chore: Resolve merge conflicts

Author: lqiu96

java-datastore/google-cloud-datastore/src/main/java/com/google/cloud/datastore/samples/MetricsSample.java

@@ -0,0 +1,72 @@
+/*
+ * Copyright 2026 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.cloud.datastore.samples;
+
+import com.google.cloud.datastore.Datastore;
+import com.google.cloud.datastore.DatastoreOptions;
+import com.google.cloud.datastore.Entity;
+import com.google.cloud.datastore.Key;
+
+/** A simple sample to verify that Datastore metrics are being recorded and exported correctly. */
+public class MetricsSample {
+
+  public static void main(String[] args) throws Exception {
+    String projectId = System.getenv("GOOGLE_CLOUD_PROJECT");
+    if (projectId == null || projectId.isEmpty()) {
+      System.err.println("Error: GOOGLE_CLOUD_PROJECT environment variable is not set.");
+      System.exit(1);
+    }
+
+    System.out.println("Starting MetricsSample for project: " + projectId);
+
+    // Initialize Datastore client with metrics enabled by default.
+    Datastore datastore =
+        DatastoreOptions.newBuilder().setProjectId(projectId).build().getService();
+
+    System.out.println("Executing operations to generate metrics...");
+
+    // 1. Basic Key Lookup
+    Key key = datastore.newKeyFactory().setKind("MetricsTask").newKey("sample-task");
+    datastore.get(key);
+    System.out.println("Performed lookup.");
+
+    // 2. Transactional Read/Write
+    datastore.runInTransaction(
+        tx -> {
+          Entity entity =
+              Entity.newBuilder(key)
+                  .set("description", "Recorded via MetricsSample")
+                  .set("timestamp", System.currentTimeMillis())
+                  .build();
+          tx.put(entity);
+          return null;
+        });
+    System.out.println("Performed transaction.");
+
+    // 3. Batch operation
+    datastore.delete(key);
+    System.out.println("Performed delete.");
+
+    System.out.println("Waiting 65 seconds for metrics to be flushed to Cloud Monitoring...");
+    // PeriodicMetricReader default interval is 60s.
+    Thread.sleep(65000);
+
+    System.out.println("Sample finished. Check the Cloud Monitoring dashboard for:");
+    System.out.println(" - firestore.googleapis.com/internal/client/operation_latency");
+    System.out.println(" - firestore.googleapis.com/internal/client/transaction_latency");
+  }
+}