org.jadira.reflection.cloning

Class MinimalCloner

java.lang.Object

org.jadira.reflection.cloning.MinimalCloner

All Implemented Interfaces:

CloneDriver, CloneImplementor, Cloner

public class MinimalCloner
extends Object
implements Cloner, CloneDriver, CloneImplementor

This is a highly reduced version of Cloner. It can deliver somewhat better throughput than UnsafeCloneStrategy using the Server JVM, and around twice the throughput of the PortableCloneStrategy. Unlike BasicCloner, this cloner does not offer any configuration options. Due to lack of configuration and special functions, this cloner is unsuitable for many datatypes. Note that MinimalCloner can be slower for certain kinds of data structure. For example, when cloning a linked list, MinimalCloner must visit all the references of the entire data structure, whereas other Cloners can use a CloneImplementor to perform efficient cloning of this structure iteratively. In general, you are recommended to use MinimalCloner judiciously. Typically you can use it by designating a data type as @Cloneable(implementor=MinimalCloner.class) so that the type known to benefit from this cloner makes use of it.

Constructor Summary

Constructors

Constructor and Description
MinimalCloner()

Method Summary

Modifier and Type	Method and Description
boolean	canClone(Class<?> clazz) Always returns true
<T> T	clone(T obj) Clones the supplied object
<T> T	clone(T obj, CloneDriver context, IdentityHashMap<Object,Object> referencesToReuse, long stackDepth) Performs a clone.
CloneImplementor	getAnnotationImplementor(Class<?> clazz) Cloneable annotation is not supported
CloneImplementor	getBuiltInImplementor(Class<?> clazz) Gets the built in implementor for the given class
MethodHandle	getCloneMethod(Class<?> clazz) Cloneable interface is not supported
Set<Class<?>>	getImmutableClasses() No Immutable classes are identified
CloneImplementor	getImplementor(Class<?> clazz) This implementation does not delegate to implementors
Set<Class<?>>	getNonCloneableClasses() No Non-Cloneable classes are identified
void	initialiseFor(Class<?> classes) This method is included simply so that cold starts can be avoided.
boolean	isCloneImmutable() Immutable fields are always cloned, but object reference identity in the new structure is preserved
boolean	isCloneSyntheticFields() Does not clone synthetic fields
boolean	isCloneTransientAnnotatedFields() Transient annotated fields are always cloned
boolean	isCloneTransientFields() Transient fields are always cloned
boolean	isImmutableInstance(Object instance) Indicates whether the given object instance should be treated as immutable
boolean	isTrackReferences() Indicates whether to track references
boolean	isTrackReferencesForFlatClasses() Indicates whether to also track references for flat classes when tracking references.
boolean	isUseCloneable() This implementation cannot invoke clone()
boolean	isUseCloneImplementors() CloneImplementors may not be used
<T> T	newInstance(Class<T> c) Create a new, uninitialised instance of the given class (if supported).
void	putAnnotationImplementor(Class<?> clazz, CloneImplementor implementor) Put the registered implementor for the given class
void	putCloneMethod(Class<?> clazz, MethodHandle handle) Put the clone() method for the indicated class
void	putImmutableInstance(Object instance) Stores an object instance to be treated as immutable

Methods inherited from class java.lang.Object

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

Constructor Detail

MinimalCloner

public MinimalCloner()

Method Detail

newInstance

public <T> T newInstance(Class<T> c)

Description copied from interface: CloneImplementor

Create a new, uninitialised instance of the given class (if supported). Depending on strategy, this may or may not initialise instance fields, and may or may not invoke constructors.

Specified by:

newInstance in interface CloneImplementor

Type Parameters:

T - The type of the instance to be constructed

Parameters:

c - Type to create instance of

Returns:

The new instance

canClone

public boolean canClone(Class<?> clazz)

Always returns true

Specified by:

canClone in interface CloneImplementor

Parameters:

clazz - The class

Returns:

True if cloneable, false otherwise

clone

public <T> T clone(T obj,
                   CloneDriver context,
                   IdentityHashMap<Object,Object> referencesToReuse,
                   long stackDepth)

Description copied from interface: CloneImplementor

Performs a clone.

