feat(genai): add Vertex AI Search tool sample (#10150)

* feat: add new GenAI Vais tool sample

* refactor: change the way the datastore string was consctructed for better readibility

* include mockito in pom and change tool vais test to mock it instead of using an actual datastore

---------

Co-authored-by: Juan Dominguez <jdomin@softserveinc.com>

Author: jdomingr

genai/snippets/pom.xml

@@ -59,6 +59,12 @@
             <scope>test</scope>
             <version>4.13.2</version>
         </dependency>
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-core</artifactId>
+            <version>5.19.0</version>
+            <scope>test</scope>
+        </dependency>
         <dependency>
             <groupId>com.google.truth</groupId>
             <artifactId>truth</artifactId>

genai/snippets/src/main/java/genai/tools/ToolsVaisWithText.java

@@ -0,0 +1,77 @@
+/*
+ * Copyright 2025 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 genai.tools;
+
+// [START googlegenaisdk_tools_vais_with_txt]
+
+import com.google.genai.Client;
+import com.google.genai.types.GenerateContentConfig;
+import com.google.genai.types.GenerateContentResponse;
+import com.google.genai.types.HttpOptions;
+import com.google.genai.types.Retrieval;
+import com.google.genai.types.Tool;
+import com.google.genai.types.VertexAISearch;
+
+public class ToolsVaisWithText {
+
+  public static void main(String[] args) {
+    // TODO(developer): Replace these variables before running the sample.
+    String modelId = "gemini-2.5-flash";
+    // Load Data Store ID from Vertex AI Search
+    // E.g datastoreId =
+    // "projects/project-id/locations/global/collections/default_collection/dataStores/datastore-id"
+    String datastoreId = "your-datastore";
+    generateContent(modelId, datastoreId);
+  }
+
+  // Generates text with Vertex AI Search tool
+  public static String generateContent(String modelId, String datastoreId) {
+    // Initialize client that will be used to send requests. This client only needs to be created
+    // once, and can be reused for multiple requests.
+    try (Client client =
+        Client.builder()
+            .location("global")
+            .vertexAI(true)
+            .httpOptions(HttpOptions.builder().apiVersion("v1").build())
+            .build()) {
+
+      // Set the VertexAI Search tool and the datastore that the model can use to retrieve data from
+      Tool vaisSearchTool =
+          Tool.builder()
+              .retrieval(
+                  Retrieval.builder()
+                      .vertexAiSearch(VertexAISearch.builder().datastore(datastoreId).build())
+                      .build())
+              .build();
+
+      // Create a GenerateContentConfig and set the Vertex AI Search tool
+      GenerateContentConfig contentConfig =
+          GenerateContentConfig.builder().tools(vaisSearchTool).build();
+
+      GenerateContentResponse response =
+          client.models.generateContent(
+              modelId, "How do I make an appointment to renew my driver's license?", contentConfig);
+
+      System.out.print(response.text());
+      // Example response:
+      // The process for making an appointment to renew your driver's license varies depending
+      // on your location. To provide you with the most accurate instructions...
+      return response.text();
+    }
+  }
+}
+// [END googlegenaisdk_tools_vais_with_txt]

genai/snippets/src/test/java/genai/tools/ToolsIT.java

@@ -18,16 +18,31 @@
 
 import static com.google.common.truth.Truth.assertThat;
 import static com.google.common.truth.Truth.assertWithMessage;
-
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.Mockito.RETURNS_SELF;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.mockStatic;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import com.google.genai.Client;
+import com.google.genai.Models;
+import com.google.genai.types.GenerateContentConfig;
+import com.google.genai.types.GenerateContentResponse;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.PrintStream;
+import java.lang.reflect.Field;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.BeforeClass;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.JUnit4;
+import org.mockito.MockedStatic;
+
 
 @RunWith(JUnit4.class)
 public class ToolsIT {
@@ -105,4 +120,42 @@ public void testToolsGoogleSearchWithText() {
     assertThat(response).isNotEmpty();
   }
 
+  @Test
+  public void testToolsVaisWithText() throws NoSuchFieldException, IllegalAccessException {
+    String response = "The process for making an appointment to renew your driver's license"
+            + " varies depending on your location.";
+
+    String datastore =
+            String.format(
+                    "projects/%s/locations/global/collections/default_collection/"
+                            + "dataStores/grounding-test-datastore",
+                    PROJECT_ID);
+
+    Client.Builder mockedBuilder = mock(Client.Builder.class, RETURNS_SELF);
+    Client mockedClient = mock(Client.class);
+    Models mockedModels = mock(Models.class);
+    GenerateContentResponse mockedResponse = mock(GenerateContentResponse.class);
+
+    try (MockedStatic<Client> mockedStatic = mockStatic(Client.class)) {
+      mockedStatic.when(Client::builder).thenReturn(mockedBuilder);
+      when(mockedBuilder.build()).thenReturn(mockedClient);
+
+      // Using reflection because 'models' is a final field and cannot be mockable directly
+      Field field = Client.class.getDeclaredField("models");
+      field.setAccessible(true);
+      field.set(mockedClient, mockedModels);
+
+      when(mockedClient.models.generateContent(
+              anyString(), anyString(), any(GenerateContentConfig.class)))
+          .thenReturn(mockedResponse);
+      when(mockedResponse.text()).thenReturn(response);
+
+      String generatedResponse = ToolsVaisWithText.generateContent(GEMINI_FLASH, datastore);
+
+      verify(mockedClient.models, times(1))
+          .generateContent(anyString(), anyString(), any(GenerateContentConfig.class));
+      assertThat(generatedResponse).isNotEmpty();
+      assertThat(response).isEqualTo(generatedResponse);
+    }
+  }
 }