0.1.1 | Scheduler shenanigans

README.md

@@ -67,4 +67,73 @@ public class main {
         }
     }
 }
+```
+
+### Usage Scheduler (without retries)
+
+```java
+
+import java.time.Duration;
+
+public class main {
+    public static void main(String[] args) {
+        LicenseScheduler scheduler = LicenseScheduler.startScheduler(
+                Duration.ofMinutes(5),
+                apiUrl,
+                plugin,
+                licenseKey,
+                serverId,
+                result -> {
+                    if (result instanceof LicenseSuccess success) {
+                        if (!success.valid()) {
+                            // Handle invalid license
+                        }
+                    } else if (result instanceof LicenseError error) {
+                        // Log errors if you want
+                    }
+                }
+        );
+        
+        // Later: Stop the scheduler
+        scheduler.stop();
+    }
+}
+```
+
+
+### Usage Scheduler (with retries)
+
+```java
+import java.time.Duration;
+
+public class main {
+    public static void main(String[] args) {
+        LicenseScheduler scheduler = LicenseScheduler.startSchedulerWithRetries(
+                Duration.ofMinutes(5),
+                apiUrl,
+                plugin,
+                licenseKey,
+                serverId,
+                3, //max retries,
+                Duration.ofSeconds(10), //delay between retries
+                result -> {
+                    if(result instanceof LicenseSuccess success) {
+                        if (!success.valid()) {
+                            // Handle invalid license
+                        }
+                    } else if (result instanceof LicenseError error) {
+                        // Log errors if you want
+                    }
+                },
+                result -> {
+                    // Called only after all retries failed
+                    // Put your "offline" handling here
+                    // Disable plugin or something like that
+                }
+        );
+        
+        // Later: Stop the scheduler
+        scheduler.stop();
+    }
+}
 ```

build.gradle

@@ -1,49 +0,0 @@
-plugins {
-    id 'java'
-    id 'maven-publish'
-}
-
-group = 'de.winniepat'
-version = '0.1.0'
-
-
-java {
-    toolchain {
-        languageVersion = JavaLanguageVersion.of(21)
-    }
-    withSourcesJar()
-    withJavadocJar()
-}
-
-repositories {
-    mavenCentral()
-    maven {url = "https://repo.papermc.io/repository/maven-public/" }
-}
-
-dependencies {
-    implementation 'com.google.code.gson:gson:2.13.1'
-}
-
-tasks.named('test') {
-    useJUnitPlatform()
-}
-
-publishing {
-    publications {
-        mavenJava(MavenPublication) {
-            from components.java
-        }
-    }
-
-    repositories {
-        maven {
-            url = uri("https://maven.winniepat.de/repository/maven-releases/")
-
-            credentials {
-                username = project.property("publish.username")
-                password = project.property("publish.password")
-                // the credentials from before are not valid anymore (I am not that dumb)
-            }
-        }
-    }
-}

lib/build.gradle

@@ -1,41 +1,50 @@
-/*
- * This file was generated by the Gradle 'init' task.
- *
- * This generated file contains a sample Java library project to get you started.
- * For more details on building Java & JVM projects, please refer to https://docs.gradle.org/9.5.1/userguide/building_java_projects.html in the Gradle documentation.
- */
-
 plugins {
-    // Apply the java-library plugin for API and implementation separation.
-    id 'java-library'
+    id 'java'
+    id 'maven-publish'
 }
 
-repositories {
-    // Use Maven Central for resolving dependencies.
-    mavenCentral()
-}
+group = 'de.winniepat'
+version = '0.1.1'
 
-dependencies {
-    // Use JUnit Jupiter for testing.
-    testImplementation libs.junit.jupiter
 
-    testRuntimeOnly 'org.junit.platform:junit-platform-launcher'
-
-    // This dependency is exported to consumers, that is to say found on their compile classpath.
-    api libs.commons.math3
-
-    // This dependency is used internally, and not exposed to consumers on their own compile classpath.
