blackboard.persist
Class UnsetId

java.lang.Object
  blackboard.persist.Id
      blackboard.persist.UnsetId

All Implemented Interfaces:

java.lang.Comparable

public class UnsetId
extends Id

The UnsetId class represents an unset data object Id.

Since:

Bb 5.5

Version:

$Revision: #1 $ $Date: 2005/06/27 $

Field Summary

static java.lang.String

TO_STR

Fields inherited from class blackboard.persist.Id

UNSET_ID

Constructor Summary

UnsetId()
Default constructor

Method Summary

int	compareTo(java.lang.Object obj) The sole method of the Comparable interface.
boolean	equals(java.lang.Object obj) Overrides the equals() method in Object to provide a simple way to compare two UnsetId s.
int	hashCode() Returns a hash code value for the object.
boolean	isSet() Determines if this UnsetId has been set.
void	setContainer(Container container) Override Id.setContainer(Container) to prevent the setting of the container value within an UnsetId.
void	setDataType(DataType dataType) Override Id.setDataType(DataType) to prevent the setting of the data type value within an UnsetId.
java.lang.String	toExternalString() Converts this UnsetId into its String representation.
java.lang.String	toString() Converts this UnsetId into its String representation.

Methods inherited from class blackboard.persist.Id

assertIsSet, assertMatchesContainer, assertMatchesDataType, generateId, generateId, generateId, getContainer, getDataType, hasSameContainer, hasSameDataType, load, matchesContainer, matchesDataType, newId

Methods inherited from class java.lang.Object

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

Field Detail

TO_STR

public static final java.lang.String TO_STR

See Also:

Constant Field Values

Constructor Detail

UnsetId

public UnsetId()

Default constructor

Method Detail

isSet

public boolean isSet()

Determines if this UnsetId has been set.

Specified by:

isSet in class Id

Returns:

false -- an unset id instance is always not set (thus the "unset" in UnsetId)

equals

public boolean equals(java.lang.Object obj)

Overrides the equals() method in Object to provide a simple way to compare two UnsetId s.

Specified by:

equals in class Id

Parameters:

obj - the object to be compared.

Returns:

true if the provided input is an UnsetId -- two UnsetIds are always equal.

compareTo

public int compareTo(java.lang.Object obj)
              throws java.lang.ClassCastException

The sole method of the Comparable interface. Used for sorting and natural-ordering algorithms.

Specified by:

compareTo in interface java.lang.Comparable

Specified by:

compareTo in class Id

Parameters:

obj - the object to be compared to.

Returns:

zero if the provided input is an UnsetId -- two UnsetIds are always equal.

Throws:

java.lang.ClassCastException - thrown if the specified object's type prevents it from being compared to this Object

hashCode

public int hashCode()

Returns a hash code value for the object. This method is supported for the benefit of hashtables such as those provided by java.util.Hashtable

Specified by:

hashCode in class Id

Returns:

a hash code value for this object as an int. All UnsetId instances are equal and therefore always return the same hash value.

toExternalString

public java.lang.String toExternalString()

Converts this UnsetId into its String representation.

Specified by:

toExternalString in class Id

Returns:

A String representation of this UnsetId.

See Also:

Id.toString(), BbPersistenceManager.generateId(DataType,String), Container.generateId(DataType,String)

toString

public java.lang.String toString()

Converts this UnsetId into its String representation.

Specified by:

toString in class Id

Returns:

A String representation of this UnsetId.

See Also:

Id.toExternalString()

setContainer

public void setContainer(Container container)

Override Id.setContainer(Container) to prevent the setting of the container value within an UnsetId. An UnsetId is never associated with a container and therefore the container value of an UnsetId is always null.

Overrides:

setContainer in class Id

Parameters:

container - the Container to associate with this id. Can not be null.

Throws:

RunTimeException - always thrown if called

setDataType

public void setDataType(DataType dataType)

Override Id.setDataType(DataType) to prevent the setting of the data type value within an UnsetId. An UnsetId is has a hard-coded "null" data type that can not be changed.

Overrides:

setDataType in class Id

Parameters:

dataType - the DataType to associate with this Id. Can not be null. If no data type is presently desired pass in DataType.NULL_DATA_TYPE.

Throws:

RunTimeException - always thrown if called

See Also:

DataType.NULL_DATA_TYPE