Package com.esotericsoftware.kryo.util

Class MapReferenceResolver

java.lang.Object

com.esotericsoftware.kryo.util.MapReferenceResolver

All Implemented Interfaces:

ReferenceResolver

public class MapReferenceResolver
extends Object
implements ReferenceResolver

Uses an IdentityObjectIntMap to track objects that have already been written. This can handle a graph with any number of objects, but is slightly slower than ListReferenceResolver for graphs with few objects. Compared to HashMapReferenceResolver, this may provide better performance since the IdentityObjectIntMap does not normally allocate for get or put.

Author:

Nathan Sweet

Field Summary

Fields

Modifier and Type	Field	Description
protected Kryo	kryo
protected ArrayList<Object>	readObjects
protected IdentityObjectIntMap<Object>	writtenObjects

Constructor Summary

Constructors

Constructor	Description
MapReferenceResolver()	Creates a reference resolver with a default maximum capacity of 2048
MapReferenceResolver(int maximumCapacity)	Creates a reference resolver with the specified maximum capacity.

Method Summary

Modifier and Type	Method	Description
int	addWrittenObject(Object object)	Returns a new ID for an object that is being written for the first time.
Object	getReadObject(Class type, int id)	Returns the object for the specified ID.
int	getWrittenId(Object object)	Returns an ID for the object if it has been written previously, otherwise returns -1.
int	nextReadId(Class type)	Reserves the ID for the next object that will be read.
void	reset()	Called by Kryo.reset().
void	setKryo(Kryo kryo)	Sets the Kryo instance that this ClassResolver will be used for.
void	setReadObject(int id, Object object)	Sets the ID for an object that has been read.
boolean	useReferences(Class type)	Returns false for all primitive wrappers and enums.

Methods inherited from class java.lang.Object

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

Field Detail

kryo

protected Kryo kryo

writtenObjects

protected final IdentityObjectIntMap<Object> writtenObjects

readObjects

protected final ArrayList<Object> readObjects

Constructor Detail

MapReferenceResolver

public MapReferenceResolver()

Creates a reference resolver with a default maximum capacity of 2048

MapReferenceResolver

public MapReferenceResolver(int maximumCapacity)

Creates a reference resolver with the specified maximum capacity. The default value of 2048 is good enough in most cases. If the average object graph is larger than the default, increasing this value can provide better performance.

Parameters:

maximumCapacity - the capacity to trim written and read objects to when reset() is called

Method Detail

setKryo

public void setKryo(Kryo kryo)

Description copied from interface: ReferenceResolver

Sets the Kryo instance that this ClassResolver will be used for. This is called automatically by Kryo.

Specified by:

setKryo in interface ReferenceResolver

addWrittenObject

public int addWrittenObject(Object object)

Description copied from interface: ReferenceResolver

Returns a new ID for an object that is being written for the first time.

Specified by:

addWrittenObject in interface ReferenceResolver

Returns:

The ID, which is stored more efficiently if it is positive and must not be -1 or -2.

getWrittenId

public int getWrittenId(Object object)

Description copied from interface: ReferenceResolver

Returns an ID for the object if it has been written previously, otherwise returns -1.

Specified by:

getWrittenId in interface ReferenceResolver

nextReadId

public int nextReadId(Class type)

Description copied from interface: ReferenceResolver

Reserves the ID for the next object that will be read. This is called only the first time an object is encountered.

Specified by:

nextReadId in interface ReferenceResolver

Parameters:

type - The type of object that will be read.

Returns:

The ID, which is stored more efficiently if it is positive and must not be -1 or -2.

setReadObject

public void setReadObject(int id,
                          Object object)

Description copied from interface: ReferenceResolver

Sets the ID for an object that has been read.

Specified by:

setReadObject in interface ReferenceResolver

Parameters:

id - The ID from ReferenceResolver.nextReadId(Class).

getReadObject

public Object getReadObject(Class type,
                            int id)

Description copied from interface: ReferenceResolver

Returns the object for the specified ID. The ID and object are guaranteed to have been previously passed in a call to ReferenceResolver.setReadObject(int, Object).

Specified by:

getReadObject in interface ReferenceResolver

reset

public void reset()

Description copied from interface: ReferenceResolver

Called by Kryo.reset().

Specified by:

reset in interface ReferenceResolver

useReferences

public boolean useReferences(Class type)

Returns false for all primitive wrappers and enums.

Specified by:

useReferences in interface ReferenceResolver

Parameters:

type - Will never be a primitive type, but may be a primitive type wrapper.