Understanding the Difference between Optional.orElse() and Optional.orElseGet()
Optional.orElse() and Optional.orElseGet() are two methods in Java that help in handling Optional, a container object that may or may not contain a value.
Description of orElse()
orElse() takes a value (other) as an argument. If the Optional is present (contains a value), it returns that value. However, if the Optional is empty, it returns the provided value (other).
Description of orElseGet()
orElseGet() also takes an argument, but this time it's a Supplier functional interface. A Supplier takes no arguments and returns a value. Unlike orElse(), orElseGet() will only invoke the Supplier function when the Optional is empty.
When to Use orElseGet()?
The main difference between orElse() and orElseGet() is when the provided argument would result in an expensive operation. If the Optional is not empty, using orElse() will still perform the provided operation even though it's unnecessary. However, orElseGet() avoids this unnecessary operation, only executing it when needed.
Example
Consider the following example:
<code class="java">Optional<string> myString = Optional.empty(); String result1 = myString.orElse(ExpensiveOperation.getExpensiveString()); // ExpensiveOperation always executed String result2 = myString.orElseGet(() -> ExpensiveOperation.getExpensiveString()); // ExpensiveOperation only executed if Optional is empty</string></code>
Test Case
To illustrate the difference, consider a function that returns an Optional string:
<code class="java">public Optional<string> findMyPhone(int phoneId) { ... }</string></code>
Scenario 1: orElse()
Optional.isPresent() | Used phone |
---|---|
True (redundant call) | NewExpensivePhone |
False | NewExpensivePhone |
Scenario 2: orElseGet()
Optional.isPresent() | Used phone |
---|---|
True | MyCheapPhone |
False | NewExpensivePhone |
As seen in the test case, orElse() always executes the provided function, while orElseGet() only executes it when needed.
Conclusion
Understanding the difference between orElse() and orElseGet() is crucial when working with Optionals. orElseGet() provides an efficient way to handle Optional values by avoiding unnecessary operations when the Optional is present.
The above is the detailed content of When Should I Use Optional.orElseGet() Instead of Optional.orElse()?. For more information, please follow other related articles on the PHP Chinese website!

Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

AI Hentai Generator
Generate AI Hentai for free.

Hot Article

Hot Tools

Safe Exam Browser
Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.

WebStorm Mac version
Useful JavaScript development tools

SAP NetWeaver Server Adapter for Eclipse
Integrate Eclipse with SAP NetWeaver application server.

MinGW - Minimalist GNU for Windows
This project is in the process of being migrated to osdn.net/projects/mingw, you can continue to follow us there. MinGW: A native Windows port of the GNU Compiler Collection (GCC), freely distributable import libraries and header files for building native Windows applications; includes extensions to the MSVC runtime to support C99 functionality. All MinGW software can run on 64-bit Windows platforms.

Atom editor mac version download
The most popular open source editor