-    implementation libs.guava
-}
-
-// Apply a specific Java toolchain to ease working on different environments.
 java {
     toolchain {
         languageVersion = JavaLanguageVersion.of(21)
     }
+    withSourcesJar()
+    withJavadocJar()
+}
+
+repositories {
+    mavenCentral()
+    maven {url = "https://repo.papermc.io/repository/maven-public/" }
+}
+
+dependencies {
+    implementation 'io.papermc.paper:paper-api:1.21.11-R0.1-SNAPSHOT'
+    implementation 'com.google.code.gson:gson:2.13.1'
 }
 
 tasks.named('test') {
-    // Use JUnit Platform for unit tests.
     useJUnitPlatform()
 }
+
+publishing {
+    publications {
+        mavenJava(MavenPublication) {
+            from components.java
+        }
+    }
+
+    repositories {
+        maven {
+            url = uri("https://maven.winniepat.de/repository/maven-releases/")
+
+            credentials {
+                username = project.property("publish.username")
+                password = project.property("publish.password")
+                // the credentials from before are not valid anymore (I am not that dumb)
+            }
+        }
+    }
+}

lib/src/main/java/licenselib/LicenseClient.java

@@ -4,7 +4,7 @@
  * Licensed under the MIT License
  */
 
-package de.winniepat.licenselib;
+package licenselib;
 
 import com.google.gson.*;
 

lib/src/main/java/licenselib/LicenseError.java

@@ -1,4 +1,4 @@
-package de.winniepat.licenselib;
+package licenselib;
 
 /**
  * Represents an error that occurred during the license check process, such as network issues or invalid responses from the server.

lib/src/main/java/licenselib/LicenseScheduler.java

@@ -0,0 +1,194 @@
+package licenselib;
+
+import java.time.Duration;
+import java.util.Objects;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.ScheduledFuture;
+import java.util.concurrent.ThreadFactory;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
+import java.util.function.Consumer;
+
+/**
+ * Periodically checks a license and exposes the most recent result.
+ */
+public final class LicenseScheduler implements AutoCloseable {
+
+    private final ScheduledExecutorService executor;
+    private final ScheduledFuture<?> task;
+    private final AtomicReference<LicenseClient.LicenseResult> lastResult;
+
+    private LicenseScheduler(
+            ScheduledExecutorService executor,
+            ScheduledFuture<?> task,
+            AtomicReference<LicenseClient.LicenseResult> lastResult
+    ) {
+        this.executor = executor;
+        this.task = task;
+        this.lastResult = lastResult;
+    }
+
+    /**
+     * Starts a scheduler that checks the license at the given interval.
+     * @param interval Interval between checks
+     * @param apiUrl Server API url
+     * @param plugin Plugin id matching the one on the backend api
+     * @param licenseKey License key issued by the api
+     * @param serverId Server id matching the one on the backend api
+     * @param onResult Optional callback invoked after every check
+     * @return Scheduler handle for stopping and reading the last result
+     */
+    public static LicenseScheduler startScheduler(
+            Duration interval,
+            String apiUrl,
+            String plugin,
+            String licenseKey,
+            String serverId,
+            Consumer<LicenseClient.LicenseResult> onResult
+    ) {
+        Objects.requireNonNull(interval, "interval");
+        if (interval.isZero() || interval.isNegative()) {
+            throw new IllegalArgumentException("interval must be positive");
+        }
+
+        AtomicReference<LicenseClient.LicenseResult> lastResult = new AtomicReference<>();
+        ThreadFactory threadFactory = runnable -> {
+            Thread thread = new Thread(runnable, "license-scheduler");
+            thread.setDaemon(true);
+            return thread;
+        };
+        ScheduledExecutorService executor = Executors.newSingleThreadScheduledExecutor(threadFactory);
+
+        ScheduledFuture<?> task = executor.scheduleAtFixedRate(() -> {
+            LicenseClient.LicenseResult result = LicenseClient.check(apiUrl, plugin, licenseKey, serverId);
+            lastResult.set(result);
+            if (onResult != null) {
+                onResult.accept(result);
+            }
+        }, 0, interval.toMillis(), TimeUnit.MILLISECONDS);
+
+        return new LicenseScheduler(executor, task, lastResult);
+    }
+
+    /**
+     * Starts a scheduler that retries on errors before invoking offline handling.
