Generic, Null-safe, Immutable Collections and Functional Transformations for the JVM
Paguro is designed to: 1. Make Functional Programming simpler and easier in Java. 2. Decrease the number of things you need to think about when coding.
Removing distractions leaves you more energy for creativity and problem-solving. Paguro lets you forget about:
xformArray(myArray)to encapsulate arrays)
Kotlin fixes almost all these issues too, but if you're stuck in Java, Paguro is a great solution.
Type-safe, null-safe versions of Clojure's immutable/persistent collections, an immutable alternative to Java 8 Streams that handles checked exceptions in lambdas, and other tools to make functional programming in Java easier.
Paguro is short for the Latin "Paguroidea" - the name of the Hermit Crab superfamily in Biology. These collections grow by adding a new shell, leaving the insides the same, much the way Hermit Crabs trade up to a new shell when they grow.
vec("one", "two", "three")- an immutable vector/list of three strings
set(3, 5, 7)- an immutable set of three integers
tup("Alice", 11, 3.14)- an immutable 3-field tuple or record
map(tup(1, "single"), tup(2, "double"), tup(3, "triple"))- an immutable map that uses integers to look up appropriate strings.
Usage examples are implemented as unit tests to ensure that they remain correct and current.
You are on the Paguro Classic, or main branch of this project. If you work with pure Java, or a mix of Java and Kotlin files, this is your branch. If you want to live dangerously, try the all-Kotlin version in the 4.0 branch when it becomes available.
@jafingerhut has found bugs in the RRB Tree join implementation. See issue 31 and 36. I normally try to fix bugs promptly, this issue requires more thought! If anyone knows of a paper with a working algorithm for merging two n-ary BTrees, let us know!
Check the Change Log for details of recent changes.
It started with a Software Engineering Stack Exchange question: Why doesn't Java provide immutable collections?
Why Java? That said, this could become a Kotlin-based project.
Java™ is a registered trademark of the Oracle Corporation in the US and other countries. Paguro is not part of Java. Oracle is in no way affiliated with the Paguro project.
Paguro is not part of Clojure. Rich Hickey and the Clojure team are in no way affiliated with the Paguro project, though it borrows heavily from their thoughts and is partly a derivative work of their open-source code.
The Clojure collections are licensed under the Eclipse Public License. Versions of them have been included in this project and modified to add type safety and implement different interfaces. These files are still derivative works under the EPL.
Unless otherwise stated, the rest of this work is licensed under the Apache 2.0 license. New contributions should be made under the Apache 2.0 license whenever practical. I believe it is more popular, clearer, and has been better tested in courts of law.
Hermit Crab Photo by Rushen
Questions? Ideas? Feedback? Use the Google Group Email List. Clear bugs or simple pull requests can be made on Github without discussing them first on the email list.
If you submit a patch, please: - Keep the changes minimal (don't let your IDE reformat whole files). - Try to match the code style as best you can. - Clearly document your changes. - Update the unit tests to clearly and simply prove that your code works. - It's a good idea to discuss proposed changes on the email list before you spend time coding.
The pre-built jar file is the easiest way to use Paguro. Users typically only build Paguro from source to make a contribution, or to experiment with the source code.
Paguro is usually built on Ubuntu 18.04 and later with
maveninstalled from the official repositories. Being Java it should theoretically build with JDK 11+ on any system.
Depending on how you installed Java and Maven, you may need to set some of the following in your
~/.profilefile and reboot (or source that file like
. ~/.profilefrom the command line you will use for the build). Or do whatever Windows does. If your tools are installed in different directories, you will have to fix the following:
bash export JDK_HOME=/usr/lib/jvm/java-11-openjdk-amd64 export JAVA_HOME=$JDK_HOME/jre export M2_HOME=$TOOLS/apache-maven-3.3.9/ export M2="$M2_HOME"bin export PATH=$PATH:$M2
# Start in an appropriate directory
You need TestUtils for Paguro's equality testing.
The first time you build, get a local copy of that and Paguro
cd Paguro git pull mvn clean install
Additional information is in: README2.md.