Added event system

.github/workflows/publish.yml

@@ -1,13 +1,16 @@
 # .github/workflows/publish.yml
-
 name: Publish
 on:
   release:
     types: [released, prereleased]
+
 jobs:
   publish:
     name: Release build and publish
     runs-on: macOS-latest
+    permissions:
+      contents: read
+      packages: write
     steps:
       - name: Check out code
         uses: actions/checkout@v4
@@ -16,12 +19,19 @@ jobs:
         with:
           distribution: 'zulu'
           java-version: 21
-      - name: Publish to MavenCentral
+      - name: Publish SNAPSHOT to snapshot repo
+        if: github.event.action == 'prereleased'
+        run: ./gradlew publishAllPublicationsToSnapshotsRepository --no-configuration-cache
+        env:
+          GITHUB_ACTOR: ${{ github.actor }}
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Publish release to Maven Central
+        if: github.event.action == 'released'
         run: ./gradlew publishToMavenCentral --no-configuration-cache
         env:
           ORG_GRADLE_PROJECT_mavenCentralUsername: ${{ secrets.MAVEN_CENTRAL_USERNAME }}
           ORG_GRADLE_PROJECT_mavenCentralPassword: ${{ secrets.MAVEN_CENTRAL_PASSWORD }}
           ORG_GRADLE_PROJECT_signingInMemoryKeyId: ${{ secrets.SIGNING_KEY_ID }}
           ORG_GRADLE_PROJECT_signingInMemoryKeyPassword: ${{ secrets.SIGNING_PASSWORD }}
-          ORG_GRADLE_PROJECT_signingInMemoryKey: ${{ secrets.GPG_KEY_CONTENTS }}
-
+          ORG_GRADLE_PROJECT_signingInMemoryKey: ${{ secrets.GPG_KEY_CONTENTS }}

build.gradle.kts

@@ -7,7 +7,7 @@ plugins {
 
 group = "io.github.learn-monitor"
 
-version = "v2.0.0-SNAPSHOT-3"
+version = "s2607b1-SNAPSHOT"
 
 application {
     mainClass.set("de.igslandstuhl.database.Application")
@@ -96,4 +96,16 @@ mavenPublishing {
 }
 tasks.withType<AbstractPublishToMaven>().configureEach {
     dependsOn(tasks.withType<Sign>())
+}
+publishing {
+    repositories {
+        maven {
+            name = "snapshots"
+            url = uri("https://maven.pkg.github.com/Learn-Monitor/student-database")
+            credentials {
+                username = System.getenv("GITHUB_ACTOR") ?: findProperty("gpr.user") as String?
+                password = System.getenv("GITHUB_TOKEN") ?: findProperty("gpr.key") as String?
+            }
+        }
+    }
 }

src/main/java/de/igslandstuhl/database/events/Event.java

@@ -0,0 +1,18 @@
+package de.igslandstuhl.database.events;
+
+public abstract class Event {
+    private boolean cancelled = false;
+
+    public abstract EventType<? extends Event> getType();
+    protected void onCancel() {
+        // Override this method to handle cancellation logic in subclasses
+    }
+
+    public boolean isCancelled() {
+        return this.cancelled;
+    }
+    public void cancel() {
+        this.cancelled = true;
+        onCancel();
+    }
+}

src/main/java/de/igslandstuhl/database/events/EventFilter.java

@@ -0,0 +1,17 @@
+package de.igslandstuhl.database.events;
+
+@FunctionalInterface
+public interface EventFilter<T extends Event> {
+    public boolean filter(T event);
+    @SafeVarargs
+    public static <T extends Event> EventFilter<T> linked(EventFilter<T>... filters) {
+        return event -> {
+            for (EventFilter<T> filter : filters) {
+                if (!filter.filter(event)) {
+                    return false;
+                }
+            }
+            return true;
+        };
+    }
+}

src/main/java/de/igslandstuhl/database/events/EventListener.java

@@ -0,0 +1,55 @@
+package de.igslandstuhl.database.events;
+
+import java.util.HashSet;
+import java.util.LinkedList;
+import java.util.Set;
+
+import de.igslandstuhl.database.Registry;
+
+public abstract class EventListener<T extends Event> {
+    private static final Registry<EventType<?>, Set<EventListener<?>>> listeners = new Registry<>();
+
+    private final ListenerPriority priority;
+
+    public EventListener(ListenerPriority priority) {
+        this.priority = priority;
+    }
+
+    public abstract void onEvent(T event);
+    public abstract EventType<T> getEventType();
+    public EventFilter<T> getFilter() {
+        return event -> true;
+    }
+
+    public ListenerPriority getPriority() {
+        return priority;
+    }
+    public void register() {
+        listeners.get(getEventType()).add(this);
+    }
+
+    public static void register(EventType<?> type) {
+        listeners.register(type, new HashSet<>());
+    }
+
+    @SuppressWarnings("unchecked")
+    private static <T extends Event> Set<EventListener<T>> getListeners(EventType<T> type) {
+        return (Set<EventListener<T>>) (Set<?>) listeners.get(type);
+    }
+    public static <T extends Event> void fireEvent(T event) {
+        Set<EventListener<T>> eventListeners = getListeners(EventType.of(event));
+        if (eventListeners != null) {
+            new LinkedList<>(eventListeners).stream()
+                .filter(listener -> listener.getFilter().filter(event))
+                .sorted((a, b) -> a.getPriority().compareTo(b.getPriority()))
+                .forEach(listener -> {
+                    if (!event.isCancelled()) {
+                        listener.onEvent(event);
+                        if (event.isCancelled() && listener.getPriority() == ListenerPriority.MONITOR) {
+                            throw new IllegalStateException("Event was cancelled but a monitor listener was called.");
+                        }
+                    }
+                });
+        }
+    }
+}

src/main/java/de/igslandstuhl/database/events/EventType.java

@@ -0,0 +1,8 @@
+package de.igslandstuhl.database.events;
+
+public record EventType<T extends Event>(String name) {
+    @SuppressWarnings("unchecked")
+    public static <T extends Event> EventType<T> of(T event) {
+        return (EventType<T>) event.getType();
+    }
+}

src/main/java/de/igslandstuhl/database/events/ListenerPriority.java

@@ -0,0 +1,9 @@
+package de.igslandstuhl.database.events;
+
+public enum ListenerPriority {
+    LOWEST,
+    LOW,
+    HIGH,
+    HIGHEST,
+    MONITOR
+}

src/main/java/de/igslandstuhl/database/server/webserver/WebPath.java

@@ -10,6 +10,7 @@
 import de.igslandstuhl.database.Registry;
 import de.igslandstuhl.database.server.Server;
 import de.igslandstuhl.database.server.resources.ResourceLocation;
+import de.igslandstuhl.database.server.webserver.access.AccessLevel;
 import de.igslandstuhl.database.server.webserver.requests.RequestType;
 
 public record WebPath(RequestType type, String handlerType, List<String> namespaces, String context, AccessLevel accessLevel) {

src/main/java/de/igslandstuhl/database/server/webserver/AccessLevel.java → src/main/java/de/igslandstuhl/database/server/webserver/access/AccessLevel.java

@@ -1,4 +1,4 @@
-package de.igslandstuhl.database.server.webserver;
+package de.igslandstuhl.database.server.webserver.access;
 
 import de.igslandstuhl.database.api.User;