Specified by:

clone in interface CloneImplementor

Type Parameters:

T - The type of the object to be cloned

Parameters:

obj - Object to clone

context - The CloneDriver that initiated the request

referencesToReuse - Any references for objects already cloned to ensure reference identity is preserved

stackDepth - The number of objects already cloned in the current data structure

Returns:

The cloned object

getImplementor

public CloneImplementor getImplementor(Class<?> clazz)

This implementation does not delegate to implementors

Specified by:

getImplementor in interface CloneDriver

Parameters:

clazz - The class

Returns:

A CloneImplementor

isUseCloneable

public boolean isUseCloneable()

This implementation cannot invoke clone()

Specified by:

isUseCloneable in interface CloneDriver

Returns:

Default value is false

isCloneTransientFields

public boolean isCloneTransientFields()

Transient fields are always cloned

Specified by:

isCloneTransientFields in interface CloneDriver

Returns:

Default value is true

isCloneTransientAnnotatedFields

public boolean isCloneTransientAnnotatedFields()

Transient annotated fields are always cloned

Specified by:

isCloneTransientAnnotatedFields in interface CloneDriver

Returns:

Default value is false

isCloneImmutable

public boolean isCloneImmutable()

Immutable fields are always cloned, but object reference identity in the new structure is preserved

Specified by:

isCloneImmutable in interface CloneDriver

Returns:

Default value is false

getImmutableClasses

public Set<Class<?>> getImmutableClasses()

No Immutable classes are identified

Specified by:

getImmutableClasses in interface CloneDriver

Returns:

immutableClasses The immutable classes

getNonCloneableClasses

public Set<Class<?>> getNonCloneableClasses()

No Non-Cloneable classes are identified

Specified by:

getNonCloneableClasses in interface CloneDriver

Returns:

immutableClasses The classes which should be be cloned

isUseCloneImplementors

public boolean isUseCloneImplementors()

CloneImplementors may not be used

Specified by:

isUseCloneImplementors in interface CloneDriver

Returns:

Default value is true

clone

public <T> T clone(T obj)

Description copied from interface: Cloner

Clones the supplied object

Specified by:

clone in interface Cloner

Type Parameters:

T - The class of the object to be cloned

Parameters:

obj - The object

Returns:

A clone of the object

initialiseFor

public void initialiseFor(Class<?> classes)

Description copied from interface: Cloner

This method is included simply so that cold starts can be avoided. The method performs any initialisation needed in order to be able to subsequently process the class. If it is not called ahead of time the initialisation will be performed as part of the cloning operation. You only need to use this method in situations where a cold start is unacceptable

Specified by:

initialiseFor in interface Cloner

Parameters:

classes - Classes to perform initialisation for.

getAnnotationImplementor

public CloneImplementor getAnnotationImplementor(Class<?> clazz)

Cloneable annotation is not supported

Specified by:

getAnnotationImplementor in interface CloneDriver

Parameters:

clazz - The class

Returns:

A CloneImplementor

getCloneMethod

public MethodHandle getCloneMethod(Class<?> clazz)

Cloneable interface is not supported

Specified by:

getCloneMethod in interface CloneDriver

Parameters:

clazz - The class to obtain the method for

Returns:

The related MethodHandle

isCloneSyntheticFields

public boolean isCloneSyntheticFields()

Does not clone synthetic fields

Specified by:

isCloneSyntheticFields in interface CloneDriver

Returns:

cloneSyntheticFields Default is false

putAnnotationImplementor

public void putAnnotationImplementor(Class<?> clazz,
                                     CloneImplementor implementor)

Description copied from interface: CloneDriver

Put the registered implementor for the given class

Specified by:

putAnnotationImplementor in interface CloneDriver

Parameters:

clazz - The class

implementor - Implementor to register

putCloneMethod

public void putCloneMethod(Class<?> clazz,
                           MethodHandle handle)

Description copied from interface: CloneDriver

Put the clone() method for the indicated class

Specified by:

putCloneMethod in interface CloneDriver

Parameters:

clazz - The class to obtain the method for

handle - The related MethodHandle

getBuiltInImplementor

public CloneImplementor getBuiltInImplementor(Class<?> clazz)

Description copied from interface: CloneDriver

Gets the built in implementor for the given class

Specified by:

getBuiltInImplementor in interface CloneDriver

Parameters:

clazz - The class

Returns:

A CloneImplementor

isImmutableInstance

public boolean isImmutableInstance(Object instance)

Description copied from interface: CloneDriver

Indicates whether the given object instance should be treated as immutable

Specified by:

isImmutableInstance in interface CloneDriver

Parameters:

instance - The instance to check for whether it is registered as immutable

Returns:

True if the object is registered as immutable

putImmutableInstance

public void putImmutableInstance(Object instance)

Description copied from interface: CloneDriver

Stores an object instance to be treated as immutable

Specified by:

putImmutableInstance in interface CloneDriver

Parameters:

instance - Object to be considered immutable

isTrackReferences

public boolean isTrackReferences()

Description copied from interface: CloneDriver

Indicates whether to track references

Specified by:

isTrackReferences in interface CloneDriver

Returns:

trackReferences Default is true

isTrackReferencesForFlatClasses

public boolean isTrackReferencesForFlatClasses()

Description copied from interface: CloneDriver

Indicates whether to also track references for flat classes when tracking references.

Specified by:

isTrackReferencesForFlatClasses in interface CloneDriver

Returns:

trackReferences Default is false