[android][database] transaction lock condition 'awaits' now timeouts after 30 seconds if not signalled (forgot to include the handler originally also)

android/src/main/java/io/invertase/firebase/database/RNFirebaseTransactionHandler.java

@@ -0,0 +1,70 @@
+package io.invertase.firebase.database;
+
+import java.util.Map;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.locks.Condition;
+import java.util.concurrent.locks.ReentrantLock;
+
+
+public class RNFirebaseTransactionHandler {
+  private final ReentrantLock lock;
+  private final Condition condition;
+  private Map<String, Object> data;
+  private volatile boolean isReady;
+
+  public Object value;
+  public boolean interrupted;
+  public boolean abort = false;
+
+  RNFirebaseTransactionHandler() {
+    lock = new ReentrantLock();
+    condition = lock.newCondition();
+  }
+
+  /**
+   * Signal that the transaction data has been received
+   *
+   * @param updateData
+   */
+  public void signalUpdateReceived(Map<String, Object> updateData) {
+    lock.lock();
+
+    abort = (Boolean) updateData.get("abort");
+    value = updateData.get("value");
+
+    try {
+      if (isReady)
+        throw new IllegalStateException("This transactionUpdateCallback has already been called.");
+      data = updateData;
+      isReady = true;
+      condition.signalAll();
+    } finally {
+      lock.unlock();
+    }
+  }
+
+  /**
+   * Wait for transactionUpdateReceived to signal condition
+   * @throws InterruptedException
+   */
+  void await() throws InterruptedException {
+    lock.lock();
+    Boolean notTimedOut = false;
+
+    try {
+      while (!notTimedOut && !isReady) {
+         notTimedOut = condition.await(30, TimeUnit.SECONDS);
+      }
+    } finally {
+      lock.unlock();
+    }
+  }
+
+  /**
+   * Get the
+   * @return
+   */
+  Map<String, Object> getUpdates() {
+    return data;
+  }
+}