[plugins] Support multi-instance plugins with RepeatablePlugin inte…

…rface (Resolves #1861)
javalin · Apr 28, 2023 · 38ab828 · 38ab828
1 parent c77e580
commit 38ab828
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Showing 3 changed files with 25 additions and 4 deletions.
diff --git a/javalin/src/main/java/io/javalin/plugin/Plugin.kt b/javalin/src/main/java/io/javalin/plugin/Plugin.kt
@@ -10,3 +10,8 @@ import io.javalin.Javalin
 fun interface Plugin {
     fun apply(app: Javalin)
 }
+
+/**
+ * A repeatable plugin is a plugin that can be registered multiple times.
+ */
+interface RepeatablePlugin
diff --git a/javalin/src/main/java/io/javalin/plugin/PluginManager.kt b/javalin/src/main/java/io/javalin/plugin/PluginManager.kt
@@ -4,14 +4,14 @@ import io.javalin.Javalin
 
 class PluginManager {
 
-    private val plugins: MutableMap<Class<out Plugin>, Plugin> = LinkedHashMap()
+    private val plugins: MutableList<Plugin> = mutableListOf()
     private val initializedPlugins: MutableSet<Plugin> = mutableSetOf()
 
     fun register(plugin: Plugin) {
-        if (plugins.containsKey(plugin.javaClass)) {
+        if (plugin !is RepeatablePlugin && plugins.any { it.javaClass == plugin.javaClass }) {
             throw PluginAlreadyRegisteredException(plugin.javaClass)
         }
-        plugins[plugin.javaClass] = plugin
+        plugins.add(plugin)
     }
 
     fun initializePlugins(app: Javalin) {
@@ -22,7 +22,7 @@ class PluginManager {
             event.wsHandlerAdded { anyHandlerAdded = true }
         }
 
-        val pluginsToInitialize = plugins.values.filterNot { initializedPlugins.contains(it) }
+        val pluginsToInitialize = plugins.filterNot { initializedPlugins.contains(it) }
 
         pluginsToInitialize.forEach {
             if (it is PluginLifecycleInit) {

diff --git a/javalin/src/test/java/io/javalin/TestPlugins.kt b/javalin/src/test/java/io/javalin/TestPlugins.kt
@@ -4,11 +4,13 @@ import io.javalin.plugin.Plugin
 import io.javalin.plugin.PluginAlreadyRegisteredException
 import io.javalin.plugin.PluginInitException
 import io.javalin.plugin.PluginLifecycleInit
+import io.javalin.plugin.RepeatablePlugin
 import io.javalin.testing.TestUtil
 import org.assertj.core.api.Assertions.assertThat
 import org.assertj.core.api.Assertions.assertThatThrownBy
 import org.junit.jupiter.api.BeforeEach
 import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.assertDoesNotThrow
 
 class TestPlugins {
 
@@ -79,6 +81,20 @@ class TestPlugins {
         }
     }
 
+    class MultiInstanceTestPlugin : Plugin, RepeatablePlugin {
+        override fun apply(app: Javalin) {}
+    }
+
+    @Test
+    fun `registerPlugin should not throw error for repeatable plugins`() {
+        Javalin.create {
+            assertDoesNotThrow {
+                it.plugins.register(MultiInstanceTestPlugin())
+                it.plugins.register(MultiInstanceTestPlugin())
+            }
+        }
+    }
+
     @Test
     fun `init should throw error if handler is registered in init`() {
         class BadPlugin : Plugin, PluginLifecycleInit {