HoudahFoundation

The HoudahFoundation framework builds upon and extends Apple’s WebObjects Foundation framework. As such it also relies on the JDK’s core libraries.

The WebObjects Foundation framework provides a set collection types (NSArray, NSDictionary, ...). The HoudahFoundation has utility methods to perform common operations on these types. There are also utility methods that apply to core JDK types (String, Integer, ...). Anything you may want to do to a collection type (transformation, persistence, ...) is very likely to be already taken care of by one of these utility classes.

The HoudahFoundation framework implements a large collection of formatter objects. Formatters extend from java.text.Format. They allow the often bidirectional transformation between objects and their String representation. These operations are referred to as “parsing” and “formatting”. We leave it up to the JavaDoc to document each individual formatter.

An object of special interest in the HoudahFoundation framework is the KeyFormatter class. Despite what its name might suggest, this is not a formatter. It rather is a couple made up of a key path (c.f. NSKeyValueCodingAdditions) and a formatter. Often times when displaying an object we want to say: “follow that key path and then format the value at its end”. This operation can be described using a KeyFormatter. The actual formatter wrapping this operation is called KeyFormatterFormatter. It allows for the applying of a KeyFormatter or a series thereof to an object. A KeyFormatterFormatter may be used anywhere a formatter is expected for formatting a value.

Special attention should be given to the Delegate class. It allows for the implementation in the Houdah frameworks of the delegate pattern. This pattern is very common in the WebObjects frameworks. The Delegate implementation expects the publisher of a delegate API to declare a Java interface comprising all the methods the delegate could possibly be expected to implement. This Java interface should be thought of as an “informal protocol”. A delegate is not required to implement all of the interface’s methods. Consequently the delegate need not (and should not) be declared as implementing the interface. It needs only to match the method signature for the calls it is interested in. The master object will call upon the delegate where possible, and drop back to default behavior in all other cases.