feat(genai): add model optimizer text generation samples

genai/snippets/pom.xml

@@ -51,7 +51,7 @@
         <dependency>
             <groupId>com.google.genai</groupId>
             <artifactId>google-genai</artifactId>
-            <version>1.10.0</version>
+            <version>1.15.0</version>
         </dependency>
         <dependency>
             <artifactId>junit</artifactId>

genai/snippets/src/main/java/genai/textgeneration/TextGenerationWithRouting.java

@@ -0,0 +1,72 @@
+/*
+ * 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.textgeneration;
+
+// [START googlegenaisdk_textgen_with_routing]
+
+import com.google.genai.Client;
+import com.google.genai.types.Content;
+import com.google.genai.types.GenerateContentConfig;
+import com.google.genai.types.GenerateContentResponse;
+import com.google.genai.types.HttpOptions;
+import com.google.genai.types.ModelSelectionConfig;
+
+public class TextGenerationWithRouting {
+
+  public static void main(String[] args) {
+    // TODO(developer): Replace these variables before running the sample.
+    String promptText = "Why do we have 365 days in a year?";
+    String featureSelectionPreference = "PRIORITIZE_COST";
+
+    String generateContentText = generateContent(promptText, featureSelectionPreference);
+
+    System.out.println("Response: " + generateContentText);
+  }
+
+  // Generates text with text input and routing option
+  public static String generateContent(String promptText, String featureSelectionPreference) {
+
+    // Model name for Model Optimizer
+    String modelName = "model-optimizer-exp-04-09";
+
+    ModelSelectionConfig modelSelectionConfig =
+        ModelSelectionConfig.builder()
+            .featureSelectionPreference(featureSelectionPreference)
+            .build();
+
+    GenerateContentConfig generateContentConfig =
+        GenerateContentConfig.builder().modelSelectionConfig(modelSelectionConfig).build();       
+
+    // 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("us-central1")
+            .vertexAI(true)
+            .httpOptions(HttpOptions.builder().apiVersion("v1beta1").build())
+            .build()) {
+
+      GenerateContentResponse response =
+          client.models.generateContent(modelName, promptText, generateContentConfig);
+
+      System.out.print(response.text());
+
+      return response.text();
+    }
+  }
+}
+// [END googlegenaisdk_textgen_with_routing]

genai/snippets/src/main/java/genai/textgeneration/TextGenerationWithRoutingAndTextStream.java

@@ -0,0 +1,76 @@
+/*
+ * 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.textgeneration;
+
+// [START googlegenaisdk_textgen_with_routing_and_text_stream]
+
+import com.google.genai.Client;
+import com.google.genai.ResponseStream;
+import com.google.genai.types.GenerateContentConfig;
+import com.google.genai.types.GenerateContentResponse;
+import com.google.genai.types.HttpOptions;
+import com.google.genai.types.ModelSelectionConfig;
+
+public class TextGenerationWithRoutingAndTextStream {
+
+  public static void main(String[] args) {
+    // TODO(developer): Replace these variables before running the sample.
+    String promptText = "Why do we have 365 days in a year?";
+    String featureSelectionPreference = "BALANCED";
+
+    String generateContentStreamText = generateContent(promptText, featureSelectionPreference);
+
+    System.out.println("Response: " + generateContentStreamText);
+  }
+
+  // Generates text with text input and routing option
+  public static String generateContent(String promptText, String featureSelectionPreference) {
+
+    // Model name for Model Optimizer
+    String modelName = "model-optimizer-exp-04-09";
+
+    ModelSelectionConfig modelSelectionConfig =
+        ModelSelectionConfig.builder()
+            .featureSelectionPreference(featureSelectionPreference)
+            .build();
+
+    GenerateContentConfig generateContentConfig =
+        GenerateContentConfig.builder().modelSelectionConfig(modelSelectionConfig).build();       
+
+    // 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("us-central1")
+            .vertexAI(true)
+            .httpOptions(HttpOptions.builder().apiVersion("v1beta1").build())
+            .build()) {
+
+      ResponseStream<GenerateContentResponse> response =
+          client.models.generateContentStream(modelName, promptText, generateContentConfig);
+
+      String streamResponse = "";
+
+      for (GenerateContentResponse res : response) {
+        streamResponse += res.text();
+      }
+
+      return streamResponse;
+    }
+  }
+}
+// [END googlegenaisdk_textgen_with_routing_and_text_stream]

genai/snippets/src/test/java/genai/textgeneration/TextGenerationIT.java

@@ -146,4 +146,28 @@ public void testTextGenerationWithYoutubeVideo() {
     String response = TextGenerationWithYoutubeVideo.generateContent(GEMINI_FLASH);
     assertThat(response).isNotEmpty();
   }
+
+  @Test
+  public void testTextGenerationWithRouting() throws IOException {
+    String textPrompt =
+        "What's a good name for a flower shop that specializes in selling bouquets of"
+            + " dried flowers?";
+    String featureSelectionPreference = "PRIORITIZE_COST";
+    String response =
+        TextGenerationWithRouting.generateContent(textPrompt, featureSelectionPreference);
+    assertThat(response).isNotEmpty();
+  }
+
+  @Test
+  public void testTextGenerationWithRoutingAndTextStream() throws IOException {
+    String textPrompt =
+        "What's a good name for a flower shop that specializes in selling bouquets of"
+            + " dried flowers?";
+    String featureSelectionPreference = "PRIORITIZE_COST";
+
+    String response =
+        TextGenerationWithRoutingAndTextStream.generateContent(
+          textPrompt, featureSelectionPreference);
+    assertThat(response).isNotEmpty();
+  } 
 }