1 files changed, 57 insertions, 0 deletions
diff --git a/main/src/cgeo/geocaching/concurrent/BlockingThreadPool.java b/main/src/cgeo/geocaching/concurrent/BlockingThreadPool.java
new file mode 100644
index 0000000..8e60d44
--- /dev/null
+++ b/main/src/cgeo/geocaching/concurrent/BlockingThreadPool.java
@@ -0,0 +1,57 @@
+package cgeo.geocaching.concurrent;
+
+
+import java.util.concurrent.ArrayBlockingQueue;
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.ThreadFactory;
+import java.util.concurrent.ThreadPoolExecutor;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * BlockingThreadPool restricts the amount of parallel threads executing Runnables.
+ */
+public class BlockingThreadPool {
+    /** The queue holding the Runnable. **/
+    private BlockingQueue<Runnable> queue = null;
+    /** The Executor. **/
+    private ThreadPoolExecutor executor;
+
+    /**
+     * Creates a ThreadPool with a given maximum of parallel threads running.
+     * Idle threads will be stopped until new threads are added.
+     *
+     * @param poolSize
+     *            Maximum amout of parallel Threads
+     * @param priority
+     *            The Thread priority e.g. Thread.MIN_PRIORITY
+     */
+    public BlockingThreadPool(int poolSize, int priority) {
+        ThreadFactory threadFactory = new PriorityThreadFactory(priority);
+        this.queue = new ArrayBlockingQueue<Runnable>(poolSize, true);
+        this.executor = new ThreadPoolExecutor(0, poolSize, 5, TimeUnit.SECONDS, this.queue);
+        this.executor.setThreadFactory(threadFactory);
+    }
+
+    /**
+     * Add a runnable to the pool. This will start the core threads in the underlying
+     * executor and try to add the Runnable to the pool. This method waits until timeout
+     * if no free thread is available.
+     *
+     * @param task
+     *            The Runnable to add to the pool
+     * @param timeout
+     *            The timeout to wait for a free thread
+     * @param unit
+     *            The timeout unit
+     * @return true/false successful added
+     * @throws InterruptedException
+     *             Operation was interrupted
+     */
+    public boolean add(Runnable task, int timeout, TimeUnit unit) throws InterruptedException {
+        this.executor.setCorePoolSize(this.executor.getMaximumPoolSize());
+        this.executor.prestartAllCoreThreads();
+        boolean successfull = this.queue.offer(task, timeout, unit);
+        this.executor.setCorePoolSize(0);
+        return successfull;
+    }
+}