org.apache.flink.streaming.util.typeutils

Class FieldAccessor<T,F>

java.lang.Object

org.apache.flink.streaming.util.typeutils.FieldAccessor<T,F>

All Implemented Interfaces:

Serializable

@Internal
public abstract class FieldAccessor<T,F>
extends Object
implements Serializable

These classes encapsulate the logic of accessing a field specified by the user as either an index or a field expression string. TypeInformation can also be requested for the field. The position index might specify a field of a Tuple, an array, or a simple type(only "0th field").

Field expressions that specify nested fields (e.g. "f1.a.foo") result in nested field accessors. These penetrate one layer, and then delegate the rest of the work to an "innerAccessor". (see PojoFieldAccessor, RecursiveTupleFieldAccessor, RecursiveProductFieldAccessor)

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected TypeInformation	fieldType

Constructor Summary

Constructors

Constructor and Description
FieldAccessor()

Method Summary

Modifier and Type	Method and Description
abstract F	get(T record) Gets the value of the field (specified in the constructor) of the given record.
TypeInformation<F>	getFieldType() Gets the TypeInformation for the type of the field.
abstract T	set(T record, F fieldValue) Sets the field (specified in the constructor) of the given record to the given value.

Methods inherited from class java.lang.Object

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

Field Detail

fieldType

protected TypeInformation fieldType

Constructor Detail

FieldAccessor

public FieldAccessor()

Method Detail

getFieldType

public TypeInformation<F> getFieldType()

Gets the TypeInformation for the type of the field. Note: For an array of a primitive type, it returns the corresponding basic type (Integer for int[]).

get

public abstract F get(T record)

Gets the value of the field (specified in the constructor) of the given record.

Parameters:

record - The record on which the field will be accessed

Returns:

The value of the field.

set

public abstract T set(T record,
                      F fieldValue)

Sets the field (specified in the constructor) of the given record to the given value.

Warning: This might modify the original object, or might return a new object instance. (This is necessary, because the record might be immutable.)

Parameters:

record - The record to modify

fieldValue - The new value of the field

Returns:

A record that has the given field value. (this might be a new instance or the original)