Java JSTP implementation

jstp js

Check for the latest JSTP version

Installation

Gradle:

Add this to your build.gradle (check for the latest version):

dependencies {
  compile group: 'com.metarhia.jstp', name: 'jstp', version: '0.10.0'
}

Maven:

<dependency>
  <groupId>com.metarhia.jstp</groupId>
  <artifactId>jstp</artifactId>
  <version>0.10.0</version>
  <type>pom</type>
</dependency>

Parser usage

JSParser will mostly convert to native java objects (with a few exceptions where specific implementation was needed)

Few simple examples

JSObject a = JSParser.parse("{a: 3, b: 2}");
// Get field 'a' of object {a: 3, b: 2}
a.get("a"); // returns 3

// Get second field of object {a: 3, b: 2}
a.getByIndex(1); // returns 2

// But you can easily use it as a Map
Map<String, Number> map = (Map<String, Number>) a;
// or
Map<String, Number> a = JSParser.parse("{a: 3, b: 2}");


List<Double> arr = JSParser.parse("[1, 2, 3]");
// Get second element of array [1, 2, 3];
arr.get(1); // returns 2


String str = JSParser.parse("'abc'");
// str now equals to "abc"


List<?> arr = JSParser.parse("[1,, 3]");
// Get second element of array [1,, 3];
arr.get(1); // returns JSUndefined

To serialize objects you can use JSSerializer

List<Number> arr = new JSNativeParser("[1, 2, 3]").parse();
JSSerializer.stringify(arr); // returns "[1,2,3]"


Map<String, Number> a = JSParser.parse("{a: 3, b: 2}");
JSSerializer.stringify(a); // returns "{a:3,b:2}"

If it doesn't know how to serialize input it'll be serialized as "undefined", also you can define how your objects will be serialized via JSSerializable interface.

They can be parsed in js with a simple eval statement or jstp and mdsf

Connection

Establish connection

To establish JSTP connection, you need to provide transport. As of now the only available transport is TCP. Optionally you can define session policy (there are 2 basic ones in SDK: DropSessionPolicy - which will create new connection every time transport is restored and SimpleSessionPolicy - which will resend cached messages and try to restore session. SimpleSessionPolicy is used by default). For example:

String host = "metarhia.com";
int port = 80;

Transport transport = new TCPTransport(host, port /*, useSSl == true */);
Connection connection = new Connection(transport);

You can change used transport by calling useTransport() method. This will close previous transport if available and set provided one as current transport. It will try to connect and upon connection appropriate method of session policy will be called when transport reports that it's connected.

To react to connection events, you can use ConnectionListener (there is also SimpleConnectionListener version that defaults to ignoring all calls):

connection.addListener(new ConnectionListener() {

  @Override
  public void onConnected(boolean restored) {
    // ...
  }

  @Override
  public void onConnectionClosed() {
    // ...
  }

  @Override
  public void onMessageRejected(JSObject message) {
    // ...
  }
});

You can define applicationName and/or session Id when connecting, or connect without them (you must at least once call connect with application name before that):

connection.connect();
// ...
connection.connect("applicationName");
// ...
connection.connect("applicationName", "sessionId");

JSTP message types

Handshake

Usually you don't have to send handshake messages manually. You may need them if If you need to implement your own session policy or change transport on active connection. You can send handshake message as follows:

// anonymous handshake message
connection.handshake("applicationName", new ManualHandler() {

  @Override
  public void onMessage(JSObject message) {
    // ...
  }

  @Override
  public void onError(int errorCode) {
    // ...
  }
});

// handshake with attempt to restore session "sessionId"
connection.handshake("applicationName", "sessionId", new ManualHandler() {

  @Override
  public void onMessage(JSObject message) {
    // ...
  }

  @Override
  public void onError(int errorCode) {
    // ...
  }
});

// handshake message with authorization (login and password)
connection.handshake("applicationName", "name", "pass", new ManualHandler() {

  @Override
  public void onMessage(JSObject message) {
    // ...
  }

  @Override
  public void onError(int errorCode) {
    // ...
  }
});

Call

To send call message:

List<?> args = Arrays.asList('a', 'b', 'c');
connection.call("interfaceName", "methodName", args, new ManualHandler() {

  @Override
  public void onMessage(JSObject message) {
    // ...
  }

  @Override
  public void onError(int errorCode) {
    // ...
  }
);

Or you can use OkErrorHandler that will make this much simpler and clearer:

List<?> args = Arrays.asList('a', 'b', 'c');
connection.call("interfaceName", "methodName", args, new OkErrorHandler() {

  @Override
  public void handleOk(List<?> data) {
    // ...
  }

  @Override
  public void handleError(Integer errorCode, List<?> data) {
    // ...
  }
);

To handle incoming call messages, you have to set setCallHandler() for that call. There can only be one call handler for each call.

