com.webobjects.foundation
Class NSKeyValueCoding.DefaultImplementation

java.lang.Object
  com.webobjects.foundation.NSKeyValueCoding.DefaultImplementation

Enclosing interface:

NSKeyValueCoding

public static class NSKeyValueCoding.DefaultImplementation
extends Object

The NSKeyValueCoding.DefaultImplementation class provides the WebObjects default implementations of the NSKeyValueCoding and NSKeyValueCoding.ErrorHandling interfaces.

See Also:

NSKeyValueCoding.ErrorHandling, NSKeyValueCoding

Method Summary

static Object	handleQueryWithUnboundKey(Object object, String key) Invoked from valueForKey when it finds no property binding for key.
static void	handleTakeValueForUnboundKey(Object object, Object value, String key) Throws an NSKeyValueCoding.UnknownKeyException with object as the exception's object and key as the exception's key.
static void	takeValueForKey(Object object, Object value, String key) Sets object's property identified by key to value, or invokes handleTakeValueForUnboundKey.
static void	unableToSetNullForKey(Object object, String key) Invoked from takeValueForKey when it is given a null value for a scalar property (such as an int or a float).
static Object	valueForKey(Object object, String key) Retrieves the value associated with the property named key on object.

Methods inherited from class java.lang.Object

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

Method Detail

valueForKey

public static Object valueForKey(Object object,
                                 String key)

Retrieves the value associated with the property named key on object.

The default implementation searches first for a method and (if canAccessFieldsDirectly is true) for instance variables matching key. For example, for key "foo" the search order is as follows: (a) method "getFoo"; (b) method "foo"; (c) method "isFoo"; (d) method "_getFoo"; (e) method "_foo"; (f) method "_isFoo"; (g) field "_foo"; (h) field "_isFoo"; (i) field "foo"; (j) field "isFoo". If an unknown key is encountered and the object implements the NSKeyValueCoding.ErrorHandling interface, handleQueryWithUnboundKey is invoked, otherwise a NSKeyValueCoding.UnknownKeyException is raised.

Parameters:

object - the object to operate upon

key - identifies the property to retrieve

Returns:

object's value for the property identified by key, or invokes handleQueryWithUnboundKey

See Also:

NSKeyValueCoding.valueForKey(java.lang.String)

takeValueForKey

public static void takeValueForKey(Object object,
                                   Object value,
                                   String key)

Sets object's property identified by key to value, or invokes handleTakeValueForUnboundKey.

The default implementation searches for a method or instance variable fitting a pattern for the key. For example, for key "foo" the search order is as follows: (a) method "setFoo"; (b) method "_setFoo"; (c) field "_foo"; (d) field "_isFoo"; (e) field "foo"; (f) field "isFoo". If an unknown key is encountered and the object implements the NSKeyValueCoding.ErrorHandling interface, handleTakeValueForUnboundKey is invoked, otherwise a NSKeyValueCoding.UnknownKeyException is raised.

Parameters:

object - object whose property is set to value

value - key is set to this value

key - identifies the property of an object

See Also:

NSKeyValueCoding.takeValueForKey(java.lang.Object, java.lang.String)

handleQueryWithUnboundKey

public static Object handleQueryWithUnboundKey(Object object,
                                               String key)

Invoked from valueForKey when it finds no property binding for key. The default implementation raises an NSKeyValueCoding.UnknownKeyException.

Parameters:

object - the object involved in the error

key - the key which generated the bad query

Returns:

custom implementations may return any Object instead of throwing an UnknownKeyException

Throws:

an - NSKeyValueCoding.UnknownKeyException with object as the exception's object and key as the exception's key

See Also:

NSKeyValueCoding.valueForKey(java.lang.String), NSKeyValueCoding.ErrorHandling, NSKeyValueCoding.UnknownKeyException

handleTakeValueForUnboundKey

public static void handleTakeValueForUnboundKey(Object object,
                                                Object value,
                                                String key)

Throws an NSKeyValueCoding.UnknownKeyException with object as the exception's object and key as the exception's key. Invoked from takeValueForKey when it finds no property binding for key. The default implementation raises an NSKeyValueCoding.UnknownKeyException

Parameters:

object - the object involved in the error

value - the value which could not be set

key - the key which generated the error

Throws:

NSKeyValueCoding.UnknownKeyException - when it finds no property binding for key

See Also:

NSKeyValueCoding.takeValueForKey(java.lang.Object, java.lang.String), NSKeyValueCoding.ErrorHandling

unableToSetNullForKey

public static void unableToSetNullForKey(Object object,
                                         String key)

Invoked from takeValueForKey when it is given a null value for a scalar property (such as an int or a float). The default implementation raises an IllegalArgumentException.

Parameters:

object - the object whose value is to be set

key - the key which generated the error

Throws:

IllegalArgumentException - when it is given a null value for a scalar property

See Also:

NSKeyValueCoding.takeValueForKey(java.lang.Object, java.lang.String), NSKeyValueCoding.ErrorHandling