org.apache.avalon.framework
Class ValuedEnum
Enum
org.apache.avalon.framework.ValuedEnum
public abstract class ValuedEnum
extends Enum
Basic enum class for type-safe enums with values. Valued enum items can be compared and ordered
with the provided methods. Should be used as an abstract base. For example:
import org.apache.avalon.framework.ValuedEnum;
public final class JavaVersion
extends ValuedEnum
{
//standard enums for version of JVM
public static final JavaVersion JAVA1_0 = new JavaVersion( "Java 1.0", 100 );
public static final JavaVersion JAVA1_1 = new JavaVersion( "Java 1.1", 110 );
public static final JavaVersion JAVA1_2 = new JavaVersion( "Java 1.2", 120 );
public static final JavaVersion JAVA1_3 = new JavaVersion( "Java 1.3", 130 );
private JavaVersion( final String name, final int value )
{
super( name, value );
}
}
The above class could then be used as follows:
import org.apache.avalon.framework.context.Context;
import org.apache.avalon.framework.context.Contextualizable;
import org.apache.avalon.framework.context.ContextException;
public class MyComponent implements Contextualizable
{
JavaVersion requiredVer = JavaVersion.JAVA1_2;
public void contextualize(Context context)
throws ContextException
{
JavaVersion ver = (JavaVersion)context.get("java.version");
if ( ver.isLessThan( requiredVer ) )
{
throw new RuntimeException( requiredVer.getName()+" or higher required" );
}
}
}
As with
Enum
, the
ValuedEnum(String,int,Map)
constructor can be used to
populate a
Map
, from which further functionality can be derived.
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: 1.21 $ $Date: 2004/02/11 14:34:24 $ValuedEnum(String name, int value) - Constructor for enum item.
|
ValuedEnum(String name, int value, Map map) - Constructor for enum item so that it gets added to Map at creation.
|
int | getValue() - Get value of enum item.
|
boolean | isEqualTo(ValuedEnum other) - Test if enum item is equal in value to other enum.
|
boolean | isGreaterThan(ValuedEnum other) - Test if enum item is greater than in value to other enum.
|
boolean | isGreaterThanOrEqual(ValuedEnum other) - Test if enum item is greater than or equal in value to other enum.
|
boolean | isLessThan(ValuedEnum other) - Test if enum item is less than in value to other enum.
|
boolean | isLessThanOrEqual(ValuedEnum other) - Test if enum item is less than or equal in value to other enum.
|
String | toString() - Override toString method to produce human readable description.
|
ValuedEnum
protected ValuedEnum(String name,
int value)
Constructor for enum item.
Note: access changed from
public
to
protected
after 4.0. See class description.
name
- the name of enum item.value
- the value of enum item.
ValuedEnum
protected ValuedEnum(String name,
int value,
Map map)
Constructor for enum item so that it gets added to Map at creation.
Adding to a map is useful for implementing find...() style methods.
Note: access changed from public
to
protected
after 4.0. See class description.
name
- the name of enum item.value
- the value of enum item.map
- the Map
to add enum item to.
getValue
public final int getValue()
Get value of enum item.
isEqualTo
public final boolean isEqualTo(ValuedEnum other)
Test if enum item is equal in value to other enum.
isGreaterThan
public final boolean isGreaterThan(ValuedEnum other)
Test if enum item is greater than in value to other enum.
isGreaterThanOrEqual
public final boolean isGreaterThanOrEqual(ValuedEnum other)
Test if enum item is greater than or equal in value to other enum.
- true if greater than or equal
isLessThan
public final boolean isLessThan(ValuedEnum other)
Test if enum item is less than in value to other enum.
isLessThanOrEqual
public final boolean isLessThanOrEqual(ValuedEnum other)
Test if enum item is less than or equal in value to other enum.
- true if less than or equal
toString
public String toString()
Override toString method to produce human readable description.
- String in the form
type[name=value]
, eg.:
JavaVersion[Java 1.0=100]
.