Michael Bayne
112 lines
5.2 KiB
Markdown
112 lines
5.2 KiB
Markdown
## What is it?
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Getdown (yes, it's the funky stuff) is a system for deploying Java applications to end-user
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computers, as well as keeping those applications up to date.
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It was designed as a replacement for [Java Web Start](https://docs.oracle.com/javase/8/docs/technotes/guides/javaws/)
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due to limitations in Java Web Start's architecture which are outlined in the
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[rationale](https://github.com/threerings/getdown/wiki/Rationale) section.
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Note: Getdown was designed *in 2004* as an alternative to Java Web Start, because of design choices
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made by JWS that were problematic to the use cases its authors had. It is _not_ a drop-in
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replacement for JWS, aimed to help the developers left in the lurch by the deprecation of JWS in
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Java 9. It may still be a viable alternative for developers looking to replace JWS, but don't
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expect to find feature parity with JWS.
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## How do I use it?
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A tutorial and more detailed specification are available from the [Documentation] page. Questions
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can be posted to the [OOO Libs Google group].
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Note that because one can not rely on users having a JRE installed, you must create a custom
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installer for each platform that you plan to support (Windows, macOS, Linux) that installs a JRE,
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the Getdown launcher jar file, a stub configuration file that identifies the URL at which your real
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app manifest is hosted, and whatever the appropiate "desktop integration" is that provides an icon
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the user can click on. We have some details on the
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[installers](https://github.com/threerings/getdown/wiki/Installers) documentation page, though it
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is unfortunately not very detailed.
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## How does it work?
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The main design and operation of Getdown is detailed on the
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[design](https://github.com/threerings/getdown/wiki/Design) page. You can also browse the
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[javadoc documentation] and [source code] if you're interested in implementation details.
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## Where can I see it in action?
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Getdown was originally written by developers at [OOO] for the deployment of their Java-based
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massively multiplayer games. Try out any of the following games to see it in action:
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* [Puzzle Pirates](https://www.puzzlepirates.com/) - OOO
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* [Spiral Knights](https://www.spiralknights.com/) - OOO
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Getdown is implemented in Java, and is designed to deploy and update JVM-based applications. While
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it would be technically feasible to use Getdown to deploy non-JVM-based applications, it is not
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currently supported and it is unlikely that the overhead of bundling a JVM just to run Getdown
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would be worth it if the JVM were not also being used to run the target application.
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## Release notes
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See [CHANGELOG.md](CHANGELOG.md) for release notes.
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## Obtaining Getdown
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Getdown will likely need to be integrated into your build. We have separate instructions for
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[build integration]. You can also download the individual jar files from Maven Central if needed.
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Getdown is comprised of three Maven artifacts (jar files), though you probably only need the first
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one:
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* [getdown-launcher](http://repo2.maven.org/maven2/com/threerings/getdown/getdown-launcher)
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contains minified (via Proguard) code that you actually run to update and launch your app. It
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also contains the tools needed to build a Getdown app distribution.
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* [getdown-core](http://repo2.maven.org/maven2/com/threerings/getdown/getdown-core) contains the
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core logic for downloading, verifying, patching and launching an app as well as the core logic
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for creating an app distribution. It does not contain any user interface code. You would only
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use this artifact if you were planning to integrate Getdown directly into your app.
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* [getdown-ant](http://repo2.maven.org/maven2/com/threerings/getdown/getdown-ant) contains an Ant
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task for building a Getdown app distribution. See the [build integration] instructions for
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details.
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You can also:
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* [Check out the code](https://github.com/threerings/getdown) and build it yourself.
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* Browse the [source code] online.
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* View the [javadoc documentation] online.
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## JVM Version Requirements
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* Getdown version 1.8.x requires Java 7 VM or newer.
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* Getdown version 1.7.x requires Java 7 VM or newer.
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* Getdown version 1.6.x requires Java 6 VM or newer.
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* Getdown version 1.5 and earlier requires Java 5 VM or newer.
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## Migrating from Getdown 1.7 to Getdown 1.8
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See [this document](https://github.com/threerings/getdown/wiki/Migrating-from-1.7-to-1.8) on the
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changes needed to migrate from Getdown 1.7 to 1.8.
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## Building
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Getdown is built with Maven in the standard ways. Invoke the following commands, for fun and
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profit:
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```
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% mvn compile # builds the classes
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% mvn test # builds and runs the unit tests
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% mvn package # builds and creates jar file
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% mvn install # builds, jars and installs in your local Maven repository
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```
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## Discussion
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Feel free to pop over to the [OOO Libs Google Group] to ask questions and get (and give) answers.
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[Documentation]: https://github.com/threerings/getdown/wiki
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[OOO Libs Google group]: http://groups.google.com/group/ooo-libs
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[source code]: https://github.com/threerings/getdown/tree/master/src/main/java/com/threerings/getdown/launcher
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[javadoc documentation]: https://threerings.github.com/getdown/apidocs/
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[OOO]: https://en.wikipedia.org/wiki/Three_Rings_Design
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[build integration]: https://github.com/threerings/getdown/wiki/Build-Integration
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