Module org.datanucleus

Package org.datanucleus.identity

Class SingleFieldId<T>

java.lang.Object

org.datanucleus.identity.SingleFieldId<T>

All Implemented Interfaces:

Externalizable, Serializable, Comparable

Direct Known Subclasses:

ByteId, CharId, IntId, LongId, ObjectId, ShortId, StringId

public abstract class SingleFieldId<T>
extends Object
implements Externalizable, Comparable

This class is the abstract base class for all single field identity classes. TODO All subclasses should implement the same rules as applies to all identity classes, namely String constructor taking output of toString(), etc.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
protected int	hashCode
protected static String	STRING_DELIMITER
protected String	targetClassName	The name of the class of the target persistable object.

Constructor Summary

Constructors

Modifier	Constructor	Description
	SingleFieldId()
protected	SingleFieldId(Class pcClass)

Method Summary

Modifier and Type	Method	Description
protected void	assertKeyNotNull(Object key)	Assert that the key is not null.
protected int	compare(SingleFieldId o)	Determine the ordering of identity objects.
boolean	equals(Object obj)	Check the class and class name and object type.
abstract T	getKeyAsObject()
String	getTargetClassName()
int	hashCode()
protected abstract boolean	keyEquals(SingleFieldId other)
void	readExternal(ObjectInput in)	Read from the input stream.
void	writeExternal(ObjectOutput out)	Write to the output stream.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Comparable

compareTo

Field Detail

STRING_DELIMITER

protected static final String STRING_DELIMITER

See Also:

Constant Field Values

targetClassName

protected String targetClassName

The name of the class of the target persistable object.

hashCode

protected int hashCode

Constructor Detail

SingleFieldId

protected SingleFieldId(Class pcClass)

SingleFieldId

public SingleFieldId()

Method Detail

assertKeyNotNull

protected void assertKeyNotNull(Object key)

Assert that the key is not null. Throw a NucleusUserException if the given key is null.

Parameters:

key - The key

getTargetClassName

public String getTargetClassName()

getKeyAsObject

public abstract T getKeyAsObject()

equals

public boolean equals(Object obj)

Check the class and class name and object type.

Overrides:

equals in class Object

Parameters:

obj - the other object

Returns:

true if the class name is the same

keyEquals

protected abstract boolean keyEquals(SingleFieldId other)

hashCode

public int hashCode()

Overrides:

hashCode in class Object

writeExternal

public void writeExternal(ObjectOutput out)
                   throws IOException

Write to the output stream.

Specified by:

writeExternal in interface Externalizable

Parameters:

out - the stream

Throws:

IOException

readExternal

public void readExternal(ObjectInput in)
                  throws IOException,
                         ClassNotFoundException

Read from the input stream. Creates a new instance with the target class name set

Specified by:

readExternal in interface Externalizable

Parameters:

in - Input object

Throws:

IOException

ClassNotFoundException

compare

protected int compare(SingleFieldId o)

Determine the ordering of identity objects. Only the class name is compared. This method is only used by subclasses.

Parameters:

o - Other identity

Returns:

The relative ordering between the objects