1 files changed, 201 insertions, 0 deletions
diff --git a/src/main/java/io/trygvis/async/QueueController.java b/src/main/java/io/trygvis/async/QueueController.java
new file mode 100644
index 0000000..a343d42
--- /dev/null
+++ b/src/main/java/io/trygvis/async/QueueController.java
@@ -0,0 +1,201 @@
+package io.trygvis.async;
+
+import io.trygvis.queue.QueueExecutor;
+import io.trygvis.queue.QueueSystem;
+import io.trygvis.queue.SqlEffect;
+import io.trygvis.queue.SqlEffectExecutor;
+import io.trygvis.queue.Task;
+import io.trygvis.queue.TaskEffect;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.sql.Connection;
+import java.sql.SQLException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.Callable;
+import java.util.concurrent.ExecutorCompletionService;
+import java.util.concurrent.ScheduledThreadPoolExecutor;
+
+import static io.trygvis.queue.QueueExecutor.TaskExecutionResult;
+import static io.trygvis.queue.QueueService.TaskExecutionRequest;
+import static io.trygvis.queue.Task.TaskState.NEW;
+
+public class QueueController {
+    private final Logger log = LoggerFactory.getLogger(getClass());
+
+    private final QueueSystem queueSystem;
+
+    private final SqlEffectExecutor sqlEffectExecutor;
+
+    private final TaskEffect taskEffect;
+
+    private final TaskExecutionRequest req;
+
+    public final QueueExecutor queue;
+
+    private boolean shouldRun = true;
+
+    private boolean checkForNewTasks;
+
+    private boolean running;
+
+    private Thread thread;
+
+    private ScheduledThreadPoolExecutor executor;
+
+    private List<Runnable> stopListeners = new ArrayList<>();
+
+    public QueueController(QueueSystem queueSystem, TaskExecutionRequest req, TaskEffect taskEffect, QueueExecutor queue) {
+        this.queueSystem = queueSystem;
+        this.req = req;
+        this.sqlEffectExecutor = queueSystem.sqlEffectExecutor;
+        this.taskEffect = taskEffect;
+        this.queue = queue;
+    }
+
+    public void scheduleAll(final List<Task> tasks) throws InterruptedException {
+        ExecutorCompletionService<TaskExecutionResult> service = new ExecutorCompletionService<>(executor);
+
+        for (final Task task : tasks) {
+            service.submit(new Callable<TaskExecutionResult>() {
+                @Override
+                public TaskExecutionResult call() throws Exception {
+                    return queue.applyTask(taskEffect, task);
+                }
+            });
+        }
+    }
+
+    public void invokeAll(final List<Task> tasks) throws InterruptedException {
+        List<Callable<TaskExecutionResult>> callables = new ArrayList<>(tasks.size());
+        for (final Task task : tasks) {
+            callables.add(new Callable<TaskExecutionResult>() {
+                @Override
+                public TaskExecutionResult call() throws Exception {
+                    return queue.applyTask(taskEffect, task);
+                }
+            });
+        }
+
+        executor.invokeAll(callables);
+    }
+
+    public void hint(final long id) throws SQLException {
+        sqlEffectExecutor.transaction(new SqlEffect.Void() {
+            @Override
+            public void doInConnection(Connection c) throws SQLException {
+                Task task = queueSystem.createTaskDao(c).findById(id);
+
+                try {
+                    scheduleAll(Collections.singletonList(task));
+                } catch (InterruptedException e) {
+                    throw new SQLException(e);
+                }
+            }
+        });
+    }
+
+    public synchronized void addOnStopListener(Runnable runnable) {
+        stopListeners.add(runnable);
+    }
+
+    private class QueueThread implements Runnable {
+        public void run() {
+            while (shouldRun) {
+                List<Task> tasks = null;
+
+                try {
+                    tasks = sqlEffectExecutor.transaction(new SqlEffect<List<Task>>() {
+                        public List<Task> doInConnection(Connection c) throws SQLException {
+                            return queueSystem.createTaskDao(c).findByQueueAndState(queue.queue.name, NEW, req.chunkSize);
+                        }
+                    });
+
+                    log.info("Found {} tasks on queue {}", tasks.size(), queue.queue.name);
+
+                    if (tasks.size() > 0) {
+                        invokeAll(tasks);
+                    }
+                } catch (Throwable e) {
+                    if (shouldRun) {
+                        log.warn("Error while executing tasks.", e);
+                    }
+                }
+
+                // If we found exactly the same number of tasks that we asked for, there is most likely more to go.
+                if (req.continueOnFullChunk && tasks != null && tasks.size() == req.chunkSize) {
+                    log.info("Got a full chunk, continuing directly.");
+                    continue;
+                }
+
+                synchronized (this) {
+                    if (checkForNewTasks) {
+                        log.info("Ping received!");
+                        checkForNewTasks = false;
+                    } else {
+                        try {
+                            wait(req.interval(queue.queue));
+                        } catch (InterruptedException e) {
+                            // ignore
+                        }
+                    }
+                }
+            }
+
+            log.info("Thread for queue {} has stopped.", queue.queue.name);
+            running = false;
+            synchronized (this) {
+                this.notifyAll();
+            }
+        }
+    }
+
+    public synchronized void start(ScheduledThreadPoolExecutor executor) {
+        if (running) {
+            throw new IllegalStateException("Already running");
+        }
+
+        log.info("Starting thread for queue {} with poll interval = {}ms", queue.queue.name, queue.queue.interval);
+
+        running = true;
+        this.executor = executor;
+
+        thread = new Thread(new QueueThread(), "queue: " + queue.queue.name);
+        thread.setDaemon(true);
+        thread.start();
+    }
+
+    public synchronized void stop() {
+        if (!running) {
+            return;
+        }
+
+        log.info("Stopping thread for queue {}", queue.queue.name);
+
+        for (Runnable runnable : stopListeners) {
+            try {
+                runnable.run();
+            } catch (Throwable e) {
+                log.error("Error while running stop listener " + runnable, e);
+            }
+        }
+
+        shouldRun = false;
+
+        // TODO: empty out the currently executing tasks.
+
+        thread.interrupt();
+        while (running) {
+            try {
+                wait(1000);
+            } catch (InterruptedException e) {
+                // continue
+            }
+            thread.interrupt();
+        }
+        thread = null;
+        executor.shutdownNow();
+    }
+}