switch the shared pool to a normal threadpool and limit max concurren…

…t threads

also fix #29

src/main/java/lain/lib/SharedPool.java

@@ -1,21 +1,35 @@
 package lain.lib;
 
 import java.util.concurrent.ExecutorService;
-import java.util.concurrent.Executors;
-import java.util.concurrent.ForkJoinPool;
+import java.util.concurrent.LinkedBlockingQueue;
+import java.util.concurrent.ThreadPoolExecutor;
+import java.util.concurrent.TimeUnit;
 
-public final class SharedPool
-{
+public final class SharedPool {
 
-    private static final ExecutorService thePool = Executors.newWorkStealingPool(ForkJoinPool.getCommonPoolParallelism() + 1);
+    private static final ExecutorService thePool = new ThreadPoolExecutor(
+            2,
+            Math.min(Runtime.getRuntime().availableProcessors() * 4, Short.MAX_VALUE),
+            60L,
+            TimeUnit.SECONDS,
+            new LinkedBlockingQueue<>(),
+            SharedPool::newWorker);
 
-    public static void execute(Runnable command)
-    {
-        thePool.execute(command);
+    private SharedPool() {
+        throw new Error("NoInstance");
+    }
+
+    private static Thread newWorker(Runnable target) {
+        Thread thread = new Thread(target, "SharedPoolWorker");
+        if (!thread.isDaemon())
+            thread.setDaemon(true);
+        if (thread.getPriority() != Thread.NORM_PRIORITY)
+            thread.setPriority(Thread.NORM_PRIORITY);
+        return thread;
     }
 
-    private SharedPool()
-    {
+    public static void execute(Runnable command) {
+        thePool.execute(command);
     }
 
 }