Callback

While sending callback you should specify callback type (JSCallback.OK or JSCallback.ERROR) and arbitrary arguments.

connection.setCallHandler("interfaceName", "methodName", new CallHandler() {

  @Override
  public void handleCall(String methodName, List<?> data) {
    // ...
    callback(connection, JSCallback.OK, Arrays.asList('Hello'));
  }
});

You also can send callback messages like this:

connection.callback(JSCallback.OK, args);

// define custom message number
Long customIndex;
// ...
connection.callback(JSCallback.OK, args, customIndex);

Inspect

Incoming inspect messages are handled by the Connection itself. To make methods visible through inspect message you just need to define method names with appropriate interfaces.

connection.setClientMethodNames("interfaceName1", "methodName1", "methodName2");
connection.setClientMethodNames("interfaceName2", "methodName1", "methodName2");
// ...

To send inspect message:

connection.inspect("interfaceName", new ManualHandler() {

  @Override
  public void onMessage(JSObject message) {
    // ...
  }

  @Override
  public void onError(int errorCode) {
    // ...
  }
});

Event

To handle incoming events, you add event handlers with addEventHandler(). There can be multiple event handlers for each event.

connection.addEventHandler("interfaceName", "methodName", new EventHandler() {

  @Override
  public void handleEvent(String eventName, List<?> data) {
    // ...
  }
});

Sending event message:

List<String> args = Arrays.asList('Hello');
connection.event("interfaceName", "methodName", args);

Executable handler

If you want to handle incoming packets on a separate thread, you can use ExecutableHandler instead of ManualHandler. It requires Executor to run the packet handling method on it. Incoming message is a protected parameter in ExecutableHandler. You can use it like this:

Connection connection = ...;
Executor executor = ...;
connection.call("interfaceName", "methodName", new ArrayList<>(),
  new ExecutableHandler(executor, new OkErrorHandler() {
    @Override
    public void handleOk(List<?> data) {
      // ...
    }

    @Override
    public void handleError(Integer errorCode, List<?> data) {
      // ...
    }
  })
});

JSTP compiler

JSTP compiler is a nice feature to ease handling of JSTP messages. You can declare interfaces that correspond to specific API or simple call to avoid writing all boilerplate code to get the arguments out of the message. JSTP compiler will parse those at compile time and generate implementations.

Installation

Check for the latest version

Gradle:

dependencies {
  compile group: 'com.metarhia.jstp', name: 'jstp-compiler', version: '0.4.0'
}

Maven:

<dependency>
  <groupId>com.metarhia.jstp</groupId>
  <artifactId>jstp-compiler</artifactId>
  <version>0.4.0</version>
  <type>pom</type>
</dependency>

Be aware that compiler documentation is currently outdated and needs a refresh as some methods/usages have changed.

Handlers usage

JSTP handlers are used to process data from incoming JSTP messages, just like usual ManualHandlers do. Unlike ManualHandler, you are able to customize JSTP handlers as you wish, declaring methods with annotations described below. To create your own handler, just add the @Handler annotation to the required interface.

@Handler
public interface ExampleHandler {
  // ...
}

You also can make your handler extended from ManualHandler or ExecutableHandler setting base class as an annotation parameter. For example, if you want the messages to be handled on a separate thread, you can set ExecutableHandler.class as a @Handler parameter:

@Handler(ExecutableHandler.class)
public interface ExampleHandler {
  // ...
}

With this annotation the generated class will respect ExecutableHandler interface and generate its code in run() method instead of handle() method.

@NotNull

Annotates that the method should only be called if all of its arguments are not null (in case of method-wide annotation) or only specific parameters are not null (in case of argument-wide annotations)

@Handler
public interface ExampleHandler {
  // ...
  @NotNull
  void onExampleValue(List<?> args);
  // ...
}

@Object

Gets the field of the received message by specified name. It also allows getting elements from nested objects, the value will be retrieved in the order of keys specified.

@Handler
public interface OkErrorHandler {
  // ...
  @NotNull
  @Object("ok")
  void onOK(List<?> args);

  @NotNull
  @Object("error")
  void onError(List<?> args);

  // gets String value by key "neededValue" in object got by "ok"
  @Object({"ok", "neededValue"})
  void onNeededValueRetrieved(String value);
  // ...
}

@Array

Can be used to get the specific value from JSTP message. It also allows getting elements from nested arrays, the value will be retrieved in the order of indexes specified.

