alluxio.collections

Class UniqueFieldIndex<T,V>

java.lang.Object

alluxio.collections.UniqueFieldIndex<T,V>

Type Parameters:

T - type of objects in this index

V - type of the field used for indexing

All Implemented Interfaces:

FieldIndex<T,V>, Iterable<T>

@ThreadSafe
public class UniqueFieldIndex<T,V>
extends Object
implements FieldIndex<T,V>

A class representing a unique index. A unique index is an index where each index value only maps to one object.

Constructor Summary

Constructors

Constructor and Description
UniqueFieldIndex(IndexDefinition<T,V> indexDefinition) Constructs a new UniqueFieldIndex instance.

Method Summary

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

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Constructor Detail

UniqueFieldIndex

public UniqueFieldIndex(IndexDefinition<T,V> indexDefinition)

Constructs a new UniqueFieldIndex instance.

Parameters:

indexDefinition - definition of index

Method Detail

add

public boolean add(T object)

Description copied from interface: FieldIndex

Adds an object o to the index.

Specified by:

add in interface FieldIndex<T,V>

Parameters:

object - the object to add to the index

Returns:

true if object is added successfully, false otherwise

remove

public boolean remove(T object)

Description copied from interface: FieldIndex

Removes the object o from the index.

Specified by:

remove in interface FieldIndex<T,V>

Parameters:

object - the object to remove from index

Returns:

whether the specified element was in the index

clear

public void clear()

Description copied from interface: FieldIndex

Removes all the entries in this index.

Specified by:

clear in interface FieldIndex<T,V>

containsField

public boolean containsField(V fieldValue)

Description copied from interface: FieldIndex

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

Specified by:

containsField in interface FieldIndex<T,V>

Parameters:

fieldValue - the field value to be satisfied

Returns:

true if there is one such object, otherwise false

containsObject

public boolean containsObject(T object)

Description copied from interface: FieldIndex

Returns whether there is an object in the set.

Specified by:

containsObject in interface FieldIndex<T,V>

Parameters:

object - the object to be checked

Returns:

true if there is one such object, otherwise false

getByField

public Set<T> getByField(V value)

Description copied from interface: FieldIndex

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.

Specified by:

getByField in interface FieldIndex<T,V>

Parameters:

value - the field value to be satisfied

Returns:

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

getFirst

public T getFirst(V value)

Description copied from interface: FieldIndex

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

Specified by:

getFirst in interface FieldIndex<T,V>

Parameters:

value - the field value to be satisfied

Returns:

the object or null if there is no such object

iterator

public Iterator<T> iterator()

Description copied from interface: FieldIndex

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 FieldIndex<T,V>

Specified by:

iterator in interface Iterable<T>

Returns:

an iterator over the elements in this FieldIndex

size

public int size()

Specified by:

size in interface FieldIndex<T,V>

Returns:

the number of objects in this index set