Home Java javaTutorial Detailed analysis of the source code of the RandomAccess interface in java

Detailed analysis of the source code of the RandomAccess interface in java

May 28, 2017 am 09:06 AM

This article mainly introduces the relevant information of source code analysis of RandomAccess interface in java. Friends in need can refer to

RandomAccess interface source code analysis in java

RandomAccess is an interface located in the java.util package.

The role of this interface

Comments is written very clearly:

/**
 * Marker interface used by <tt>List</tt> implementations to indicate that
 * they support fast (generally constant time) random access. The primary
 * purpose of this interface is to allow generic algorithms to alter their
 * behavior to provide good performance when applied to either random or
 * sequential access lists.
 * List实现所使用的标记接口,用来表明实现了这些接口的list支持快速(通常是常数时间)随机访问。
 * 这个接口的主要目的是允许一般的算法更改它们的行为,以便在随机或者顺序存取列表时能提供更好的性能。
 * <p>The best algorithms for manipulating random access lists (such as
 * <tt>ArrayList</tt>) can produce quadratic behavior when applied to
 * sequential access lists (such as <tt>LinkedList</tt>). Generic list
 * algorithms are encouraged to check whether the given list is an
 * <tt>instanceof</tt> this interface before applying an algorithm that would
 * provide poor performance if it were applied to a sequential access list,
 * and to alter their behavior if necessary to guarantee acceptable
 * performance.
 * 操作随机访问列表(如ArrayList)的最佳算法在应用于顺序存取列表时,有可能产生二次项行为。
 * 泛型算法列表鼓励在将某个算法应用于顺序存取列表可能导致差的性能之前,先检查给定的列表是否是这个接口的一个实例,
 * 并在需要时去改变这些算法的行为以保证性能。
 * <p>It is recognized that the distinction between random and sequential
 * access is often fuzzy. For example, some <tt>List</tt> implementations
 * provide asymptotically linear access times if they get huge, but constant
 * access times in practice. Such a <tt>List</tt> implementation
 * should generally implement this interface. As a rule of thumb, a
 * <tt>List</tt> implementation should implement this interface if,
 * for typical instances of the class, this loop:

 * 随机访问和顺序存取之间的界限通常是模糊的。例如,一些List实现在变得很大时会导致渐进的非线性访问时间,但实际上是常量访问时间。
 * 这样的List实现通常都应该实现该接口。
 * 一般来说,某个List实现如果(对某些典型的类的实例来说)满足下面的条件,就应该实现这个接口:循环
 * <pre class="brush:php;toolbar:false">
 *   for (int i=0, n=list.size(); i < n; i++)
 *     list.get(i);
 * 
* runs faster than this loop: * 比下面的循环运行速度快。 *
 *   for (Iterator i=list.iterator(); i.hasNext(); )
 *     i.next();
 * 
* *

This interface is a member of the * * Java Collections Framework. * 这个接口是Java集合框架的一员。 * @since 1.4 */ public interface RandomAccess { }

Copy after login

RandomAccess is an empty interface, and

the role of the empty interface is generally to serve as an identifier role.

In layman terms, it is to determine whether a list implements the RandomAcess interface. If it does, use the simple

for loop shown below to access it faster:

for (int i=0, n=list.size(); i < n; i++)
   list.get(i);
Copy after login

If the RandomAcess interface is not implemented, it is faster to use the following iterator to loop through.

for (Iterator i=list.iterator(); i.hasNext(); )
   i.next();
Copy after login

Use instanceof to judge, that is,

 if (list instanceof RandomAccess)
Copy after login

The above is the detailed content of Detailed analysis of the source code of the RandomAccess interface in java. For more information, please follow other related articles on the PHP Chinese website!

Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

AI Hentai Generator

AI Hentai Generator

Generate AI Hentai for free.

Hot Article

R.E.P.O. Energy Crystals Explained and What They Do (Yellow Crystal)
2 weeks ago By 尊渡假赌尊渡假赌尊渡假赌
Repo: How To Revive Teammates
4 weeks ago By 尊渡假赌尊渡假赌尊渡假赌
Hello Kitty Island Adventure: How To Get Giant Seeds
4 weeks ago By 尊渡假赌尊渡假赌尊渡假赌

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

Square Root in Java Square Root in Java Aug 30, 2024 pm 04:26 PM

Guide to Square Root in Java. Here we discuss how Square Root works in Java with example and its code implementation respectively.

Perfect Number in Java Perfect Number in Java Aug 30, 2024 pm 04:28 PM

Guide to Perfect Number in Java. Here we discuss the Definition, How to check Perfect number in Java?, examples with code implementation.

Random Number Generator in Java Random Number Generator in Java Aug 30, 2024 pm 04:27 PM

Guide to Random Number Generator in Java. Here we discuss Functions in Java with examples and two different Generators with ther examples.

Weka in Java Weka in Java Aug 30, 2024 pm 04:28 PM

Guide to Weka in Java. Here we discuss the Introduction, how to use weka java, the type of platform, and advantages with examples.

Armstrong Number in Java Armstrong Number in Java Aug 30, 2024 pm 04:26 PM

Guide to the Armstrong Number in Java. Here we discuss an introduction to Armstrong's number in java along with some of the code.

Smith Number in Java Smith Number in Java Aug 30, 2024 pm 04:28 PM

Guide to Smith Number in Java. Here we discuss the Definition, How to check smith number in Java? example with code implementation.

Java Spring Interview Questions Java Spring Interview Questions Aug 30, 2024 pm 04:29 PM

In this article, we have kept the most asked Java Spring Interview Questions with their detailed answers. So that you can crack the interview.

Break or return from Java 8 stream forEach? Break or return from Java 8 stream forEach? Feb 07, 2025 pm 12:09 PM

Java 8 introduces the Stream API, providing a powerful and expressive way to process data collections. However, a common question when using Stream is: How to break or return from a forEach operation? Traditional loops allow for early interruption or return, but Stream's forEach method does not directly support this method. This article will explain the reasons and explore alternative methods for implementing premature termination in Stream processing systems. Further reading: Java Stream API improvements Understand Stream forEach The forEach method is a terminal operation that performs one operation on each element in the Stream. Its design intention is

See all articles