What are the advantages and disadvantages of an object-oriented approach to programming

Benefits:

  • The object model is quite natural, since it is primarily focused on the human perception of the world, and not on computer implementation.
  • Classes allow you to construct from useful components with simple tools that abstract away from implementation details.
  • Data and operations on them form a definite entity, and they are not spread throughout the program, as is often the case in procedural programming, but are described together. Localization of code and data improves the visibility and maintainability of software.
  • Encapsulation allows you to introduce modularity, which makes it easier to parallelize the execution of a task across multiple workers and update versions of individual components.
  • The ability to create extensible systems.
  • Using polymorphism is useful when:
    • Processing heterogeneous data structures. Programs can work without distinguishing the type of objects, which greatly simplifies the code. New species can be added at any time.
    • Changes in behavior during execution. At runtime, one object can be replaced with another, which makes it easy, without changing the code, to adapt the algorithm depending on which object is used.
    • Implementation of work with heirs. Algorithms can be generalized so that they can already work with more than one kind of object.
    • Opportunities to describe application-independent parts of the domain in the form of a set of universal classes, or a framework, which will be further expanded by adding parts specific to a particular application.
  • Code reuse:
    • Reduces development time that can be devoted to other tasks.
    • Reusable components usually contain far fewer bugs than newly developed ones, as they have been tested more than once.
    • When a component is used by several clients at once, the improvements made to its code simultaneously have a positive effect on many programs that work with it.
    • When a program relies on standard components, its structure and user interface become more uniform, making it easier to understand and easier to use.

Disadvantages:

  • In complex class hierarchies, fields and methods are usually inherited from different levels. And it is not always easy to determine which fields and methods actually belong to a given class.
  • The code for processing a message is sometimes "smeared" in many methods (in other words, processing a message requires not one, but many methods that can be described in different classes).
  • Documenting classes is more difficult than it was with procedures and modules. Since any method can be overridden, the documentation should say not only what a given method does, but also what context it is called in.
  • Inefficiency and wasteful allocation of memory at runtime (due to overhead of dynamic linking and runtime type checking).
  • Excessive versatility. There are often more methods than the current program actually needs. And since redundant methods cannot be removed, they become dead weight.

Read also:


Comments

Post a Comment

Popular posts from this blog

Methods for reading XML in Java

Image
DOM (Document Object Model) - object - reads XML, recreating it in memory in the form of an object structure, while the XML document is represented as a set of tags - nodes. Each node can have an unlimited number of child nodes. Each child can also contain several levels of descendants or none at all. Thus, the result is a kind of tree. Pluses: Easy to program. If there are many objects in XML with cross-references to each other, it is enough to go through the document twice: first time create objects without references and fill in the name-object dictionary, the second time - restore links. If an error occurs in XML, a half-created XML structure remains in memory, which will be automatically destroyed. Suitable for both reading and writing. Minuses: Low speed. Wastes a lot of memory. SAX (Simple API for XML) - event-driven - reads an XML document, responding to emerging events (opening or closing tag, string, attribute) by calling the event handlers provided by the appl...
Read more

XML, well-formed XML and valid XML

Image
XML, the eXtensible Markup Language, is a language with a simple formal syntax, well suited for creating and manipulating documents with programs, and at the same time easy to read and create documents by humans. XML is extensible, it does not fix the markup used in documents, and the developer is free to create markup in accordance with the needs of a particular area, being limited only by the syntax rules of the language. DTD A DTD, Document Type Definition, is a predefined set of rules that defines the relationships between elements and attributes. For example, the DTD for HTML says that the DIV tag must be inside the BODY tag and can appear multiple times, TITLE - in HEAD and only once, and SCRIPT - both there and there as many times as you want. A DTD is usually described directly in the document as a formulation line starting with <!DOCTYPE ... > or in a separate file. Difference between well-formed XML and valid XML Depending on the level of compliance, the document...
Read more

ArrayList and LinkedList in Java, memory usage and speed

Image
How much extra memory is needed when calling ArrayList.add()? If there is enough space in the array to accommodate a new element, then no additional memory is required. Otherwise, a new array is created, 1.5 times larger than the existing one (this is true for JDK above 1.7, in earlier versions the size of the increase is different). How much extra memory is allocated when you call LinkedList.add()? One new instance of the nested Node class is created. How much memory to store one byte primitive in LinkedList? Each LinkedList element stores a link to the previous element, the next element, and a data link. private static class Node<E> { E item; Node<E> next; Node<E> prev; //... } For 32-bit systems, each link is 32 bits (4 bytes). The object (header) of the nested Node class itself takes 8 bytes. 4 + 4 + 4 + 8 = 20 bytes, and since the size of each object in Java is a multiple of 8, so we get 24 bytes. A byte primitive occupies 1 by...
Read more