LockObserveList implementation, tests for Lock and List

event-loop/src/main/java/mc/core/events/lock/LockObserveList.java

@@ -0,0 +1,44 @@
+package mc.core.events.lock;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.function.Consumer;
+
+public class LockObserveList implements Consumer<PoorMansLock> {
+    private List<PoorMansLock> locks = new ArrayList<>();
+    private Runnable callback;
+
+    public void setCallback(Runnable callback) {
+        this.callback = callback;
+    }
+
+    public void add(PoorMansLock lock) {
+        locks.add(lock);
+        lock.addCallback(this);
+    }
+
+    public void release() {
+        for (PoorMansLock lock : locks) {
+            lock.removeCallback(this);
+        }
+        locks.clear();
+    }
+
+    public boolean isReady() {
+        for (PoorMansLock lock : locks) {
+            if (lock.isLocked())
+                return false;
+        }
+        return true;
+    }
+
+    @Override
+    public void accept(PoorMansLock lock) {
+        if (!lock.isLocked()) {
+            if (isReady()) {
+                if (callback != null)
+                    callback.run();
+            }
+        }
+    }
+}

event-loop/src/test/java/mc/core/events/LockTest.java

@@ -0,0 +1,90 @@
+package mc.core.events;
+
+import mc.core.events.lock.LockObserveList;
+import mc.core.events.lock.PoorMansLock;
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+public class LockTest {
+    @Test
+    public void basicTest() throws InterruptedException {
+        AtomicBoolean engageCallbackCalled = new AtomicBoolean(false);
+        AtomicBoolean disengageCallbackCalled = new AtomicBoolean(false);
+
+        PoorMansLock lock = new PoorMansLock();
+        lock.addCallback(lock1 -> {
+            if (lock1.isLocked())
+                engageCallbackCalled.set(true);
+            else
+                disengageCallbackCalled.set(true);
+        });
+        lock.lock();
+        Assert.assertTrue("Lock is not locked", lock.isLocked());
+        Assert.assertTrue("Engage callback was not called", engageCallbackCalled.get());
+
+        engageCallbackCalled.set(false);
+        try {
+            lock.lock();
+            Assert.assertFalse("Engage callback was called from attempt to block from the same thread", engageCallbackCalled.get());
+        } catch (Exception ex) {
+            Assert.fail("Exception fired while attempting to lock from the same thread");
+            return;
+        }
+
+        Assert.assertFalse("Disengage callback was called while not actually disengaging [x1]", disengageCallbackCalled.get());
+
+        AtomicBoolean lockExceptionFired = new AtomicBoolean(false);
+        AtomicBoolean unlockExceptionFired = new AtomicBoolean(false);
+        CountDownLatch latch = new CountDownLatch(1);
+        new Thread(() -> {
+            try {
+                lock.lock();
+            } catch (Exception ex) {
+                lockExceptionFired.set(true);
+            }
+            try {
+                lock.unlock();
+            } catch (Exception ex) {
+                unlockExceptionFired.set(true);
+            }
+            latch.countDown();
+        }).start();
+
+        latch.await();
+        Assert.assertTrue("Exception was not fired on concurrent lock attempt", lockExceptionFired.get());
+        Assert.assertTrue("Exception was not fired on non-owner unlock attempt", unlockExceptionFired.get());
+        Assert.assertFalse("Disengage callback was called while not actually disengaging [x2]", disengageCallbackCalled.get());
+
+        lock.unlock();
+        Assert.assertTrue("Disengage callback was on called on lock disengage", disengageCallbackCalled.get());
+    }
+
+    @Test
+    public void observeListTest() {
+        PoorMansLock lock1 = new PoorMansLock();
+        PoorMansLock lock2 = new PoorMansLock();
+
+        LockObserveList list = new LockObserveList();
+        list.add(lock1);
+        list.add(lock2);
+
+        Assert.assertTrue("LockObserveList was no able to correctly identify lock states for unlocked locks", list.isReady());
+        lock1.lock();
+        Assert.assertFalse("LockObserveList was no able to correctly identify lock states for list with one locked lock", list.isReady());
+
+
+        AtomicBoolean listReadyCallbackCalled = new AtomicBoolean(false);
+        list.setCallback(() -> listReadyCallbackCalled.set(true));
+        lock2.lock();
+
+        Assert.assertFalse("Callback was called when another lock got engaged", listReadyCallbackCalled.get());
+        lock1.unlock();
+        Assert.assertFalse("Callback was called while one lock is still locked", listReadyCallbackCalled.get());
+        lock2.unlock();
+        Assert.assertTrue("Callback was not called when both locks are actually free", listReadyCallbackCalled.get());
+
+    }
+}