org.sape.carbon.core.util.enum
Class BaseEnum

java.lang.Object
  |
  +--org.sape.carbon.core.util.enum.BaseEnum

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

BootStrapperStateEnum, DayOfWeekEnum, LifecycleStateEnum, MailContentTypeEnum, MBeanOperationImpactEnum, MonthEnum, OperationsImpactEnum, QueueFullPolicyEnum, ResultSetConcurrencyEnum, ResultSetTypeEnum, SeverityEnum, TaskStatusEnum

public abstract class BaseEnum

extends Object

implements Serializable

This class acts as the base enumeration for all enumerated types in the system. It provides a simple and convenient mechanism to create new sets of enumeration instances and access them via ordinal or name based lookup.

This class also provides for the system wide storage of these objects, via static reference, so that all instances of a particular value of an enumerated type will in fact be the same instance. This has the advantage of allowing reference equals ("==") operations to work for instance comparison providing for very fast checks.

This base implementation will return null from most methods if unable to return the requested information. Subclasses are expected to check for these nulls and throw an appropriate subclass of EnumNotFoundException. Copyright 2002 Sapient

Since:

carbon 1.0

Version:

$Revision: 1.18 $($Author: dvoet $ / $Date: 2003/05/05 21:21:22 $)

Author:

Greg Hinkle, January 2002

See Also:

Serialized Form

Nested Class Summary

private static class

BaseEnum.EnumTypeAggregator This inner class of the BaseEnum system catalogs all enumeration instances for one particular class of enumerated values.

Field Summary

private static Map	enumTypeMap A static cache of the enum types currently loaded in the system.
protected String	name The string representation of this enumeration instance
protected int	ordinal The ordinal representation of this enumeration instance

Constructor Summary

protected	BaseEnum(Class enumeratedType, String name) Constructs a new instance of the specific enumerated type automatically selecting the next ordinal value for it and placing references to it into the main catalogue for this type.
protected	BaseEnum(Class enumeratedType, String name, int ordinal) Constructs a new instance of the specific enumerated type with the specified name and ordinal values.

Method Summary

boolean	equals(Object that) This implementation of equals does instance reference comparisons since all instances of single type actually are the same object.
static BaseEnum	getByName(String name, Class enumeratedType) Static accessor to the specified enumerated type value.
static BaseEnum	getByOrdinal(int ordinal, Class enumeratedType) Static accessor to the specified enumerated type value.
private static BaseEnum.EnumTypeAggregator	getEnumTypeAggregator(Class enumeratedType) Gets the EnumTypeAggregator for the given enumeratedType
String	getName() Accesses the name of this enumeration instance
int	getOrdinal() Accesses the ordinal represenation of this enumeration instance
int	hashCode() This implementation of hashCode provides the system hashCode (location in memory) since all instances of single type actually are the same object.
static Iterator	iterator(Class enumeratedType) Static accessor to an iterator for all instances of a specific enumeration type.
String	toString() Returns a string representation of this enumeration instance that includes its true class type, its enumeration name and its ordinal value.

Methods inherited from class java.lang.Object

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

Field Detail

name

protected String name

The string representation of this enumeration instance

ordinal

protected int ordinal

The ordinal representation of this enumeration instance

enumTypeMap

private static Map enumTypeMap

A static cache of the enum types currently loaded in the system.

Constructor Detail

BaseEnum

protected BaseEnum(Class enumeratedType,
                   String name)

Constructs a new instance of the specific enumerated type automatically selecting the next ordinal value for it and placing references to it into the main catalogue for this type.

Note: Never mix the usage of the two constructors of this class in subclasses. This can lead to improperly numbered enumerations.

Parameters:

enumeratedType - the class type to build

name - the name or system wide string key to the enum instance

BaseEnum

protected BaseEnum(Class enumeratedType,
                   String name,
                   int ordinal)

Constructs a new instance of the specific enumerated type with the specified name and ordinal values. Use this constructor for explicit control over the ordinal values of enumeration instances.

Note: Never mix the usage of the two constructors of this class in subclasses. This can lead to improperly numbered enumerations.

Parameters:

enumeratedType - the subclass of BaseEnum to create an enumeration instance of

name - the String representation (name) of this type

ordinal - the ordinal value reperesentation of this type

Method Detail

getName

public String getName()

Accesses the name of this enumeration instance

Returns:

String the name of this enumeration

getOrdinal

public int getOrdinal()

Accesses the ordinal represenation of this enumeration instance

Returns:

long the ordinal value of this enumeration

toString

public String toString()

Returns a string representation of this enumeration instance that includes its true class type, its enumeration name and its ordinal value.

Overrides:

toString in class Object

Returns:

a String representation of this value

equals

public final boolean equals(Object that)

This implementation of equals does instance reference comparisons since all instances of single type actually are the same object. This method can not, and should not, be overriden.

Overrides:

equals in class Object

Parameters:

that - the enum object to compare against

Returns:

true if they are the same object, false otherwise

hashCode

public final int hashCode()

This implementation of hashCode provides the system hashCode (location in memory) since all instances of single type actually are the same object. This method can not, and should not, be overriden.

Overrides:

hashCode in class Object

Returns:

a system hashcode of the object

getByName

public static final BaseEnum getByName(String name,
                                       Class enumeratedType)

Static accessor to the specified enumerated type value. Will return a specific instance of that enumerated type by its name.

Parameters:

name - the name of the enumeration instance to return

enumeratedType - a subclass of BaseEnum which is the type of the instance to return

Returns:

the BaseEnum subclass that corresponds to this type and name

getByOrdinal

public static final BaseEnum getByOrdinal(int ordinal,
                                          Class enumeratedType)

Static accessor to the specified enumerated type value. Will return a specific instance of that enumerated type by its name.

Parameters:

ordinal - the ordinal value of this

enumeratedType - a subclass of BaseEnum which is the type of the instance to return

Returns:

the BaseEnum subclass that corresponds to this type and ordinal

iterator

public static final Iterator iterator(Class enumeratedType)

Static accessor to an iterator for all instances of a specific enumeration type. This iterator is ordered by the ordinal value of the enumeration instances.

Parameters:

enumeratedType - a subclass of BaseEnum which is the type of the instance to return

Returns:

Iterator an iterator over the values of this enumerated type

getEnumTypeAggregator

private static BaseEnum.EnumTypeAggregator getEnumTypeAggregator(Class enumeratedType)

Gets the EnumTypeAggregator for the given enumeratedType

Since:

carbon 1.2