Package org.apache.velocity.app.event

Interface InvalidReferenceEventHandler

All Superinterfaces:
EventHandler
All Known Implementing Classes:
EventExample, ReportInvalidReferences
public interface InvalidReferenceEventHandler extends EventHandler
Event handler called when an invalid reference is encountered. Allows the application to report errors or substitute return values. May be chained in sequence; the behavior will differ per method.

This feature should be regarded as experimental.

Since:
1.5
Version:
$Id$
Author:
Will Glass-Husain

  • Method Details

    • invalidGetMethod

      Object invalidGetMethod(Context context, String reference, Object object, String property, Info info)
      Called when object is null or there is no getter for the given property. Also called for invalid references without properties. invalidGetMethod() will be called in sequence for each link in the chain until the first non-null value is returned.
      Parameters:
      context - the context when the reference was found invalid
      reference - string with complete invalid reference
      object - the object referred to, or null if not found
      property - the property name from the reference
      info - contains template, line, column details
      Returns:
      substitute return value for missing reference, or null if no substitute

    • invalidSetMethod

      boolean invalidSetMethod(Context context, String leftreference, String rightreference, Info info)
      Called when object is null or there is no setter for the given property. invalidSetMethod() will be called in sequence for each link in the chain until a true value is returned. It's recommended that false be returned as a default to allow for easy chaining.
      Parameters:
      context - the context when the reference was found invalid
      leftreference - left reference being assigned to
      rightreference - invalid reference on the right
      info - contains info on template, line, col
      Returns:
      if true then stop calling invalidSetMethod along the chain.

    • invalidMethod

      Object invalidMethod(Context context, String reference, Object object, String method, Info info)
      Called when object is null or the given method does not exist. invalidMethod() will be called in sequence for each link in the chain until the first non-null value is returned.
      Parameters:
      context - the context when the reference was found invalid
      reference - string with complete invalid reference
      object - the object referred to, or null if not found
      method - the name of the (non-existent) method
      info - contains template, line, column details
      Returns:
      substitute return value for missing reference, or null if no substitute