Events: Initial commit.

Author: e3ndr

Events/README.md

@@ -0,0 +1,87 @@
+# Casterlabs Commons/Events
+
+This package has helpers for creating event-based systems.
+
+## Examples
+
+Simple event:
+
+```java
+SingleEventProvider<String> ep = new SingleEventProvider<>();
+
+int taskId = ep.on((location) -> {
+  System.out.printf("Hello %s!\n", location);
+});
+
+ep.fireEvent("world");
+ep.off(taskId);
+```
+
+Advanced usage of MultiEventProvider:
+
+```java
+public class CoffeeMachineMonitor extends MultiEventProvider<CoffeeEventType, CoffeeEvent> {
+
+  public static enum CoffeeEventType {
+    // ...
+  }
+
+  // CoffeeEvent, CoffeeBrewErrorEvent, etc...
+
+}
+```
+
+```java
+CoffeeMachineMonitor mon = new CoffeeMachineMonitor();
+
+ep.on(CoffeeEventType.BREW_FINISHED, () -> {
+  System.out.println("Brew finished!");
+});
+
+ep.on(CoffeeEventType.BREW_ERROR, (e) -> {
+  CoffeeBrewErrorEvent ev = (CoffeeBrewErrorEvent) e;
+  System.out.printf("Error whilst brewing: %s\n", e.getMessage());
+});
+```
+
+## Adding to your project
+
+Replace `_VERSION` with the latest version or commit in this repo and make sure to add the [Repository](https://github.com/Casterlabs/Commons#Repository) to your build system.
+
+<details>
+  <summary>Maven</summary>
+  
+  ```xml
+    <dependency>
+        <groupId>co.casterlabs.Commons</groupId>
+        <artifactId>Async</artifactId>
+        <version>_VERSION</version>
+    </dependency>
+  ```
+</details>
+
+<details>
+  <summary>Gradle</summary>
+  
+  ```gradle
+	dependencies {
+        implementation 'co.casterlabs:Commons.Async:_VERSION'
+	}
+  ```
+</details>
+
+<details>
+  <summary>SBT</summary>
+  
+  ```
+libraryDependencies += "co.casterlabs.Commons" % "Async" % "_VERSION"
+  ```
+</details>
+
+<details>
+  <summary>Leiningen</summary>
+  
+  ```
+:dependencies [[co.casterlabs.Commons/Async "_VERSION"]]	
+  ```
+</details>

Events/pom.xml

@@ -0,0 +1,11 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<artifactId>Events</artifactId>
+
+	<parent>
+		<groupId>co.casterlabs</groupId>
+		<artifactId>Commons</artifactId>
+		<version>1.0.0</version>
+		<relativePath>../pom.xml</relativePath>
+	</parent>
+</project>

Events/src/main/java/co/casterlabs/commons/events/MultiEventProvider.java

@@ -0,0 +1,73 @@
+package co.casterlabs.commons.events;
+
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+import java.util.function.Consumer;
+
+import org.jetbrains.annotations.Nullable;
+
+import lombok.NonNull;
+
+public class MultiEventProvider<E extends Enum<?>, T> {
+    private Map<E, Map<Integer, Consumer<T>>> listenerSections = new HashMap<>();
+    private Set<Integer> allListeners = new HashSet<>();
+
+    /* on */
+
+    public synchronized int on(@NonNull E type, @NonNull Consumer<T> listener) {
+        int id = listener.hashCode();
+        Map<Integer, Consumer<T>> listenerSection = this.listenerSections.get(type);
+
+        if (listenerSection == null) {
+            listenerSection = new HashMap<>();
+            this.listenerSections.put(type, listenerSection);
+        }
+
+        listenerSection.put(id, listener);
+        this.allListeners.add(id);
+
+        return id;
+    }
+
+    public synchronized int on(@NonNull E type, @NonNull Runnable listener) {
+        return this.on(type, (aVoid) -> listener.run());
+    }
+
+    /* off */
+
+    public synchronized void off(@NonNull Consumer<T> listener) {
+        this.off(listener.hashCode());
+    }
+
+    public synchronized void off(@NonNull Runnable listener) {
+        this.off(listener.hashCode());
+    }
+
+    public synchronized void off(int id) {
+        this.allListeners.remove(id);
+
+        for (Map<Integer, Consumer<T>> listenerSection : this.listenerSections.values()) {
+            listenerSection.remove(id);
+        }
+    }
+
+    /* Firing */
+
+    public synchronized void fireEvent(@NonNull E type, @Nullable T data) {
+        Map<Integer, Consumer<T>> listenerSection = this.listenerSections.get(type);
+
+        if (listenerSection != null) {
+            for (Consumer<T> listener : listenerSection.values()) {
+                try {
+                    listener.accept(data);
+                } catch (Throwable t) {
+                    System.err.println("An exception occurred whilst firing event:");
+                    t.printStackTrace();
+                }
+            }
+        }
+    }
+
+}

Events/src/main/java/co/casterlabs/commons/events/SingleEventProvider.java

@@ -0,0 +1,54 @@
+package co.casterlabs.commons.events;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.function.Consumer;
+
+import org.jetbrains.annotations.Nullable;
+
+import lombok.NonNull;
+
+public class SingleEventProvider<T> {
+    private Map<Integer, Consumer<T>> listeners = new HashMap<>();
+
+    /* on */
+
+    public synchronized int on(@NonNull Consumer<T> listener) {
+        int id = listener.hashCode();
+        this.listeners.put(id, listener);
+
+        return id;
+    }
+
+    public synchronized int on(@NonNull Runnable listener) {
+        return this.on((aVoid) -> listener.run());
+    }
+
+    /* off */
+
+    public synchronized void off(@NonNull Consumer<T> listener) {
+        this.off(listener.hashCode());
+    }
+
+    public synchronized void off(@NonNull Runnable listener) {
+        this.off(listener.hashCode());
+    }
+
+    public synchronized void off(int id) {
+        this.listeners.remove(id);
+    }
+
+    /* Firing */
+
+    public synchronized void fireEvent(@Nullable T data) {
+        for (Consumer<T> listener : this.listeners.values()) {
+            try {
+                listener.accept(data);
+            } catch (Throwable t) {
+                System.err.println("An exception occurred whilst firing event:");
+                t.printStackTrace();
+            }
+        }
+    }
+
+}

README.md

@@ -9,7 +9,8 @@ We sort out the different utils into distinct packages, allowing you to pull in
 Select a subproject to get started.
 
 [Platform](/Platform/) • OS & CPU arch detection.  
-[Async](/Async/) • Threading & async helpers.
+[Async](/Async/) • Threading & async helpers.  
+[Events](/Events/) • Event helpers.
 
 ## Repository
 

pom.xml

@@ -8,6 +8,7 @@
 	<modules>
 		<module>Platform</module>
 		<module>Async</module>
+		<module>Events</module>
 	</modules>
 
 	<properties>