Actual function calling in java sample

generativeai/src/main/java/com/google/ai/client/generativeai/type/Tool.kt

@@ -25,7 +25,7 @@ import org.json.JSONObject
  * @param functionDeclarations The set of functions that this tool allows the model access to
  * @param codeExecution This is a flag value to enable Code Execution. Use [CODE_EXECUTION].
  */
-class Tool(
+class Tool @JvmOverloads constructor(
   val functionDeclarations: List<FunctionDeclaration>? = null,
   val codeExecution: JSONObject? = null,
 ) {

samples/src/main/java/com/google/ai/client/generative/samples/java/function_calling.java

@@ -14,24 +14,41 @@
 
 package com.google.ai.client.generative.samples.java;
 
-// Set up your API Key
-// ====================
-//
-// To use the Gemini API, you'll need an API key. To learn more, see
-// the "Set up your API Key section" in the [Gemini API
-// quickstart](https://ai.google.dev/gemini-api/docs/quickstart?lang=android#set-up-api-key).
-
 import static com.google.ai.client.generativeai.type.FunctionDeclarationsKt.defineFunction;
 
 import com.google.ai.client.generativeai.GenerativeModel;
+import com.google.ai.client.generativeai.java.ChatFutures;
 import com.google.ai.client.generativeai.java.GenerativeModelFutures;
 import com.google.ai.client.generativeai.type.Content;
+import com.google.ai.client.generativeai.type.FunctionCallPart;
 import com.google.ai.client.generativeai.type.FunctionDeclaration;
+import com.google.ai.client.generativeai.type.FunctionResponsePart;
+import com.google.ai.client.generativeai.type.GenerateContentResponse;
+import com.google.ai.client.generativeai.type.RequestOptions;
 import com.google.ai.client.generativeai.type.Schema;
+import com.google.ai.client.generativeai.type.Tool;
+import com.google.common.util.concurrent.FutureCallback;
+import com.google.common.util.concurrent.Futures;
+import com.google.common.util.concurrent.ListenableFuture;
 import java.util.Arrays;
+import java.util.concurrent.Executor;
+import java.util.concurrent.Executors;
+import org.json.JSONException;
+import org.json.JSONObject;
+
+// Set up your API Key
+// ====================
+//
+// To use the Gemini API, you'll need an API key. To learn more, see
+// the "Set up your API Key section" in the [Gemini API
+// quickstart](https://ai.google.dev/gemini-api/docs/quickstart?lang=android#set-up-api-key).
 
 class FunctionCalling {
 
+  double multiply(double a, double b) {
+    return a * b;
+  }
+
   void functionCalling() {
     // [START function_calling]
     FunctionDeclaration multiplyDefinition =
@@ -43,27 +60,83 @@ void functionCalling() {
                 Schema.numDouble("b", "Second parameter")),
             /* required */ Arrays.asList("a", "b"));
 
+    Tool tool = new Tool(Arrays.asList(multiplyDefinition), null);
+
     // Specify a Gemini model appropriate for your use case
     GenerativeModel gm =
         new GenerativeModel(
             /* modelName */ "gemini-1.5-flash",
             // Access your API key as a Build Configuration variable (see "Set up your API key"
             // above)
-            /* apiKey */ BuildConfig.apiKey);
+            /* apiKey */ BuildConfig.apiKey,
+            /* generationConfig (optional) */ null,
+            /* safetySettings (optional) */ null,
+            /* requestOptions (optional) */ new RequestOptions(),
+            /* functionDeclarations (optional) */ Arrays.asList(tool));
     GenerativeModelFutures model = GenerativeModelFutures.from(gm);
 
-    // (optional) Create previous chat history for context
+    // Create prompt
     Content.Builder userContentBuilder = new Content.Builder();
     userContentBuilder.setRole("user");
-    userContentBuilder.addText("Hello, I have 2 dogs in my house.");
-    Content userContent = userContentBuilder.build();
+    userContentBuilder.addText(
+        "I have 57 cats, each owns 44 mittens, how many mittens is that in total?");
+    Content userMessage = userContentBuilder.build();
+
+    // For illustrative purposes only. You should use an executor that fits your needs.
+    Executor executor = Executors.newSingleThreadExecutor();
+
+    // Initialize the chat
+    ChatFutures chat = model.startChat();
+
+    // Send the message
+    ListenableFuture<GenerateContentResponse> response = chat.sendMessage(userMessage);
+
+    Futures.addCallback(
+        response,
+        new FutureCallback<GenerateContentResponse>() {
+          @Override
+          public void onSuccess(GenerateContentResponse result) {
+            if (!result.getFunctionCalls().isEmpty()) {
+              handleFunctionCall(result);
+            }
+            if (!result.getText().isEmpty()) {
+              System.out.println(result.getText());
+            }
+          }
+
+          @Override
+          public void onFailure(Throwable t) {
+            t.printStackTrace();
+          }
+
+          private void handleFunctionCall(GenerateContentResponse result) {
+            FunctionCallPart multiplyFunctionCallPart =
+                result.getFunctionCalls().stream()
+                    .filter(fun -> fun.getName().equals("multiply"))
+                    .findFirst()
+                    .get();
+            double a = Double.parseDouble(multiplyFunctionCallPart.getArgs().get("a"));
+            double b = Double.parseDouble(multiplyFunctionCallPart.getArgs().get("b"));
+
+            try {
+              // `multiply(a, b)` is a regular java function defined in another class
+              FunctionResponsePart functionResponsePart =
+                  new FunctionResponsePart(
+                      "multiply", new JSONObject().put("result", multiply(a, b)));
 
-    Content.Builder modelContentBuilder = new Content.Builder();
-    modelContentBuilder.setRole("model");
-    modelContentBuilder.addText("Great to meet you. What would you like to know?");
-    Content modelContent = userContentBuilder.build();
+              // Create prompt
+              Content.Builder functionCallResponse = new Content.Builder();
+              userContentBuilder.setRole("user");
+              userContentBuilder.addPart(functionResponsePart);
+              Content userMessage = userContentBuilder.build();
 
-    // List<Content> history = Arrays.asList(userContent, modelContent);
+              chat.sendMessage(userMessage);
+            } catch (JSONException e) {
+              throw new RuntimeException(e);
+            }
+          }
+        },
+        executor);
 
     // [END function_calling]
   }