java.lang.Object
- org.apache.flink.api.common.operators.util.FieldSet

All Implemented Interfaces:

Iterable<Integer>

Direct Known Subclasses:

FieldList
```
@Internal
public class FieldSet
extends Object
implements Iterable<Integer>
```
Immutable unordered collection of fields IDs.

Field Summary

Fields
Modifier and Type Field Description

protected Collection<Integer> collection

static FieldSet EMPTY_SET

Constructor Summary

Constructors
Modifier	Constructor	Description
	`FieldSet()`	Creates a new empty set of fields.
	`FieldSet(int... fieldIDs)`	Creates a set with the given fields.
	`FieldSet(int[] fieldIDs, boolean marker)`	Creates a set with the given fields.
	`FieldSet(Integer fieldID)`	Creates a set with one field.
`protected`	`FieldSet(Collection<Integer> fields)`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`FieldSet`	`addField(Integer fieldID)`
`FieldSet`	`addFields(int... fieldIDs)`
`FieldSet`	`addFields(FieldSet set)`
`FieldSet`	`clone()`	Since instances of FieldSet are strictly immutable, this method does not actually clone, but it only returns the original instance.
`boolean`	`contains(Integer columnIndex)`
`boolean`	`equals(Object obj)`
`protected String`	`getDescriptionPrefix()`
`protected String`	`getDescriptionSuffix()`
`int`	`hashCode()`
`boolean`	`isValidSubset(FieldSet set)`	Checks if the given set of fields is a valid subset of this set of fields.
`Iterator<Integer>`	`iterator()`
`int`	`size()`
`int[]`	`toArray()`	Transforms the field set into an array of field IDs.
`FieldList`	`toFieldList()`	Turns the FieldSet into an ordered FieldList.
`String`	`toString()`

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

Methods inherited from interface java.lang.Iterable
forEach, spliterator

- Field Detail
  - EMPTY_SET
```
public static final FieldSet EMPTY_SET
```
  - collection
```
protected final Collection<Integer> collection
```
- Constructor Detail
  - FieldSet
```
public FieldSet()
```
    Creates a new empty set of fields.
  - FieldSet
```
public FieldSet(Integer fieldID)
```
    Creates a set with one field.
    
    Parameters:
    
    fieldID - The id of the field.
  - FieldSet
```
public FieldSet(int... fieldIDs)
```
    Creates a set with the given fields.
    
    Parameters:
    
    fieldIDs - The IDs of the fields.
  - FieldSet
```
public FieldSet(int[] fieldIDs,
                boolean marker)
```
    Creates a set with the given fields.
    
    Parameters:
    
    fieldIDs - The IDs of the fields.
  - FieldSet
```
protected FieldSet(Collection<Integer> fields)
```
- Method Detail
  - addField
```
public FieldSet addField(Integer fieldID)
```
  - addFields
```
public FieldSet addFields(int... fieldIDs)
```
  - addFields
```
public FieldSet addFields(FieldSet set)
```
  - contains
```
public boolean contains(Integer columnIndex)
```
  - size
```
public int size()
```
  - iterator
```
public Iterator<Integer> iterator()
```
    Specified by:
    
    iterator in interface Iterable<Integer>
  - toFieldList
```
public FieldList toFieldList()
```
    Turns the FieldSet into an ordered FieldList.
    
    Returns:
    
    An ordered FieldList.
  - toArray
```
public int[] toArray()
```
    Transforms the field set into an array of field IDs. Whether the IDs are ordered or unordered depends on the specific subclass of the field set.
    
    Returns:
    
    An array of all contained field IDs.
  - isValidSubset
```
public boolean isValidSubset(FieldSet set)
```
    Checks if the given set of fields is a valid subset of this set of fields. For unordered sets, this is the case if all of the given set's fields are also part of this field.
    Subclasses that describe field sets where the field order matters must override this method to implement a field ordering sensitive check.
    
    Parameters:
    
    set - The set that is a candidate subset.
    
    Returns:
    
    True, if the given set is a subset of this set, false otherwise.
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class Object
  - equals
```
public boolean equals(Object obj)
```
    Overrides:
    
    equals in class Object
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object
  - clone
```
public FieldSet clone()
```
    Since instances of FieldSet are strictly immutable, this method does not actually clone, but it only returns the original instance.
    
    Overrides:
    
    clone in class Object
    
    Returns:
    
    This objects reference, unmodified.
  - getDescriptionPrefix
```
protected String getDescriptionPrefix()
```
  - getDescriptionSuffix
```
protected String getDescriptionSuffix()
```

Modifier and Type	Field	Description
`protected Collection<Integer>`	`collection`
`static FieldSet`	`EMPTY_SET`

Class FieldSet

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface java.lang.Iterable

Field Detail

EMPTY_SET

collection

Constructor Detail

FieldSet

FieldSet

FieldSet

FieldSet

FieldSet

Method Detail

addField

addFields

addFields

contains

size

iterator

toFieldList

toArray

isValidSubset

hashCode

equals

toString

clone

getDescriptionPrefix

getDescriptionSuffix