io.druid.segment

Class StringDimensionHandler

java.lang.Object

io.druid.segment.StringDimensionHandler

All Implemented Interfaces:

DimensionHandler<Integer,int[],String>

public class StringDimensionHandler
extends Object
implements DimensionHandler<Integer,int[],String>

Constructor Summary

Constructors

Constructor and Description
StringDimensionHandler(String dimensionName, DimensionSchema.MultiValueHandling multiValueHandling)

Method Summary

Modifier and Type	Method and Description
int	compareSortedEncodedKeyComponents(int[] lhs, int[] rhs) Given two key components representing sorted encoded row value(s), return the result of their comparison.
String	getDimensionName() Get the name of the column associated with this handler.
int[]	getEncodedKeyComponentFromColumn(Closeable column, int currRow) Given a subcolumn from getSubColumn, and the index of the current row, retrieve a dimension's values from a row as an EncodedKeyComponentType.
int	getLengthOfEncodedKeyComponent(int[] dimVals) Given an key component representing a single set of row value(s) for this dimension as an Object, return the length of the key component after appropriate type-casting.
DimensionSchema.MultiValueHandling	getMultivalueHandling() Get DimensionSchema.MultiValueHandling for the column associated with this handler.
Closeable	getSubColumn(Column column) Given a Column, return a type-specific object that can be used to retrieve row values.
DimensionIndexer<Integer,int[],String>	makeIndexer() Creates a new DimensionIndexer, a per-dimension object responsible for processing ingested rows in-memory, used by the IncrementalIndex.
DimensionMergerV9	makeMerger(IndexSpec indexSpec, SegmentWriteOutMedium segmentWriteOutMedium, ColumnCapabilities capabilities, ProgressIndicator progress) Creates a new DimensionMergerV9, a per-dimension object responsible for merging indexes/row data across segments and building the on-disk representation of a dimension.
void	validateSortedEncodedKeyComponents(int[] lhs, int[] rhs, Indexed<String> lhsEncodings, Indexed<String> rhsEncodings) Given two key components representing sorted encoded row value(s), check that the two key components have the same encoded values, or if the encoded values differ, that they translate into the same actual values, using the mappings provided by lhsEncodings and rhsEncodings (if applicable).

Methods inherited from class java.lang.Object

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

Constructor Detail

StringDimensionHandler

public StringDimensionHandler(String dimensionName,
                              DimensionSchema.MultiValueHandling multiValueHandling)

Method Detail

getDimensionName

public String getDimensionName()

Description copied from interface: DimensionHandler

Get the name of the column associated with this handler. This string would be the output name of the column during ingestion, and the name of an input column when querying.

Specified by:

getDimensionName in interface DimensionHandler<Integer,int[],String>

Returns:

Dimension name

getMultivalueHandling

public DimensionSchema.MultiValueHandling getMultivalueHandling()

Description copied from interface: DimensionHandler

Get DimensionSchema.MultiValueHandling for the column associated with this handler. Only string columns can have DimensionSchema.MultiValueHandling currently.

Specified by:

getMultivalueHandling in interface DimensionHandler<Integer,int[],String>

getLengthOfEncodedKeyComponent

public int getLengthOfEncodedKeyComponent(int[] dimVals)

Description copied from interface: DimensionHandler

Given an key component representing a single set of row value(s) for this dimension as an Object, return the length of the key component after appropriate type-casting. For example, a dictionary encoded String dimension would receive an int[] as input to this method, while a Long numeric dimension would receive a single Long object (no multivalue support)

Specified by:

getLengthOfEncodedKeyComponent in interface DimensionHandler<Integer,int[],String>

Parameters:

dimVals - Values for this dimension from a row

Returns:

Size of dimVals

compareSortedEncodedKeyComponents

public int compareSortedEncodedKeyComponents(int[] lhs,
                                             int[] rhs)

Description copied from interface: DimensionHandler

Given two key components representing sorted encoded row value(s), return the result of their comparison. If the two key components have different lengths, the shorter component should be ordered first in the comparison. Otherwise, this function should iterate through the key components and return the comparison of the first difference. For dimensions that do not support multivalue rows, lhs and rhs can be compared directly.

