Package com.google.appengine.api.datastore

Class KeyRange

java.lang.Object

com.google.appengine.api.datastore.KeyRange

All Implemented Interfaces:

Serializable, Iterable<Key>

public final class KeyRange
extends Object
implements Iterable<Key>, Serializable

Represents a range of unique datastore identifiers from getStart().getId() to getEnd().getId() inclusive. If an instance of this class is the result of a call to DatastoreService.allocateIds(), the Keys returned by this instance have been consumed in the datastore's id-space and are guaranteed never to be reused.
This class can be used to construct Entities with Keys that have specific id values without fear of the datastore creating new records with those same ids at a later date. This can be helpful as part of a data migration or large bulk upload where you may need to preserve existing ids and relationships between entities.
This class is threadsafe but the Iterators returned by iterator() are not.

See Also:

• Serialized Form

Constructor Summary

Constructors

Constructor	Description
KeyRange(Key parent, String kind, long start, long end)

Method Summary

Modifier and Type	Method	Description
boolean	equals(@Nullable Object obj)
Key	getEnd()	Returns the last Key in the range.
long	getSize()	Returns the size of the range.
Key	getStart()	Returns the first Key in the range.
int	hashCode()
Iterator<Key>	iterator()

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Constructor Details

KeyRange

public KeyRange(Key parent,
 String kind,
 long start,
 long end)

Method Details

getStart

public Key getStart()

Returns the first Key in the range.

getEnd

public Key getEnd()

Returns the last Key in the range.

getSize

public long getSize()

Returns the size of the range.

iterator

public Iterator<Key> iterator()

Specified by:

iterator in interface Iterable<Key>

equals

public boolean equals(@Nullable Object obj)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object