Dynamic object communication protocol

摘要

The present invention provides a uniform method for dynamically determining an object's communication requirements. The invention provides the ability to determine the requirements for communicating with an object regardless of the object's implementation (i.e., whether keys were implemented as methods or instance variables). The invention is used in conjunction with the runtime description of an object to provide a technique for communicating with an object. The present invention uses "key-value coding" to represent data. Key-value coding uses a dictionary of key-value pairs to represent a property and a value of the property. For example, a data value, "Joe" stored in a column of a database table that contains employees' first names is represented in a key-value pair as: Key="firstName", Value="Joe". The property of the key in this key-value pair is "firstName". The method for loading data into an object is "takeValuesFromDictionary". This method takes a dictionary of key-value pairs and in the default implementation it runs through that dictionary and looks for any key names that match the "get" or "set" method call. The method for getting values is valuesForKeys:, which extracts the value for each key in the array passed in and returns the key-value pairs in a dictionary.