How do you control object creation and performance?
Object oriented design (OOD) is a popular approach to software development, organizing data and behavior into reusable and modular units called objects. However, creating and managing objects can have a significant impact on the application's performance, particularly in terms of memory usage, CPU time, and network communication. This article will cover some principles and techniques to control object creation and performance in OOD, such as choosing the right level of abstraction, applying design patterns and principles, using object pools and caches, and measuring and optimizing object performance.
One of the key decisions in OOD is how to define the classes and interfaces that represent your objects. The level of abstraction refers to how general or specific your classes and interfaces are, and how they relate to each other. A high level of abstraction means that your classes and interfaces are more generic and flexible, but also more complex and abstract. A low level of abstraction means that your classes and interfaces are more concrete and simple, but also more rigid and specific. Choosing the right level of abstraction depends on your requirements, domain, and design goals. Generally, you want to balance between simplicity, reusability, and extensibility.
Another way to control object creation and performance is to apply design patterns and principles that help you solve common problems and improve the quality and maintainability of your code. Design patterns are proven solutions to recurring design problems, such as how to create, structure, or communicate between objects, while design principles are general guidelines that help you adhere to good practices. For example, the Factory method is a pattern that defines an interface for creating objects, but allows subclasses to decide which class to instantiate; this can reduce complexity and coupling of object creation. The Singleton pattern ensures that only one instance of a class exists and provides a global access point; this can prevent unnecessary object creation and ensure consistency across the system. Additionally, Dependency injection is a principle stating that objects should not create or look for their dependencies, but receive them from an external source; this can improve testability, modularity, scalability, and reduce coupling and hard-coding of object creation.
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Java performance guidelines from IBM : avoid many of the most common sins: 1-don't create objects inside loops //don't do that for(int i=0;i<n;i ){ Oject o=new MyObject(); } 2-use StringBuilder instead of a series of string concatenation expressions //don't do that s1=s2 s3 s4; //try that StringBuilder sb = new StringBuilder(); for (String s : StringArr) { sb.append(s); } String result = sb.toString(); 3- use primitive types and avoid auto-boxing/unboxing where possible //no Integer myMethod(Integer i) { int result = 5 * i; // 'factor' gets unboxed to 'int' return result; // 'result' gets boxed to 'Integer' } 4-cache frequently used objects 5- allocate collection classes with an explicit capacity instead of allowing them to grow
Sometimes, creating and destroying objects can be expensive and time-consuming, especially if they involve heavy resources or complex initialization. In such cases, you can use object pools and caches to reuse existing objects instead of creating new ones. An object pool is a collection of objects that are created in advance and kept ready for use. When an object is needed, it is taken from the pool, used, and returned to the pool. When an object is not needed, it is not destroyed, but recycled. An object cache is a collection of objects that are created on demand and stored for future use. When an object is needed, it is checked if it exists in the cache, and if not, it is created and added to the cache. When an object is not needed, it is not destroyed, but kept in the cache. Both object pools and caches can improve the performance and efficiency of your application, by reducing the overhead and latency of object creation and destruction.
Finally, to control object creation and performance, you need to measure and optimize the performance of your objects. Performance is a measure of how well your objects perform their tasks, in terms of speed, memory, reliability, or scalability. To measure the performance of your objects, you can use various tools and techniques, such as profiling, benchmarking, logging, or testing. To optimize the performance of your objects, you can use various strategies and techniques, such as refactoring, tuning, parallelizing, or simplifying. Measuring and optimizing object performance can help you identify and eliminate bottlenecks, bugs, or inefficiencies in your code, and improve the quality and user experience of your application.
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