Specified by:

compareSortedEncodedKeyComponents in interface DimensionHandler<Integer,int[],String>

Parameters:

lhs - key component from a row

rhs - key component from a row

Returns:

integer indicating comparison result of key components

validateSortedEncodedKeyComponents

public void validateSortedEncodedKeyComponents(int[] lhs,
                                               int[] rhs,
                                               Indexed<String> lhsEncodings,
                                               Indexed<String> rhsEncodings)
                                        throws SegmentValidationException

Description copied from interface: DimensionHandler

Given two key components representing sorted encoded row value(s), check that the two key components have the same encoded values, or if the encoded values differ, that they translate into the same actual values, using the mappings provided by lhsEncodings and rhsEncodings (if applicable). If validation fails, this method should throw a SegmentValidationException. Used by IndexIO for validating segments. See StringDimensionHandler.validateSortedEncodedKeyComponents() for a reference implementation.

Specified by:

validateSortedEncodedKeyComponents in interface DimensionHandler<Integer,int[],String>

Parameters:

lhs - key component from a row

rhs - key component from a row

lhsEncodings - encoding lookup from lhs's segment, null if not applicable for this dimension's type

rhsEncodings - encoding lookup from rhs's segment, null if not applicable for this dimension's type

Throws:

SegmentValidationException

getSubColumn

public Closeable getSubColumn(Column column)

Description copied from interface: DimensionHandler

Given a Column, return a type-specific object that can be used to retrieve row values. For example: - A String-typed implementation would return the result of column.getDictionaryEncoding() - A long-typed implemention would return the result of column.getGenericColumn().

Specified by:

getSubColumn in interface DimensionHandler<Integer,int[],String>

Parameters:

column - Column for this dimension from a QueryableIndex

Returns:

The type-specific column subobject for this dimension.

getEncodedKeyComponentFromColumn

public int[] getEncodedKeyComponentFromColumn(Closeable column,
                                              int currRow)

Description copied from interface: DimensionHandler

Given a subcolumn from getSubColumn, and the index of the current row, retrieve a dimension's values from a row as an EncodedKeyComponentType. For example: - A String-typed implementation would read the current row from a DictionaryEncodedColumn as an int[]. - A long-typed implemention would read the current row from a GenericColumn and return a Long.

Specified by:

getEncodedKeyComponentFromColumn in interface DimensionHandler<Integer,int[],String>

Parameters:

column - Column for this dimension from a QueryableIndex

currRow - The index of the row to retrieve

Returns:

The key component for this dimension from the current row of the column.

makeIndexer

public DimensionIndexer<Integer,int[],String> makeIndexer()

Description copied from interface: DimensionHandler

Creates a new DimensionIndexer, a per-dimension object responsible for processing ingested rows in-memory, used by the IncrementalIndex. See DimensionIndexer interface for more information.

Specified by:

makeIndexer in interface DimensionHandler<Integer,int[],String>

Returns:

A new DimensionIndexer object.

makeMerger

public DimensionMergerV9 makeMerger(IndexSpec indexSpec,
                                    SegmentWriteOutMedium segmentWriteOutMedium,
                                    ColumnCapabilities capabilities,
                                    ProgressIndicator progress)

Description copied from interface: DimensionHandler

Creates a new DimensionMergerV9, a per-dimension object responsible for merging indexes/row data across segments and building the on-disk representation of a dimension. For use with IndexMergerV9 only. See DimensionMergerV9 interface for more information.

Specified by:

makeMerger in interface DimensionHandler<Integer,int[],String>

Parameters:

indexSpec - Specification object for the index merge

segmentWriteOutMedium - this SegmentWriteOutMedium object could be used internally in the created merger, if needed

capabilities - The ColumnCapabilities of the dimension represented by this DimensionHandler

progress - ProgressIndicator used by the merging process

Returns:

A new DimensionMergerV9 object.