alluxio.collections

Class IndexDefinition<T>

java.lang.Object

alluxio.collections.IndexDefinition<T>

Type Parameters:

T - type of objects in this IndexedSet

@ThreadSafe
public abstract class IndexDefinition<T>
extends Object

A class representing the definition of an index for this IndexedSet. Each instance of this class must implement the method to define how to get the value of the field chosen as the index key. Users use this indexDefinition class as the parameter in all methods of IndexedSet to represent an index.

Constructor Summary

Constructors

Constructor and Description
IndexDefinition(boolean isUnique) Constructs a new IndexDefinition instance.

Method Summary

Modifier and Type	Method and Description
abstract Object	getFieldValue(T o) Gets the value of the field that serves as index.
boolean	isUnique()

Methods inherited from class java.lang.Object

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

Constructor Detail

IndexDefinition

public IndexDefinition(boolean isUnique)

Constructs a new IndexDefinition instance.

Parameters:

isUnique - whether the index is unique. A unique index is an index where each index value only maps to one object; A non-unique index is an index where an index value can map to one or more objects.

Method Detail

isUnique

public boolean isUnique()

Returns:

whether the index requires all field values to be unique

getFieldValue

public abstract Object getFieldValue(T o)

Gets the value of the field that serves as index.

Parameters:

o - the instance to get the field value from

Returns:

the field value