org.codehaus.janino.util.enumerator
Class Enumerator

java.lang.Object
  extended by org.codehaus.janino.util.enumerator.Enumerator
Direct Known Subclasses:
Access, Parser.ClassDeclarationContext, Parser.InterfaceDeclarationContext

public abstract class Enumerator
extends java.lang.Object

A class that represents an enumerated value. Its main features are its toString() and fromString(String, Class) method, which map names to values and vice versa.

To use this class, derive from it and define one or more public static final fields, as follows:

 public final class Suit extends Enumerator {

     // Exactly N instances of "Suit" exist to represent the N possible values.
     public static final Suit CLUBS    = new Suit("clubs");
     public static final Suit DIAMONDS = new Suit("diamonds");
     public static final Suit HEARTS   = new Suit("hearts");
     public static final Suit SPADES   = new Suit("spades");

     // Optional, if you want to use EumeratorSet arithmetics.
     public static final EnumeratorSet NONE = new EnumeratorSet(Suit.class      ).setName("none");
     public static final EnumeratorSet ALL  = new EnumeratorSet(Suit.class, true).setName("all");

     // These MUST be declared exactly like this:
     private Suit(String name) { super(name); }
     public static Suit fromString(String name) throws EnumeratorFormatException {
         return (Suit) Enumerator.fromString(name, Suit.class);
     }
 }
 

See Also:
Effective Java, Item 21

Constructor Summary
protected Enumerator(java.lang.String name)
          Initialize the enumerator to the given value.
 
Method Summary
 boolean equals(java.lang.Object that)
          Equality is reference identity.
protected static Enumerator fromString(java.lang.String name, java.lang.Class enumeratorClass)
          Initialize an Enumerator from a string.
 int hashCode()
          Enforce Object's notion of Object.hashCode().
 java.lang.String toString()
          Returns the name passed to Enumerator(String).
 
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
 

Constructor Detail

Enumerator

protected Enumerator(java.lang.String name)
Initialize the enumerator to the given value.

Method Detail

equals

public final boolean equals(java.lang.Object that)
Equality is reference identity.

Overrides:
equals in class java.lang.Object

hashCode

public final int hashCode()
Enforce Object's notion of Object.hashCode().

Overrides:
hashCode in class java.lang.Object

fromString

protected static final Enumerator fromString(java.lang.String name,
                                             java.lang.Class enumeratorClass)
                                      throws EnumeratorFormatException
Initialize an Enumerator from a string.

The given string is converted into a value by looking at all instances of the given type created so far.

Derived classes should invoke this method as follows:

 public class Suit extends Enumerator {
     ...
     public static Suit fromString(String name) throws EnumeratorFormatException {
         return (Suit) Enumerator.fromString(name, Suit.class);
     }
 }

Throws:
EnumeratorFormatException - if the string cannot be identified

toString

public java.lang.String toString()
Returns the name passed to Enumerator(String).

Overrides:
toString in class java.lang.Object


Copyright © 2001-2011. All Rights Reserved.