alluxio.collections

Interface FieldIndex<T>

Type Parameters:

T - type of objects in IndexedSet

All Superinterfaces:

Iterable<T>

All Known Implementing Classes:

NonUniqueFieldIndex, UniqueFieldIndex

public interface FieldIndex<T>
extends Iterable<T>

An interface representing an index for IndexedSet, each index for this set must implement the interface to define how to get the value of the field chosen as the index. Users must use the same instance of the implementation of this interface as the parameter in all methods of IndexedSet to represent the same index.

Method Summary

Modifier and Type	Method and Description
boolean	add(T o) Adds an object o to the index.
void	clear() Removes all the entries in this index.
boolean	containsField(Object fieldValue) Returns whether there is an object with the specified index field value in the set.
boolean	containsObject(T o) Returns whether there is an object in the set.
Set<T>	getByField(Object value) Gets a subset of objects with the specified field value.
T	getFirst(Object value) Gets an object from the set of objects with the specified field value.
Iterator<T>	iterator() Returns an iterator over the elements in this index.
boolean	remove(T o) Removes the object o from the index.
int	size()

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Method Detail

add

boolean add(T o)

Adds an object o to the index.

Parameters:

o - the object to add to the index

Returns:

true if object is added successfully, false otherwise

remove

boolean remove(T o)

Removes the object o from the index.

Parameters:

o - the object to remove from index

Returns:

whether the specified element was in the index

clear

void clear()

Removes all the entries in this index.

containsField

boolean containsField(Object fieldValue)

Returns whether there is an object with the specified index field value in the set.

Parameters:

fieldValue - the field value to be satisfied

Returns:

true if there is one such object, otherwise false

containsObject

boolean containsObject(T o)

Returns whether there is an object in the set.

Parameters:

o - the object to be checked

Returns:

true if there is one such object, otherwise false

getByField

Set<T> getByField(Object value)

Gets a subset of objects with the specified field value. If there is no object with the specified field value, an empty set is returned.

Parameters:

value - the field value to be satisfied

Returns:

the set of objects or an empty set if no such object exists

getFirst

T getFirst(Object value)

Gets an object from the set of objects with the specified field value.

Parameters:

value - the field value to be satisfied

Returns:

the object or null if there is no such object

iterator

Iterator<T> iterator()

Returns an iterator over the elements in this index. The elements are returned in no particular order. Note that the behavior of the iterator is unspecified if the underlying collection is modified while a thread is going through the iterator.

Specified by:

iterator in interface Iterable<T>

Returns:

an iterator over the elements in this FieldIndex

size

int size()

Returns:

the number of objects in this index set