Function1 (Apache Calcite API)

Type Parameters:

R - Result type

T0 - Type of parameter 0

All Superinterfaces:

Function<R>

All Known Subinterfaces:

BigDecimalFunction1<T0>, NullableBigDecimalFunction1<T0>, NullableDoubleFunction1<T0>, NullableFloatFunction1<T0>, NullableIntegerFunction1<T0>, NullableLongFunction1<T0>, RelProtoDataType

All Known Implementing Classes:

DruidTable.MapRelProtoDataType, Functions.Ignore, ReflectiveSchema.FieldSelector
```
public interface Function1<T0,R>
extends Function<R>
```
Function with one parameter.

- Field Summary
  
  Fields
  Modifier and Type Field Description
  
  static Function1<java.lang.Object,java.lang.Object> IDENTITY
  The identity function.
- Method Summary
  
  All Methods Instance Methods Abstract Methods
  Modifier and Type Method Description
  
  R apply(T0 a0)

- Field Detail
  - IDENTITY
```
static final Function1<java.lang.Object,java.lang.Object> IDENTITY
```
    The identity function.
    
    See Also:
    
    Functions.identitySelector()
- Method Detail
  - apply
```
R apply(T0 a0)
```