org.apache.velocity.app

Class FieldMethodizer

public class FieldMethodizer extends Object

This is a small utility class allow easy access to static fields in a class, such as string constants. Velocity will not introspect for class fields (and won't in the future :), but writing setter/getter methods to do this really is a pain, so use this if you really have to access fields.

The idea it so enable access to the fields just like you would in Java. For example, in Java, you would access a static field like

  MyClass.STRING_CONSTANT
  
and that is the same thing we are trying to allow here.

So to use in your Java code, do something like this :

   context.put("runtime", new FieldMethodizer( "org.apache.velocity.runtime.Runtime" ));
  
and then in your template, you can access any of your static fields in this way :
  
   $runtime.RUNTIME_LOG_WARN_STACKTRACE
  

Right now, this class only methodizes public static fields. It seems that anything else is too dangerous. This class is for convenience accessing 'constants'. If you have fields that aren't static it may be better to handle them by explicitly placing them into the context.

Version: $Id: FieldMethodizer.java,v 1.3.14.1 2004/03/03 23:22:53 geirm Exp $

Author: Geir Magnusson Jr.

Field Summary
HashMapclassHash
Hold the class objects by field name
HashMapfieldHash
Hold the field objects by field name
Constructor Summary
FieldMethodizer()
Allow object to be initialized without any data.
FieldMethodizer(String s)
Constructor that takes as it's arg the name of the class to methodize.
FieldMethodizer(Object o)
Constructor that takes as it's arg a living object to methodize.
Method Summary
voidaddObject(String s)
Add the Name of the class to methodize
voidaddObject(Object o)
Add an Object to methodize
Objectget(String fieldName)
Accessor method to get the fields by name.
voidinspect(Class clas)
Method that retrieves all public static fields in the class we are methodizing.

Field Detail

classHash

private HashMap classHash
Hold the class objects by field name

fieldHash

private HashMap fieldHash
Hold the field objects by field name

Constructor Detail

FieldMethodizer

public FieldMethodizer()
Allow object to be initialized without any data. You would use addObject() to add data later.

FieldMethodizer

public FieldMethodizer(String s)
Constructor that takes as it's arg the name of the class to methodize.

Parameters: s Name of class to methodize.

FieldMethodizer

public FieldMethodizer(Object o)
Constructor that takes as it's arg a living object to methodize. Note that it will still only methodized the public static fields of the class.

Parameters: s Name of class to methodize.

Method Detail

addObject

public void addObject(String s)
Add the Name of the class to methodize

addObject

public void addObject(Object o)
Add an Object to methodize

get

public Object get(String fieldName)
Accessor method to get the fields by name.

Parameters: fieldName Name of static field to retrieve

Returns: The value of the given field.

inspect

private void inspect(Class clas)
Method that retrieves all public static fields in the class we are methodizing.
Copyright B) 2002 Apache Software Foundation. All Rights Reserved.