dtonhofer
Functional Programming in Java, Second Edition: p. 55 "Compare.java" can be further simplified
On page 55, we see Compare.java
final Function<Person, String> byName = person -> person.getName();
people.stream()
.sorted(comparing(byName));
However, this can be further simplified to:
people.stream()
.sorted(comparing(Person::getName));
On the same page, more from Compare.java:
final Function<Person, Integer> byAge = person -> person.getAge();
final Function<Person, String> byTheirName = person -> person.getName();
printPeople("Sorted in ascending order by age, then name: ",
people.stream()
.sorted(comparing(byAge).thenComparing(byTheirName))
.collect(toList());
which can be simplified similarly to:
printPeople("Sorted in ascending order by age, then name: ",
people.stream()
sorted(comparing(Person::getAge).thenComparing(Person::getName))
.collect(toList());
but which would be even better by separating the list generation and output tasks:
List<Person> asc =
people.stream()
.sorted(comparing(Person::getAge).thenComparing(Person::getName))
.collect(toList());
printPeople("Sorted in ascending order by age, then name: ", asc);
…all according to the JavaDoc for Comparator:
P.S.
Would it be clearer to explicitly write the class from which comparing() comes instead of assuming it has been imported statically? Like this:
people.stream()
.sorted(Comparator.comparing(Person::getName));
instaed of
people.stream()
.sorted(comparing(Person::getName));
Note that the collect()call
people.stream()
.sorted(comparing(byAge).thenComparing(byTheirName))
.collect(toList()));
…also assume a statically imported toList(). On the other hand, compare/fpij/OlderThan20.java on page 58 is explicit:
List<Person> olderThan20 =
people.stream()
.filter(person -> person.getAge() > 20)
.collect(Collectors.toList());
Popular Pragmatic Bookshelf topics
As per the title, thanks.
New
Hi Travis! Thank you for the cool book! :slight_smile:
I made a list of issues and thought I could post them chapter by chapter. I’m rev...
New
The generated iex result below should list products instead of product for the metadata. (page 67)
iex> product = %Product{}
%Pento....
New
Title: Intuitive Python: docker run… denied error (page 2)
Attempted to run the docker command in both CLI and Powershell
PS C:\Users\r...
New
#book-python-testing-with-pytest-second-edition
Hi. Thanks for writing the book. I am just learning so this might just of been an issue ...
New
“The ProductLive.Index template calls a helper function, live_component/3, that in turn calls on the modal component. ”
Excerpt From: Br...
New
Title: Build a Weather Station with Elixir and Nerves: Problem connecting to Postgres with Grafana on (page 64)
If you follow the defau...
New
When installing Cards as an editable package, I get the following error:
ERROR: File “setup.py” not found. Directory cannot be installe...
New
Hi,
I completed chapter 6 but am getting the following error when running:
thread 'main' panicked at 'Failed to load texture: IoError(O...
New
@mfazio23
Android Studio will not accept anything I do when trying to use the Transformations class, as described on pp. 140-141. Googl...
New
Other popular topics
I am thinking in building or buy a desktop computer for programing, both professionally and on my free time, and my choice of OS is Linux...
New
New
Rust is an exciting new programming language combining the power of C with memory safety, fearless concurrency, and productivity boosters...
New
This looks like a stunning keycap set :orange_heart:
A LEGENDARY KEYBOARD LIVES ON
When you bought an Apple Macintosh computer in the e...
New
Hello everyone! This thread is to tell you about what authors from The Pragmatic Bookshelf are writing on Medium.
New
Biggest jackpot ever apparently! :upside_down_face:
I don’t (usually) gamble/play the lottery, but working on a program to predict the...
New
Get the comprehensive, insider information you need for Rails 8 with the new edition of this award-winning classic.
Sam Ruby @rubys
...
New
Explore the power of Ash Framework by modeling and building the domain for a real-world web application.
Rebecca Le @sevenseacat and ...
New
This is a very quick guide, you just need to:
Download LM Studio: https://lmstudio.ai/
Click on search
Type DeepSeek, then select the o...
New
Node.js v22.14.0 has been released.
Link: Release 2025-02-11, Version 22.14.0 'Jod' (LTS), @aduh95 · nodejs/node · GitHub
New
Categories:
Sub Categories:
Popular Portals
- /elixir
- /rust
- /wasm
- /ruby
- /erlang
- /phoenix
- /keyboards
- /python
- /js
- /rails
- /security
- /go
- /swift
- /vim
- /clojure
- /emacs
- /haskell
- /java
- /svelte
- /onivim
- /typescript
- /kotlin
- /crystal
- /c-plus-plus
- /tailwind
- /react
- /gleam
- /ocaml
- /elm
- /flutter
- /vscode
- /ash
- /html
- /opensuse
- /zig
- /centos
- /deepseek
- /php
- /scala
- /react-native
- /lisp
- /sublime-text
- /textmate
- /nixos
- /debian
- /agda
- /django
- /kubuntu
- /deno
- /arch-linux
- /nodejs
- /revery
- /ubuntu
- /manjaro
- /spring
- /diversity
- /lua
- /julia
- /markdown
- /c








