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Authors
- Mike Kienenberger
-
Date: 2006-02-11 11:22:57 -0700 (Sat, 11 Feb 2006)
Copyright: (C) 1995 Free Software Foundation, Inc.
- Declared in:
- Foundation/NSProtocolChecker.h
Availability: OpenStep
The NSProtocolChecker and NSProxy classes provide message filtering and forwarding capabilities. If you wish to ensure at runtime that a given object will only be sent messages in a certain protocol, you create an
NSProtocolChecker
instance with the protocol and the object as arguments-
id versatileObject = [[ClassWithManyMethods alloc] init]; id narrowObject = [NSProtocolChecker protocolCheckerWithTarget: versatileObject protocol: @protocol(SomeSpecificProtocol)]; return narrowObject;
This is often used in conjunction with distributed objects to expose only a subset of an objects methods to remote processes
Instance Variables
Method summary
+ (id)
protocolCheckerWithTarget: (
NSObject*)anObject
protocol: (Protocol*)aProtocol;
Availability: OpenStep
Allocates and initializes an NSProtocolChecker instance by calling
-initWithTarget:protocol:
Autoreleases and returns the new instance.
- (void)
forwardInvocation: (
NSInvocation*)anInvocation;
Availability: OpenStep
Forwards any message to the delegate if the method is declared in the checker's protocol; otherwise raises an NSInvalidArgumentException
.
- (id)
initWithTarget: (
NSObject*)anObject
protocol: (Protocol*)aProtocol;
Availability: OpenStep
Initializes a newly allocated NSProtocolChecker instance that will forward any messages in the aProtocol protocol to anObject, its delegate. Thus, the checker can be vended in lieu of anObject to restrict the messages that can be sent to anObject. If any method in the protocol returns anObject, the checker will replace the returned value with itself rather than the target object.
Returns the new instance.
- (Protocol*)
protocol;
Availability: OpenStep
Returns the protocol object the checker uses to verify whether a given message should be forwarded to its delegate.
- (
NSObject*)
target;
Availability: OpenStep
Returns the target of the NSProtocolChecker.
Instance Variables for NSProtocolChecker Class
@protected Protocol* _myProtocol;
Warning the underscore at the start of the name of this instance variable indicates that, even though it is not technically private, it is intended for internal use within the package, and you should not use the variable in other code.
@protected NSObject* _myTarget;
Warning the underscore at the start of the name of this instance variable indicates that, even though it is not technically private, it is intended for internal use within the package, and you should not use the variable in other code.
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