org.apache.avalon.framework
Class Enum
java.lang.Object
org.apache.avalon.framework.Enum
public abstract class Enum
extends java.lang.Object
Basic enum class for type-safe enums. Should be used as an abstract base. For example:
import org.apache.avalon.framework.Enum;
public final class Color extends Enum {
public static final Color RED = new Color( "Red" );
public static final Color GREEN = new Color( "Green" );
public static final Color BLUE = new Color( "Blue" );
private Color( final String color )
{
super( color );
}
}
If further operations, such as iterating over all items, are required, the
Enum(String,Map)
constructor can be used to populate a
Map
, from which
further functionality can be derived:
public final class Color extends Enum {
static final Map map = new HashMap();
public static final Color RED = new Color( "Red", map );
public static final Color GREEN = new Color( "Green", map );
public static final Color BLUE = new Color( "Blue", map );
private Color( final String color, final Map map )
{
super( color, map );
}
public static Iterator iterator()
{
return map.values().iterator();
}
}
NOTE: between 4.0 and 4.1, the constructors' access has been changed
from
public
to
protected
. This is to prevent users
of the Enum breaking type-safety by defining new Enum items. All Enum items
should be defined in the Enum class, as shown above.
CVS $Revision: 1.28 $ $Date: 2004/02/11 14:34:24 $Enum(String name) - Constructor to add a new named item.
|
Enum(String name, Map map) - Constructor to add a new named item.
|
boolean | equals(Object o) - Tests for equality.
|
String | getName() - Retrieve the name of this Enum item, set in the constructor.
|
int | hashCode()
|
String | toString() - Human readable description of this Enum item.
|
Enum
protected Enum(String name)
Constructor to add a new named item.
Note: access changed from
public
to
protected
after 4.0. See class description.
Enum
protected Enum(String name,
Map map)
Constructor to add a new named item.
Note: access changed from
public
to
protected
after 4.0. See class description.
name
- Name of the item.map
- A Map
, to which will be added a pointer to the newly constructed
object.
equals
public final boolean equals(Object o)
Tests for equality. Two Enum:s are considered equal
if they are of the same class and have the same names.
The method is also declared final - I (LSutic) did this to
allow the JIT to inline it easily.
getName
public final String getName()
Retrieve the name of this Enum item, set in the constructor.
- the name
String
of this Enum item
hashCode
public int hashCode()
toString
public String toString()
Human readable description of this Enum item. For use when debugging.
- String in the form
type[name]
, eg.:
Color[Red]
.