com.db4o.reflect.generic

Class GenericReflector

java.lang.Object

com.db4o.reflect.generic.GenericReflector

All Implemented Interfaces:

DeepClone, Reflector

public class GenericReflector
extends java.lang.Object
implements Reflector, DeepClone

db4o provides GenericReflector as a wrapper around specific reflector (delegate). GenericReflector is set when an ObjectContainer is opened. All subsequent reflector calls are routed through this interface.

An instance of GenericReflector can be obtained through ExtObjectContainer.reflector().

GenericReflector keeps list of known classes in memory. When the GenericReflector is called, it first checks its list of known classes. If the class cannot be found, the task is transferred to the delegate reflector. If the delegate fails as well, generic objects are created, which hold simulated "field values" in an array of objects.

Generic reflector makes possible the following usecases:

• running a db4o server without deploying application classes;
• running db4o on Java dialects without reflection (J2ME CLDC, MIDP);
• easier access to stored objects where classes or fields are not available;
• running refactorings in the reflector;
• building interfaces to db4o from any programming language.

One of the live usecases is ObjectManager, which uses GenericReflector to read C# objects from Java.

Constructor Summary

Constructors

Constructor and Description
GenericReflector(Reflector delegateReflector)
GenericReflector(Transaction trans, Reflector delegateReflector) Creates an instance of GenericReflector

Method Summary

Methods

Modifier and Type	Method and Description
ReflectArray	array() returns an ReflectArray object, the equivalent to java.lang.reflect.Array.
void	configuration(ReflectorConfiguration config)
java.lang.Object	deepClone(java.lang.Object obj) Creates a clone of provided object
ReflectClass	forClass(java.lang.Class clazz) Returns a ReflectClass instance for the specified class
ReflectClass	forName(java.lang.String className) Returns a ReflectClass instance for the specified class name
ReflectClass	forObject(java.lang.Object obj) Returns a ReflectClass instance for the specified class object
Reflector	getDelegate() Returns delegate reflector
boolean	hasTransaction() If there is a transaction assosiated with the current refector.
boolean	isCollection(ReflectClass candidate) Determines if a candidate ReflectClass is a collection
ReflectClass[]	knownClasses() Returns an array of classes known to the reflector
void	register(GenericClass clazz) Register a class
void	registerCollection(java.lang.Class clazz) Register a class as a collection
void	registerCollection(ReflectClassPredicate predicate) Register a predicate as a collection
void	registerPrimitiveClass(int id, java.lang.String name, GenericConverter converter) Registers primitive class
void	setParent(Reflector reflector) method stub: generic reflector does not have a parent
void	setTransaction(Transaction trans) Associated a transaction with the current reflector.

Methods inherited from class java.lang.Object

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

Constructor Detail

GenericReflector

public GenericReflector(Transaction trans,
                Reflector delegateReflector)

Creates an instance of GenericReflector

Parameters:

trans - transaction

delegateReflector - delegate reflector, providing specific reflector functionality. For example

GenericReflector

public GenericReflector(Reflector delegateReflector)

Method Detail

deepClone

public java.lang.Object deepClone(java.lang.Object obj)

Creates a clone of provided object

Specified by:

deepClone in interface DeepClone

Parameters:

obj - object to copy

Returns:

copy of the submitted object

hasTransaction

public boolean hasTransaction()

If there is a transaction assosiated with the current refector.

Returns:

true if there is a transaction assosiated with the current refector.

setTransaction

public void setTransaction(Transaction trans)

Associated a transaction with the current reflector.

Parameters:

trans -

array

public ReflectArray array()

Description copied from interface: Reflector

returns an ReflectArray object, the equivalent to java.lang.reflect.Array.

Specified by:

array in interface Reflector

Returns:

generic reflect array instance.

forClass

public ReflectClass forClass(java.lang.Class clazz)

Returns a ReflectClass instance for the specified class

Specified by:

forClass in interface Reflector

Parameters:

clazz - class

Returns:

a ReflectClass instance for the specified class

See Also:

ReflectClass

forName

public ReflectClass forName(java.lang.String className)

Returns a ReflectClass instance for the specified class name

Specified by:

forName in interface Reflector

Parameters:

className - class name

Returns:

a ReflectClass instance for the specified class name

See Also:

ReflectClass

forObject

public ReflectClass forObject(java.lang.Object obj)

Returns a ReflectClass instance for the specified class object

Specified by:

forObject in interface Reflector

Parameters:

obj - class object

Returns:

a ReflectClass instance for the specified class object

See Also:

ReflectClass

getDelegate

public Reflector getDelegate()

Returns delegate reflector

Returns:

delegate reflector

isCollection

public boolean isCollection(ReflectClass candidate)

Determines if a candidate ReflectClass is a collection

Specified by:

isCollection in interface Reflector

Parameters:

candidate - candidate ReflectClass

Returns:

true if a candidate ReflectClass is a collection.

registerCollection

public void registerCollection(java.lang.Class clazz)

Register a class as a collection

Parameters:

clazz - class to be registered

registerCollection

public void registerCollection(ReflectClassPredicate predicate)

Register a predicate as a collection

Parameters:

predicate - predicate to be registered

register

public void register(GenericClass clazz)

Register a class

Parameters:

clazz - class

knownClasses

public ReflectClass[] knownClasses()

Returns an array of classes known to the reflector

Returns:

an array of classes known to the reflector

registerPrimitiveClass

public void registerPrimitiveClass(int id,
                          java.lang.String name,
                          GenericConverter converter)

Registers primitive class

Parameters:

id - class id

name - class name

converter - class converter

setParent

public void setParent(Reflector reflector)

method stub: generic reflector does not have a parent

Specified by:

setParent in interface Reflector

configuration

public void configuration(ReflectorConfiguration config)

Specified by:

configuration in interface Reflector