[Add] AutoSender 增加自动发送器接口;

[Add] RandomIntervalSendTimer 增加随机延迟自动发送器;
[Add] RecommendArtworksSender 增加随机排行榜作品发送器;
[Change] PixivDownload 重新开发 getRanking 方法;

src/main/java/net/lamgc/cgj/bot/RandomIntervalSendTimer.java

@@ -0,0 +1,70 @@
+package net.lamgc.cgj.bot;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.lang.reflect.Field;
+import java.util.Random;
+import java.util.Timer;
+import java.util.TimerTask;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+/**
+ * 随机间隔发送器
+ */
+public class RandomIntervalSendTimer extends TimerTask {
+
+    private final static Timer timer = new Timer("Thread-RIST");
+    private final static Logger log = LoggerFactory.getLogger("RandomIntervalSendTimer");
+    private final Random timeRandom = new Random();
+    private final AutoSender sender;
+    private final long time;
+    private final int floatTime;
+    private AtomicBoolean loop = new AtomicBoolean();
+    private final AtomicBoolean start = new AtomicBoolean();
+
+
+    public RandomIntervalSendTimer(AutoSender sender, long time, int floatTime) {
+        this.sender = sender;
+        this.time = time;
+        this.floatTime = floatTime;
+    }
+
+    public void start() {
+        start(this.loop.get());
+    }
+
+    public void start(boolean loop) {
+        this.loop.set(loop);
+        long nextDelay = time + timeRandom.nextInt(floatTime);
+        log.info("定时器 {} 下一延迟: {}ms", Integer.toHexString(this.hashCode()), nextDelay);
+        if(start.get()) {
+            try {
+                Field state = this.getClass().getSuperclass().getDeclaredField("state");
+                state.setAccessible(true);
+                state.setInt(this, 0);
+                state.setAccessible(false);
+            } catch (NoSuchFieldException | IllegalAccessException e) {
+                e.printStackTrace();
+                return;
+            }
+        }
+        start.set(true);
+        timer.schedule(this, nextDelay);
+    }
+
+    @Override
+    public void run() {
+        sender.send();
+        if (this.loop.get()) {
+            start();
+        }
+    }
+
+    @Override
+    public boolean cancel() {
+        start.set(false);
+        return super.cancel();
+    }
+
+}