashCode() {
return 0;
}
@Override
public R accept(Visitor visitor) {
return visitor.visit(this);
}
}
/**
* Delta encoding for integers. This can be used for int columns and works best on sorted data
*/
public static final class DeltaBinaryPacked extends hydra.langs.parquet.format.Encoding implements Serializable {
public DeltaBinaryPacked () {
}
@Override
public boolean equals(Object other) {
if (!(other instanceof DeltaBinaryPacked)) {
return false;
}
DeltaBinaryPacked o = (DeltaBinaryPacked) (other);
return true;
}
@Override
public int hashCode() {
return 0;
}
@Override
public R accept(Visitor visitor) {
return visitor.visit(this);
}
}
/**
* Encoding for byte arrays to separate the length values and the data. The lengths are encoded using DELTA_BINARY_PACKED
*/
public static final class DeltaLengthByteArray extends hydra.langs.parquet.format.Encoding implements Serializable {
public DeltaLengthByteArray () {
}
@Override
public boolean equals(Object other) {
if (!(other instanceof DeltaLengthByteArray)) {
return false;
}
DeltaLengthByteArray o = (DeltaLengthByteArray) (other);
return true;
}
@Override
public int hashCode() {
return 0;
}
@Override
public R accept(Visitor visitor) {
return visitor.visit(this);
}
}
/**
* Incremental-encoded byte array. Prefix lengths are encoded using DELTA_BINARY_PACKED. Suffixes are stored as delta length byte arrays.
*/
public static final class DeltaByteArray extends hydra.langs.parquet.format.Encoding implements Serializable {
public DeltaByteArray () {
}
@Override
public boolean equals(Object other) {
if (!(other instanceof DeltaByteArray)) {
return false;
}
DeltaByteArray o = (DeltaByteArray) (other);
return true;
}
@Override
public int hashCode() {
return 0;
}
@Override
public R accept(Visitor visitor) {
return visitor.visit(this);
}
}
/**
* Dictionary encoding: the ids are encoded using the RLE encoding
*/
public static final class RleDictionary extends hydra.langs.parquet.format.Encoding implements Serializable {
public RleDictionary () {
}
@Override
public boolean equals(Object other) {
if (!(other instanceof RleDictionary)) {
return false;
}
RleDictionary o = (RleDictionary) (other);
return true;
}
@Override
public int hashCode() {
return 0;
}
@Override
public R accept(Visitor visitor) {
return visitor.visit(this);
}
}
/**
* Encoding for floating-point data. K byte-streams are created where K is the size in bytes of the data type. The individual bytes of an FP value are scattered to the corresponding stream and the streams are concatenated. This itself does not reduce the size of the data but can lead to better compression afterwards.
*/
public static final class ByteStreamSplit extends hydra.langs.parquet.format.Encoding implements Serializable {
public ByteStreamSplit () {
}
@Override
public boolean equals(Object other) {
if (!(other instanceof ByteStreamSplit)) {
return false;
}
ByteStreamSplit o = (ByteStreamSplit) (other);
return true;
}
@Override
public int hashCode() {
return 0;
}
@Override
public R accept(Visitor visitor) {
return visitor.visit(this);
}
}
} © 2015 - 2025 Weber Informatics LLC | Privacy Policy