Inheritance, Generics and Binary Methods in Java
Herencia, Genéricos y Métodos Binarios en Java
María Lucía Barrón–Estrada 1 and Ryan Stansifer 2
1 Departamento de Sistemas y Computación Instituto Tecnológico de Culiacán Culiacán, Sin. C.P. 80220 México. E–mail: mbarron@fit.edu
2 Computer Science Department Florida Institute of Technology University Blvd.. Melbourne, FL 32901. E–mail: ryan@cs.fit.ed
]]>Abstract
Java has adopted a mechanism to support parameterized types that will be available in the next major release. A draft specification to add generics to the JavaTM Programming Language was published two years ago [1] and a new version of it in June 23, 2003 [2]. An extension of the type system based on F–bounded quantification is proposed. A binary method is a method that has one or more parameters of the same type as the object that receives the message. F–Bounded polymorphism and binary methods can't be combined smoothly in object–oriented languages with nominal subtyping and single dispatch [3].
In this paper, we address some problems that can arise when binary methods are needed in parameterized classes and interfaces in the implementation of a Java program.
Keywords: Binary methods, Inheritance, Java, Parameterized types.
Resumen
El lenguaje de programación Java ha adoptado un mecanismo para definir tipos parametrizados, el cual estará disponible para los usuarios en la próxima versión de su compilador. La primera especificación formal para incluir genéricos en Java fue publicada hace dos años y una nueva versión el pasado mes de Junio del 2003. En esta especificación, se propone extender el sistema de tipos basandose en el sistema de cuantificación restringida F (F–Bounded quantification) con el fin de soportar directamente polimorfismo paramétrico en Java. Un método binario en aquel que contiene uno o más parámetros del mismo tipo del objeto que recibe el mensaje. El polimorfismo basado en el sistema de restricción F y los métodos binarios no pueden ser combinados en forma sencilla en aquellos lenguajes de programación orientados a objectos que contienen un sistema de tipos nominal y basan la selección del metodo a ejecutar solo en el tipo del objeto que recibe el mensaje.
En este articulo, se presentan algunos problemas que aparecen en la implementación de programas en Java cuando es necesario definir clases e interfaces parametrizadas.
Palabras clave: métodos binarios, herencia, Java, tipos parametrizados, genéricos.
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