+     * @param interval Interval between checks
+     * @param apiUrl Server API url
+     * @param plugin Plugin id matching the one on the backend api
+     * @param licenseKey License key issued by the api
+     * @param serverId Server id matching the one on the backend api
+     * @param maxRetries Number of retries after a failed check
+     * @param retryDelay Delay between retries
+     * @param onResult Optional callback invoked after every attempt
+     * @param onOffline Invoked only after all retries fail
+     * @return Scheduler handle for stopping and reading the last result
+     */
+    public static LicenseScheduler startSchedulerWithRetries(
+            Duration interval,
+            String apiUrl,
+            String plugin,
+            String licenseKey,
+            String serverId,
+            int maxRetries,
+            Duration retryDelay,
+            Consumer<LicenseClient.LicenseResult> onResult,
+            Consumer<LicenseClient.LicenseResult> onOffline
+    ) {
+        Objects.requireNonNull(interval, "interval");
+        Objects.requireNonNull(retryDelay, "retryDelay");
+        if (interval.isZero() || interval.isNegative()) {
+            throw new IllegalArgumentException("interval must be positive");
+        }
+        if (retryDelay.isNegative()) {
+            throw new IllegalArgumentException("retryDelay must not be negative");
+        }
+        if (maxRetries < 0) {
+            throw new IllegalArgumentException("maxRetries must not be negative");
+        }
+
+        AtomicReference<LicenseClient.LicenseResult> lastResult = new AtomicReference<>();
+        ThreadFactory threadFactory = runnable -> {
+            Thread thread = new Thread(runnable, "license-scheduler");
+            thread.setDaemon(true);
+            return thread;
+        };
+        ScheduledExecutorService executor = Executors.newSingleThreadScheduledExecutor(threadFactory);
+
+        ScheduledFuture<?> task = executor.scheduleAtFixedRate(() -> {
+            LicenseClient.LicenseResult result = attemptWithRetries(
+                    apiUrl,
+                    plugin,
+                    licenseKey,
+                    serverId,
+                    maxRetries,
+                    retryDelay,
+                    onResult,
+                    onOffline
+            );
+            lastResult.set(result);
+        }, 0, interval.toMillis(), TimeUnit.MILLISECONDS);
+
+        return new LicenseScheduler(executor, task, lastResult);
+    }
+
+    private static LicenseClient.LicenseResult attemptWithRetries(
+            String apiUrl,
+            String plugin,
+            String licenseKey,
+            String serverId,
+            int maxRetries,
+            Duration retryDelay,
+            Consumer<LicenseClient.LicenseResult> onResult,
+            Consumer<LicenseClient.LicenseResult> onOffline
+    ) {
+        int attempt = 0;
+        LicenseClient.LicenseResult result;
+
+        while (true) {
+            result = LicenseClient.check(apiUrl, plugin, licenseKey, serverId);
+            if (onResult != null) {
+                onResult.accept(result);
+            }
+            if (!(result instanceof LicenseError)) {
+                return result;
+            }
+            if (attempt >= maxRetries) {
+                if (onOffline != null) {
+                    onOffline.accept(result);
+                }
+                return result;
+            }
+            attempt++;
+            if (!retryDelay.isZero()) {
+                try {
+                    Thread.sleep(retryDelay.toMillis());
+                } catch (InterruptedException e) {
+                    Thread.currentThread().interrupt();
+                    return result;
+                }
+            }
+        }
+    }
+
+    /**
+     * Returns the most recent license check result, or null if none has completed yet.
+     * @return The last license check result, or null if not available
+     */
+    public LicenseClient.LicenseResult getLastResult() {
+        return lastResult.get();
+    }
+
+    /**
+     * Stops further checks and shuts down the scheduler.
+     */
+    public void stop() {
+        task.cancel(false);
+        executor.shutdown();
+    }
+
+    @Override
+    public void close() {
+        stop();
+    }
+}

lib/src/main/java/licenselib/LicenseSuccess.java

@@ -1,4 +1,4 @@
-package de.winniepat.licenselib;
+package licenselib;
 
 /**
  * Represents a successful license check result, containing all relevant information about the license status, plugin, customer, and expiration details.

lib/src/main/java/org/example/Library.java

@@ -1,10 +0,0 @@
-/*
- * This source file was generated by the Gradle 'init' task
- */
-package org.example;
-
-public class Library {
-    public boolean someLibraryMethod() {
-        return true;
-    }
-}

lib/src/test/java/org/example/LibraryTest.java

@@ -1,14 +0,0 @@
-/*
- * This source file was generated by the Gradle 'init' task
- */
-package org.example;
-
-import org.junit.jupiter.api.Test;
-import static org.junit.jupiter.api.Assertions.*;
-
-class LibraryTest {
-    @Test void someLibraryMethodReturnsTrue() {
-        Library classUnderTest = new Library();
-        assertTrue(classUnderTest.someLibraryMethod(), "someLibraryMethod should return 'true'");
-    }
-}