com.webobjects.foundation
Class NSValidation.DefaultImplementation

java.lang.Object
  |
  +--com.webobjects.foundation.NSValidation.DefaultImplementation

Enclosing class:

NSValidation

public static class NSValidation.DefaultImplementation

extends Object

The methods in the NSValidation.DefaultImplementation class are just like the methods defined by the NSValidation interface, except they are static methods and they take an additional argument, which is the object on which the default implementation should operate.

For example, suppose an Employee class implements NSValidation using NSValidation.DefaultImplementation. Employee's validateValueForKey method would then look like this:

 public Object validateValueForKey(Object value,String key){
   return
   NSValidation.DefaultImplementation.validateValueForKey(this,value,key)}
 

The NSValidation.DefaultImplementation methods search for property-specific methods of the form validateKey and invoke them if they exist. Thus an NSValidation class should implement a validate method for each property that has associated validation logic. For example, a validateAge method could check that the value a user enters as an age is within acceptable limits and throw an NSValidation.ValidationException if it finds an unacceptable value.

Because custom validation logic was implemented in the validateKey methods, implementing it from scratch in NSValidation methods is rarely needed. Rather, the default implementation provided by NSValidation.DefaultImplementation is generally sufficient.

Note: Always use the default implementation of NSValidation provided by the foundation package. The default implementations have significant performance optimizations. To benefit from them, implement NSValidation on a custom class as shown above by using the methods in NSValidation.DefaultImplementation or, if your class inherits from an WebObjects class that implements NSValidation, don't override the inherited implementation. Using a custom implementation incurs significant performance penalties.

See Also:

NSValidation.validateValueForKey(java.lang.Object, java.lang.String), NSValidation.validateTakeValueForKeyPath(java.lang.Object, java.lang.String)

Method Summary

static Object	validateTakeValueForKeyPath(Object object, Object value, String keyPath) Confirms that value is legal for an objects's property, which is named by keyPath, and assigns the value to the property if it's legal (and if value is different from the current value).
static Object	validateValueForKey(Object object, Object value, String key) Confirms that value is legal for the NSValidation's property, which is named by key, and returns the validated value if it's legal, or throws an NSValidation.ValidationException if it isn't.

Methods inherited from class java.lang.Object

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

Method Detail

validateTakeValueForKeyPath

public static Object validateTakeValueForKeyPath(Object object,
                                                 Object value,
                                                 String keyPath)
                                          throws NSValidation.ValidationException

Confirms that value is legal for an objects's property, which is named by keyPath, and assigns the value to the property if it's legal (and if value is different from the current value).

Parameters:

object - object on the destination showed by the keypath

value - value corresponding to the keypath

keyPath - relative path of the method

Returns:

NSValidation implementor with the new value assigned to it

Throws:

NSValidation.ValidationException - value isn't legal to NSValidation

See Also:

NSValidation.validateTakeValueForKeyPath(java.lang.Object, java.lang.String)

validateValueForKey

public static Object validateValueForKey(Object object,
                                         Object value,
                                         String key)
                                  throws NSValidation.ValidationException

Confirms that value is legal for the NSValidation's property, which is named by key, and returns the validated value if it's legal, or throws an NSValidation.ValidationException if it isn't.

Parameters:

object - object on the destination showed by the keypath

value - value corresponding to the keypath

key - property of object

Returns:

the new value for the NSValidation's implementor

Throws:

NSValidation.ValidationException - value isn't legal to NSValidation

See Also:

NSValidation.validateValueForKey(java.lang.Object, java.lang.String)