Add fs_update_document_increment snippet (GoogleCloudPlatform#1547)

BenWhitehead · web-flow · commit 329f5761779d · 2019-08-14T17:51:27.000-04:00
diff --git a/firestore/src/main/java/com/example/firestore/snippets/ManageDataSnippets.java b/firestore/src/main/java/com/example/firestore/snippets/ManageDataSnippets.java
@@ -35,6 +35,7 @@
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.ExecutionException;
 
 /** Snippets to demonstrate Firestore add, update and delete operations. */
 class ManageDataSnippets {
@@ -426,4 +427,20 @@ void writeBatch() throws Exception {
     }
     // [END fs_write_batch]
   }
+
+  public void updateDocumentIncrement() throws ExecutionException, InterruptedException {
+    final City city = new City();
+    city.setPopulation(100L);
+    db.collection("cities").document("DC").set(city).get();
+
+    // [START fs_update_document_increment]
+    DocumentReference washingtonRef = db.collection("cities").document("DC");
+
+    // Atomically increment the population of the city by 50.
+    final ApiFuture<WriteResult> updateFuture = washingtonRef
+        .update("population", FieldValue.increment(50));
+    // [END fs_update_document_increment]
+    updateFuture.get();
+  }
+
 }
diff --git a/firestore/src/test/java/com/example/firestore/snippets/ManageDataSnippetsIT.java b/firestore/src/test/java/com/example/firestore/snippets/ManageDataSnippetsIT.java
@@ -188,6 +188,16 @@ public void testWriteBatchIsSuccessful() throws Exception {
     assertFalse(document.get().exists());
   }
 
+  @Test
+  public void testUpdateDocumentIncrementSuccessful() throws Exception {
+    manageDataSnippets.updateDocumentIncrement();
+    CollectionReference collection = db.collection("cities");
+    DocumentReference documentReference = collection.document("DC");
+    final DocumentSnapshot data = documentReference.get().get();
+    assertTrue(data.contains("population"));
+    assertEquals((Long) 150L, data.getLong("population"));
+  }
+
   @AfterClass
   public static void tearDown() throws Exception {
     manageDataSnippets.deleteCollection(db.collection("cities"), 10);
