App Metadata (`NucleusApp`)¶

Access application metadata injected by the Nucleus Gradle plugin at runtime.

Installation¶

NucleusApp is part of core-runtime:

dependencies {
    implementation("io.github.kdroidfilter:nucleus.core-runtime:<version>")
}

Usage¶

import io.github.kdroidfilter.nucleus.core.runtime.NucleusApp

// Application identifier (matches packageName in the Nucleus DSL)
val appId: String = NucleusApp.appId

// Optional metadata (null if not configured in the DSL)
val version: String? = NucleusApp.version
val vendor: String? = NucleusApp.vendor
val description: String? = NucleusApp.description

// Check if the plugin injected metadata
if (NucleusApp.isConfigured) {
    println("Running as packaged app: $appId v$version")
}

Properties¶

Property	Type	Description
`appId`	`String`	Application identifier. Falls back to main class name or `"NucleusApp"` if not injected.
`version`	`String?`	Application version from `packageVersion` in the DSL. `null` if not configured.
`vendor`	`String?`	Application vendor from `vendor` in the DSL. `null` if not configured.
`description`	`String?`	Application description from `description` in the DSL. `null` if not configured.
`isConfigured`	`Boolean`	`true` if the Nucleus plugin injected metadata (via system property or classpath resource).

All properties are @JvmStatic and lazily initialized.

How It Works¶

The Nucleus Gradle plugin injects metadata through two mechanisms:

1. System properties (during `run`)¶

When running via ./gradlew run, the plugin adds JVM arguments:

-Dnucleus.app.id=MyApp

2. Classpath resource (in packaged builds)¶

At build time, the plugin generates a nucleus/nucleus-app.properties file that is included in the application's classpath:

app.id=MyApp
app.version=1.2.3
app.vendor=My Company
app.description=My awesome desktop app

Resolution order¶

For each property, NucleusApp checks (first non-null wins):

System property (nucleus.app.id, nucleus.app.version, etc.)
Classpath resource (nucleus/nucleus-app.properties)
Legacy fallback (for appId only): main class from sun.java.command, then "NucleusApp"

Use Cases¶

About dialog¶

@Composable
fun AboutDialog() {
    Column {
        Text("${NucleusApp.appId}")
        NucleusApp.version?.let { Text("Version $it") }
        NucleusApp.vendor?.let { Text("By $it") }
    }
}

Conditional logic based on packaging¶

if (NucleusApp.isConfigured) {
    // Running as packaged app — enable auto-update, telemetry, etc.
    initAutoUpdater()
} else {
    // Running in dev mode (./gradlew run)
    enableDevTools()
}

Used by other Nucleus modules¶

NucleusApp.appId is consumed automatically by:

SingleInstanceManager — uses appId as the default lock file identifier (via AppIdProvider)
taskbar-progress — uses appId to resolve the Linux .desktop file for D-Bus progress
updater-runtime — uses appId to determine the update marker storage directory
GraalVM graalvm-runtime — uses appId to set the correct WM_CLASS on Linux native image

App Metadata (NucleusApp)¶