org.datanucleus.identity

Class ObjectId

java.lang.Object

org.datanucleus.identity.SingleFieldId

org.datanucleus.identity.ObjectId

All Implemented Interfaces:

Externalizable, Serializable, Comparable

public class ObjectId
extends SingleFieldId

This class is for identity with a single Object type field.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	ObjectId.StringConstructor Construct an instance of a key class using a String as input.

Field Summary

Fields inherited from class org.datanucleus.identity.SingleFieldId

hashCode, STRING_DELIMITER, targetClassName

Constructor Summary

Constructors

Constructor and Description
ObjectId()
ObjectId(Class pcClass, Object param) Constructor with class and key.

Method Summary

Modifier and Type	Method and Description
int	compareTo(Object o)
static Object	construct(String className, String keyString) Construct an instance of the parameter class, using the keyString as an argument to the constructor.
Object	getKey()
Object	getKeyAsObject()
protected boolean	keyEquals(SingleFieldId obj)
void	readExternal(ObjectInput in) Read this object.
static Object	registerStringConstructor(Class cls, ObjectId.StringConstructor sc) Register special StringConstructor instances.
String	toString() Return the String form of the object id.
void	writeExternal(ObjectOutput out) Write this object.

Methods inherited from class org.datanucleus.identity.SingleFieldId

assertKeyNotNull, compare, equals, getTargetClassName, hashCode

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

ObjectId

public ObjectId(Class pcClass,
                Object param)

Constructor with class and key.

Parameters:

pcClass - the class

param - the key

ObjectId

public ObjectId()

Method Detail

getKey

public Object getKey()

getKeyAsObject

public Object getKeyAsObject()

Specified by:

getKeyAsObject in class SingleFieldId

toString

public String toString()

Return the String form of the object id. The class of the object id is written as the first part of the result so that the class can be reconstructed later. Then the toString of the key instance is appended. During construction, this process is reversed. The class is extracted from the first part of the String, and the String constructor of the key is used to construct the key itself.

Overrides:

toString in class Object

Returns:

the String form of the key

keyEquals

protected boolean keyEquals(SingleFieldId obj)

Specified by:

keyEquals in class SingleFieldId

compareTo

public int compareTo(Object o)

writeExternal

public void writeExternal(ObjectOutput out)
                   throws IOException

Write this object. Write the superclass first.

Specified by:

writeExternal in interface Externalizable

Overrides:

writeExternal in class SingleFieldId

Parameters:

out - the output

Throws:

IOException

readExternal

public void readExternal(ObjectInput in)
                  throws IOException,
                         ClassNotFoundException

Read this object. Read the superclass first.

Specified by:

readExternal in interface Externalizable

Overrides:

readExternal in class SingleFieldId

Parameters:

in - the input

Throws:

IOException

ClassNotFoundException

registerStringConstructor

public static Object registerStringConstructor(Class cls,
                                               ObjectId.StringConstructor sc)

Register special StringConstructor instances. These instances are for constructing instances from String parameters where there is no String constructor for them.

Parameters:

cls - the class to register a StringConstructor for

sc - the StringConstructor instance

Returns:

the previous StringConstructor registered for this class

construct

public static Object construct(String className,
                               String keyString)

Construct an instance of the parameter class, using the keyString as an argument to the constructor. If the class has a StringConstructor instance registered, use it. If not, try to find a constructor for the class with a single String argument. Otherwise, throw a NucleusUserException. TODO Consider moving this to ObjectId or IdentityManager

Parameters:

className - the name of the class

keyString - the String parameter for the constructor

Returns:

the result of construction