java.lang.Object
- org.apache.druid.segment.column.RowSignature

All Implemented Interfaces:

Expr.InputBindingInspector, ColumnInspector
```
public class RowSignature
extends Object
implements ColumnInspector
```
Type signature for a row in a Druid datasource or query result.

See Also:

which returns signatures for query results, which returns signatures for inline datasources

Nested Class Summary

Nested Classes
Modifier and Type Class Description

static class RowSignature.Builder

static class RowSignature.Finalization

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`static RowSignature.Builder`	`builder()`
`boolean`	`contains(int columnNumber)`
`boolean`	`contains(String columnName)`	Returns whether this signature contains a named column.
`static RowSignature`	`empty()`
`boolean`	`equals(Object o)`
`ColumnCapabilities`	`getColumnCapabilities(String column)`	Returns capabilities of a particular column.
`String`	`getColumnName(int columnNumber)`	Returns the name of the column at position `columnNumber`.
`List<String>`	`getColumnNames()`	Returns a list of column names in the order they appear in this signature.
`Optional<ColumnType>`	`getColumnType(int columnNumber)`	Returns the type of the column at position `columnNumber`, or empty if the type is unknown.
`Optional<ColumnType>`	`getColumnType(String columnName)`	Returns the type of the column named `columnName`, or empty if the type is unknown or the column does not exist.
`int`	`hashCode()`
`int`	`indexOf(String columnName)`	Returns the first position of `columnName` in this row signature, or -1 if it does not appear.
`boolean`	`isNumeric(String columnName)`	Returns true if the column is a numeric type (`TypeSignature.isNumeric()`), otherwise false if the column is not a numeric type or is not present in the row signature.
`int`	`size()`	Returns the number of columns in this signature.
`String`	`toString()`

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.apache.druid.segment.ColumnInspector
getColumnCapabilitiesWithDefault, getType

Methods inherited from interface org.apache.druid.math.expr.Expr.InputBindingInspector
areNumeric, areNumeric, areSameTypes, areSameTypes, areScalar, areScalar, canVectorize, canVectorize

- Method Detail
  - builder
```
public static RowSignature.Builder builder()
```
  - empty
```
public static RowSignature empty()
```
  - getColumnName
```
public String getColumnName(int columnNumber)
```
    Returns the name of the column at position columnNumber.
    
    Throws:
    
    IndexOutOfBoundsException - if columnNumber is not within our row length
  - getColumnType
```
public Optional<ColumnType> getColumnType(String columnName)
```
    Returns the type of the column named columnName, or empty if the type is unknown or the column does not exist.
  - getColumnType
```
public Optional<ColumnType> getColumnType(int columnNumber)
```
    Returns the type of the column at position columnNumber, or empty if the type is unknown.
    
    Throws:
    
    IndexOutOfBoundsException - if columnNumber is not within our row length
  - isNumeric
```
public boolean isNumeric(String columnName)
```
    Returns true if the column is a numeric type (TypeSignature.isNumeric()), otherwise false if the column is not a numeric type or is not present in the row signature.
  - getColumnNames
```
public List<String> getColumnNames()
```
    Returns a list of column names in the order they appear in this signature.
  - size
```
public int size()
```
    Returns the number of columns in this signature.
  - contains
```
public boolean contains(String columnName)
```
    Returns whether this signature contains a named column.
  - contains
```
public boolean contains(int columnNumber)
```
  - indexOf
```
public int indexOf(String columnName)
```
    Returns the first position of columnName in this row signature, or -1 if it does not appear. Note: the same column name may appear more than once in a signature; if it does, this method will return the first appearance.
  - equals
```
public boolean equals(Object o)
```
    Overrides:
    
    equals in class Object
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class Object
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object
  - getColumnCapabilities
```
@Nullable
public ColumnCapabilities getColumnCapabilities(String column)
```
    Description copied from interface: ColumnInspector
    
    Returns capabilities of a particular column.
    
    Specified by:
    
    getColumnCapabilities in interface ColumnInspector
    
    Parameters:
    
    column - column name
    
    Returns:
    
    capabilities, or null

Modifier and Type	Class	Description
`static class`	`RowSignature.Builder`
`static class`	`RowSignature.Finalization`

Class RowSignature

Nested Class Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface org.apache.druid.segment.ColumnInspector

Methods inherited from interface org.apache.druid.math.expr.Expr.InputBindingInspector

Method Detail

builder

empty

getColumnName

getColumnType

getColumnType

isNumeric

getColumnNames

size

contains

contains

indexOf

equals

hashCode

toString

getColumnCapabilities