FR: Support Automatic Function Calling (AFC) with non-static instance methods

[vorburger]

Is your feature request related to a problem? Please describe.*

It would be neat if we made it possible for Automatic Function Calling (AFC) to also work with non-static instance methods, so that (something like) this would work, note how getCurrentWeather is not static here:

public class GenerateContentWithFunctionCall {
  public String getCurrentWeather(String location, String unit) {
    return "The weather in " + location + " is " + "very nice.";
  }

  public static void main(String[] args) throws NoSuchMethodException {
    GenerateContentWithFunctionCall instance = new GenerateContentWithFunctionCall();

    Method method =
        GenerateContentWithFunctionCall.class.getMethod(
            "getCurrentWeather", String.class, String.class);

    GenerateContentConfig config =
        GenerateContentConfig.builder()
            .tools(Tool.builder().functions(method, instance))
            .build();

[hemasekhar-p]

Hi @vorburger, Thank you for raising this feature request. The current SDK design strictly requires public static methods for AFC, preventing the use of stateful tools. we'll be filing a feature request internally to track it.

[haifengl]

This is critical to build agentic applications with local tool calling. Instead of (static or not) method, an alternative is to take class with JSON annotations on both class (for tool description) and fields (for tool call parameters). Instead of calling the method directly, the agentic app can convert tool calling info to the corresponding class and optionally inject context information.

[priyanahata]

Hi @haifengl and @vorburger and @hemasekhar-p

we got a little library built on top of this genai java sdk were we support non static methods, tool classess (toolkits) are stateful and have built in serialization / deserialization with kryo so your tool classess can preserve their state across restarts of the application

https://asi.anahata.uno/core.html#toolkits

On this image you can see a sample "toolkit" (a class with methods that are tools for the model)
you can also set permissions for each method and the class with your tools can "augment context" so if your class is stateful, anything you want from that class can be added as "augmented context" on every turn.

Also, if you look a the code, you will see it has a callback method that gets triggered when the application is restored so the radio can resume playing the station that you were listening to

Our library also supports context propagation (thread local style), so your tool classess are like Servlets or EJBs, you can call one tool from another tool and access a number of attribute maps like you would do in a servlet container (request / session / application), here instead of "request" is called "turn" but from within the tool you can do things like:

public void log(java.lang.String message) - adds logs to the tools response
public void error(java.lang.String message) - adds errors to the tools respons
public void addAttachment(byte[] data, java.lang.String mimeType) - adds attachments to the tools respons
public T getToolkit(java.lang.Class toolkitClass) - gets the instance of another of your stateful tool classess
public java.lang.String getModelId() - the id of the model calling your tool
public java.util.Map getTurnMap() - a hashamp that is turn scoped
public java.util.Map getSessionMap() - a hasmap that is "chat" scoped"
public java.util.Map getAsiContainerMap() - a hasmap for different chats within the same chat group
public java.util.Map getApplicationMap() - a JVM scped hash map

It also has some built in asyn execution so your tools can do work asynchronously in separate threads while propagating the tool context
public java.util.function.Consumer<java.lang.String> getThreadSafeLogger() -
public void runAsync(java.lang.String taskName, java.lang.Runnable task)

It has a Swing inteface that can show you how your tools parameters and returned types can get translated to json schemas. It does Java type to Json Schema conversion and uses swagger @Schema annotations if you want to add additional info for the model regarding your java types. You can also plug in custom jackson modules if any of our java objects needs special handling