com.interface21.util
Class Constants

java.lang.Object
  |
  +--com.interface21.util.Constants

public class Constants

extends java.lang.Object

This class can be used to parse other classes containing constant definitions in public static final members. The asXXXX() methods of this class allow these constant values to be accessed via their string names.

Consider class Foo containing public final static int CONSTANT1 = 66; An instance of this class wrapping Foo.class will return the constant value of 66 from its asInt() method given the argument "CONSTANT1".

This class is ideal for use in PropertyEditors, enabling them to recognize the same names as the constants themselves, and freeing them from maintaining their own mapping.

TODO: add asBoolean, asDouble methods, keys method

Since:

16-Mar-2003

Version:

$Id: Constants.java,v 1.2 2003/06/25 18:12:18 jhoeller Exp $

Author:

Rod Johnson

Constructor Summary

Constants(java.lang.Class clazz)
Create a new Constants converter class wrapping the given class.

Method Summary

int	asInt(java.lang.String code) Return a constant value cast to an int
java.lang.Object	asObject(java.lang.String code) Parse the given string (upper or lower case accepted) and return the appropriate value if it's the name of a constant field in the class we're analysing.
java.lang.String	asString(java.lang.String code) Return a constant value as a String
int	getSize() Return the number of constants exposed

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Constants

public Constants(java.lang.Class clazz)

Create a new Constants converter class wrapping the given class. All public static final variables will be exposed, whatever their type.

Parameters:

clazz - class to analyze.

Method Detail

getSize

public int getSize()

Return the number of constants exposed

Returns:

int the number of constants exposed

asInt

public int asInt(java.lang.String code)
          throws ConstantException

Return a constant value cast to an int

Parameters:

code - name of the field

Returns:

int int value if successfuly

Throws:

ConstantException - if the field name wasn't found or if the type wasn't compatible with int

See Also:

asObject(java.lang.String)

asString

public java.lang.String asString(java.lang.String code)
                          throws ConstantException

Return a constant value as a String

Parameters:

code - name of the field

Returns:

String string value if successful. Works even if it's not a string (invokes toString()).

Throws:

ConstantException - if the field name wasn't found

See Also:

asObject(java.lang.String)

asObject

public java.lang.Object asObject(java.lang.String code)
                          throws ConstantException

Parse the given string (upper or lower case accepted) and return the appropriate value if it's the name of a constant field in the class we're analysing.

Throws:

ConstantException - if there's no such field