https://github.com/scijava/app-launcher
UNRELEASED PROTOTYPE
https://github.com/scijava/app-launcher
Last synced: 10 months ago
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UNRELEASED PROTOTYPE
- Host: GitHub
- URL: https://github.com/scijava/app-launcher
- Owner: scijava
- License: bsd-2-clause
- Created: 2024-10-11T03:20:55.000Z (over 1 year ago)
- Default Branch: main
- Last Pushed: 2025-01-14T20:26:26.000Z (about 1 year ago)
- Last Synced: 2025-02-02T03:41:20.495Z (12 months ago)
- Language: Java
- Homepage:
- Size: 132 KB
- Stars: 0
- Watchers: 5
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE.txt
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README
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The SciJava app-launcher provides an entry point into SciJava applications,
notably [Fiji](https://fiji.sc/). Its design synergizes well with the
[Jaunch](https://github.com/apposed/jaunch) native launcher, although
Jaunch is by no means the only solution for the native executable side;
[`jpackage`](https://docs.oracle.com/en/java/javase/21/docs/specs/man/jpackage.html)
or [jDeploy](https://www.jdeploy.com/) should also work for example.
The app-launcher's most major functions are:
* Ensure the version of Java being used is appropriate to app's requirements.
In case it isn't, offer to upgrade Java by downloading a more appropriate version.
* Load classes dynamically, without relying on the system classpath.
* Display a splash window while the application is starting up.
## Supported configuration
The app-launcher uses system properties to configure its behavior:
* `scijava.app.name`: Name of the application being launched.
Used in message dialogs if/when interacting with the user.
* `scijava.app.splash-image`: Resource path to an image for the splash window,
to be loaded using `ClassLoader#getResource`. It can be either its own file
or stored within a JAR file, as long as the resource is on the classpath.
* `scijava.app.look-and-feel`: Fully qualified class name of a Swing
`LookAndFeel` to be set before any UI components are created or shown.
This can be useful to ensure a consistent appearance between the app-launcher
splash and dialog UI with any later application UI, as well as to improve UI
behavior on HiDPI displays using smarter Look & Feels such as
[FlatLaf](https://www.formdev.com/flatlaf/).
* `scijava.app.java-root`: directory containing "bundled" installations of Java.
The `Java.root()` method reports this value if it points to a valid directory.
The `Java.check()` method will look here (via `Java.root()`) for which JVMs
are already present locally, and also unpack any newly downloaded JVM into
this directory.
* `scijava.app.java-links`: URL of a plain text file containing links to
desirable Java bundles. The format is `=` for each platform
(OS+architecture) of Java that you want to support. For example:
```
linux-arm64=https://cdn.azul.com/zulu/bin/zulu21.36.17-ca-jdk21.0.4-linux_aarch64.tar.gz
linux-x64=https://cdn.azul.com/zulu/bin/zulu21.36.17-ca-jdk21.0.4-linux_x64.tar.gz
macos-arm64=https://cdn.azul.com/zulu/bin/zulu21.36.17-ca-jdk21.0.4-macosx_aarch64.tar.gz
macos-x64=https://cdn.azul.com/zulu/bin/zulu21.36.17-ca-jdk21.0.4-macosx_x64.tar.gz
windows-arm64=https://cdn.azul.com/zulu/bin/zulu21.36.17-ca-jdk21.0.4-win_aarch64.zip
windows-x64=https://cdn.azul.com/zulu/bin/zulu21.36.17-ca-jdk21.0.4-win_x64.zip
```
The exact naming is up to you, but for a Java distribution to be downloaded,
the `scijava.app.platform` property must be set and match one of the keys
indicated within the fetched remote resource.
* `scijava.app.java-version-minimum`: The minimum version of Java required by
the application. It can be a standalone number like 11, in which case it is
treated as a major version, or a dot-separated sequence of digits, which case
version comparisons are done digit by digit (see `Versions.compare`).
This value is used by `Java.check()` (via `Java.minimumVersion()`) to
warn the user accordingly if the running Java version is not good enough.
* `scijava.app.java-version-recommended`: The minimum version of Java the
application would *prefer* to use. Same syntax as `java-version-minimum`.
This value is used by `Java.check()` (via `Java.recommendedVersion()`) to
warn the user accordingly if the running Java version is not ideal.
## Provenance
The SciJava app-launcher evolved from the
[ImageJ Launcher](https://github.com/imagej/imagej-launcher),
which was a prior solution for launching [Fiji](https://fiji.sc/).
The imagej-launcher's `ClassLauncher` supported a couple of
Fiji/ImageJ-specific flags that this SciJava app-launcher does not:
**`-ijjarpath `:** This flag provided automatic loading of plugins in
`$HOME/.plugins` as well as from the value(s) of the `ij1.plugin.dirs` system
property, when `` was set to `plugins`. To accomplish an equivalent thing
with the app-launcher, use something like:
```shell
-jarpath plugins:"$HOME"/.plugins:/path1:/path2:/path3
```
rather than:
```shell
-Dij1.plugin.dirs=/path1:/path2:/path3 -jarpath plugins
```
This works because the `org.scijava.launcher.ClassLauncher`'s `-jarpath`
handling splits on colons/semicolons.
**`-ijcp `:** This was an undocumented feature, not used by
normal Fiji/ImageJ launches. You can accomplish something similar using
`-cp ` instead.