Practical ObjectOriented Development with UML and Java

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Practical Object-Oriented Development with UML
and Java

• Chapter 2The Object-Oriented Paradigm

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13 Principles Of Object-Orientation

• Encapsulation
• Information Hiding
• Message Passing
• Late Binding
• Delegation
• Class/Instance/Object
• Generalization/Specialization without Polymorphism

• Generalization/Specialization with Polymorphism
• Relationships
• Interface/Instance/Object
• Generalization/Specialization of Relationships
• Reflection
• Multi-threading

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Principle 1

• Encapsulation
• The object contains both the data and the methods
  that will manipulate or change that data.

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Principle 2

• Information Hiding
• The object that contains the attributes defines
  what services are available to the other objects.
  In fact, other objects have neither access nor
  knowledge of the data or how a service is provided

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Principle 3.

• Message Passing
• An object may communication with another object
  only via a message passing mechanism.

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Principle 4.

• Late Binding
• Support for the ability to determine the specific
  receiver and its corresponding method to be
  executed for a message at run time.

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Principle 5.

• Delegation
• Work is passed, via message passing, from one
  object (client) to another object (server)
  because, from the clients perspective, the agent
  has the services that the client nedds. Work is
  continuously passed until it reaches the object
  that has both the data and the method to perform
  the work.

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Principle 6.

• Class/Instance/Object
• All objects are instances of a class. Instances
  can be created or destroyed at run time.

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Principle 7.

• Generalization/Specialization without
  Polymorphism
• Classes can be organized in a hierarchical
  inheritance structure representing a
  generalization/specialization relationship. In
  the structure, the the specialized class inherits
  the attributes, relationships, prototypes, and
  methods from the generalized class that is higher
  in the tree.

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Principle 8.

• Generalization/Specialization with Polymorphism
• Classes can be organized by using a hierarchical
  inheritance structure. In the structure, the
  subclass inherits the attributes, relationships,
  prototypes, and methods from the superclass that
  is higher in the tree. However, a subclass my
  create its own method to replace a method of its
  superclasses in providing a service.

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Principle 9.

• Relationships
• Collaborations between objects to provide a
  service to a client are captured by an
  association relationship, which is technically
  called a link.

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Principle 10.

• Interface/Instance/Object
• All objects that implement an interface are also
  instances of that interface. However, instances
  of an interface cannot be created or destroyed as
  an interface instance. Each object must be
  created or destroyed as an instance of the class
  to which it belongs.

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Principle 11.

• Generalization/Specialization of Interfaces
• Interfaces can be organized by using a
  hierarchical inheritance structure. In the
  structure, the specialized interface inherits the
  service protocol from the generalized interfaces
  that are higher in the tree.

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Principle 12.

• Reflection
• Each object knows the detailed information about
  the classes and interfaces to which it is an
  instance. This means that an application can, at
  runtime, acquire detailed information about the
  object from the object itself.

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Principle 13.

• Multithreading
• Each object can have concurrent execution paths.
  This means that an object can handle multiple
  events (or service requests) in a concurrent
  manner.