Package org.apache.avalon.framework

Class ValuedEnum

java.lang.Object
org.apache.avalon.framework.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.

Version:
CVS $Revision: 1.21 $ $Date: 2004/02/11 14:34:24 $
Author:
Avalon Development Team

  • Constructor Details

    • ValuedEnum

      protected ValuedEnum(String name, int value)
      Constructor for enum item.

      Note: access changed from public to protected after 4.0. See class description.

      Parameters:
      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.

      Parameters:
      name - the name of enum item.
      value - the value of enum item.
      map - the Map to add enum item to.

  • Method Details

    • getValue

      public final int getValue()
      Get value of enum item.
      Returns:
      the enum item's value.

    • isEqualTo

      public final boolean isEqualTo(ValuedEnum other)
      Test if enum item is equal in value to other enum.
      Parameters:
      other - the other enum
      Returns:
      true if equal

    • isGreaterThan

      public final boolean isGreaterThan(ValuedEnum other)
      Test if enum item is greater than in value to other enum.
      Parameters:
      other - the other enum
      Returns:
      true if greater than

    • isGreaterThanOrEqual

      public final boolean isGreaterThanOrEqual(ValuedEnum other)
      Test if enum item is greater than or equal in value to other enum.
      Parameters:
      other - the other enum
      Returns:
      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.
      Parameters:
      other - the other enum
      Returns:
      true if less than

    • isLessThanOrEqual

      public final boolean isLessThanOrEqual(ValuedEnum other)
      Test if enum item is less than or equal in value to other enum.
      Parameters:
      other - the other enum
      Returns:
      true if less than or equal

    • toString

      public String toString()
      Override toString method to produce human readable description.
      Overrides:
      toString in class Enum
      Returns:
      String in the form type[name=value], eg.: JavaVersion[Java 1.0=100].