added discord webhook support

src/dev/asdf00/general/utils/discord/DiscordHook.java

@@ -0,0 +1,111 @@
+package dev.asdf00.general.utils.discord;
+
+import java.io.IOException;
+import java.net.URI;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Queue;
+import java.util.concurrent.ConcurrentLinkedQueue;
+import java.util.concurrent.Executor;
+import java.util.concurrent.Executors;
+
+public final class DiscordHook {
+    private static final HttpClient httpClient = HttpClient.newBuilder()
+            .version(HttpClient.Version.HTTP_2)
+            .build();
+
+    private static final Map<String, DiscordHook> currentHooks = new HashMap<>();
+
+    private final String webhook;
+
+    private final Queue<String> msgQueue = new ConcurrentLinkedQueue<>();
+
+    private final Executor thread = Executors.newSingleThreadExecutor();
+
+    private final Object lockObject = new Object();
+
+    private int timeoutInMillis = 5000;
+
+    private DiscordHook(String webhook) {
+        this.webhook = webhook;
+    }
+
+    /**
+     * Send a message to the associated discord webhook.
+     *
+     * @param splitMessage determines if the message should be pruned or split into
+     *                     multiple messages if it is lager than 2000 characters
+     * @param msg          the message to be sent
+     * @param args         arguments to be formatted into the message
+     */
+    public void sendMsg(boolean splitMessage, String msg, Object... args) {
+        var pmsg = String.format(msg, args);
+        int cnt = 1;
+        if (!splitMessage && pmsg.length() > 1994) {
+            // large message with pruning
+            msgQueue.add(pmsg.substring(0, 1995) + " [...]");
+        } else if (pmsg.length() > 2000) {
+            // large message with splitting
+            var ms = new ArrayList<String>(pmsg.length() / 2000 + 1);
+            for (int i = 0; i < ms.size(); i++) {
+                ms.add(pmsg.substring(i * 2000, Math.min(pmsg.length(), (i + 1) * 2000 + 1)));
+            }
+            msgQueue.addAll(ms);
+            cnt = ms.size();
+        } else {
+            // small message
+            msgQueue.add(pmsg);
+        }
+
+        // schedule all messages inserted into the queue
+        for (; cnt > 0; cnt--) {
+            thread.execute(this::scheduleMsg);
+        }
+    }
+
+    private static String wrapIntoJson(String msg) {
+        return String.format("{\"content\": \"%s\"}", msg);
+    }
+
+    private void scheduleMsg() {
+        try {
+            var json = msgQueue.remove();
+            synchronized (lockObject) {
+                var postRequest = HttpRequest.newBuilder()
+                        .POST(HttpRequest.BodyPublishers.ofString(json))
+                        .uri(URI.create(webhook))
+                        .setHeader("User-Agent", "JavaCrawler")
+                        .header("Content-Type", "application/json")
+                        .build();
+                httpClient.send(postRequest, HttpResponse.BodyHandlers.ofString());
+                Thread.sleep(timeoutInMillis);
+            }
+        } catch (InterruptedException | IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    /**
+     * Sets the timeout for rate limiting. Default is 5 seconds.
+     */
+    public void setTimeout(int timeout) {
+        timeoutInMillis = timeout;
+    }
+
+    /**
+     * Gets the instance associated with this webhook or creates a new one if no instance was found.
+     *
+     * @param webhook the URI of the discord webhook
+     * @return instance associated with the given webhook
+     */
+    public static synchronized DiscordHook getInstance(String webhook) {
+        if (!currentHooks.containsKey(webhook)) {
+            currentHooks.put(webhook, new DiscordHook(webhook));
+        }
+        return currentHooks.get(webhook);
+    }
+}

src/dev/asdf00/general/utils/extras/Tuple.java

@@ -0,0 +1,11 @@
+package dev.asdf00.general.utils.extras;
+
+public class Tuple<A, B> {
+    public A a;
+    public B b;
+    public Tuple() { }
+    public Tuple(A a, B b) {
+        this.a = a;
+        this.b = b;
+    }
+}

src/module-info.java

@@ -1,4 +1,7 @@
 module GeneralUtils {
     requires jdk.unsupported;
+    requires java.net.http;
+    exports dev.asdf00.general.utils.discord;
+    exports dev.asdf00.general.utils.extras;
     exports dev.asdf00.general.utils.list;
 }