@Handler
public interface ExampleHandler {
  // ...
  void onFirstIndex(@Array(1) String arg);

  // gets (List<?>) message[1][2]
   void onValueBySecondIndex(@Array({1, 2}) List<?> args);
  // ...
}

@Mixed

It is a sort of combination of @Object and @Array annotations. You can get needed value by index or by key. It also allows getting elements from nested objects and arrays, the value will be retrieved in the order of keys and indexes specified. To get a value by key, you should just declare the required key like in @Object annotation, for example "some key". To get value from array by index, you can declare it as "[index]". To get an object value by index (according to keys order) you should declare it as "{key index}".

@Handler
public interface ExampleHandler {
  // ...

  @Mixed("ok")
  void onNeededNamedValue(Object args);

  @Mixed("{1}")
  void onKeyByIndexValue(Object args);

  // gets message["ok"][1][2]
  @Mixed({"ok", "[1]", "{2}"})
  void onNeededMixValue(Object args);
  // ...
}

You can use @Array, @Object, @Mixed annotations with both methods and parameters. In case of method it'll decide starting value to get from (to apply getters) for other parameter-wide getters. If no method-wide getter is specified the value under second key of object'll be used by default, to cancel this behaviour you can either define you own getter or specify @NoDefaultGet annotation (this way starting value'll be the jstp message itself).

After compilation class named like JSTP + (YourHandlerName) (for this example it will be JSTPExampleHandler) will be generated and you will be able to use it in message processing.

connection.call("interfaceName", "methodName", args, new ExampleHandler() {
    // ...
});

JSTP Receivers

You can process received values not only via single handler, but by several ones. They can be added or removed from Receiver via addHandler() and removeHandler() methods. JSTP receiver is generated similarly to Handler. To generate receiver, you need to do the following:

@Receiver
public interface ExampleReceiver {
  // ...
}

The syntax of declaring methods is the same as in Handler. After compilation class named like JSTP + (Your receiver name) (for this example it will be JSTPExampleReceiver) will be generated and you will be able to use it in message processing.

You can use custom receiver like this:

JSTPExampleReceiver receiver = new JSTPExampleReceiver();
receiver.addHandler(new ExampleReceiver() {
    // ...
});
receiver.addHandler(new ExampleReceiver() {
    // ...
});
connection.call("interfaceName", "methodName", args, receiver);

@Proxy

@Proxy annotation allows you to easily auto-generate interface to the remote server that will look as if you are calling local java methods. To create a proxy, you just need to describe the interface with appropriate annotations.

To declare the proxy interface, you need to add the @Proxy annotation to the interface definition. If you want your proxy to be a singleton, set the singleton parameter of the annotation to true. If you want to set the default interface name for the Connection methods, you can set it with interfaceName parameter.

// Creates singleton proxy with default interface name "defaultInterface"
@Proxy(interfaceName = "defaultInterface", singleton = true)
public interface MyProxy {
  // proxy methods
}

For now, you can declare proxy wrappers for sending call and event packets.

Call

To create wrapper for call method, use @Call annotation. Set the method name as an annotation parameter (the default interface will be used), or interface name and method name. The method name is not required as well: if you use @Call annotation without parameters at all, your Java method name will be used as a call method name. Specify the arguments and callback handler (if they are needed) as your method parameters. See the examples:

@Proxy(interfaceName = "defaultInterface")
public interface MyProxy {
  // Makes a call with specified "interfaceName" and "methodName", sets "param"
  // and "otherParam" as call arguments and uses "hander" to handle method
  // callback
  @Call({"interfaceName", "methodName"})
  void callInterfaceMethod(String param, int otherParam, ManualHandler handler);

  // Makes a call with default interface name and method name "methodName"
  // without arguments and uses "hander" to handle method callback
  @Call("methodName")
  void callDefaultInterfaceMethod(ManualHandler handler);

  // Makes a call with default interface name and method name "otherMethodName"
  // without arguments and without callback handler
  @Call("otherMethodName")
  void callNoParametersMethod();

  // Makes a call with default interface name and method name joinChat
  // without arguments and uses handler to handle method callback
  @Call()
  void joinChat(ManualHandler handler);
}

Event

To create wrapper for event method, use @Event annotation. Set the method name as an annotation parameter (the default interface will be used), or interface name and method name. The event name is not required as well: if you use @Event annotation without parameters at all, your Java method name will be used as an event name. Specify the arguments (if they are needed) as your method parameters. See the examples:

@Proxy(interfaceName = "defaultInterface")
public interface MyProxy {
  // Sends event with specified interface name "interfaceName" and event name
  // "eventName" without parameters
  @Event({"interfaceName", "eventName"})
  void sendInterfaceEvent();

  // Sends event with default interface name and event name "eventName" with
  // specified parameters
  @Event("eventName")
  void sendEvent(String param);

  // Sends event with default interface name and event name
  // onSomethingHappened without parameters
  @Event()
  void onSomethingHappened();
}

After compilation class named like JSTP + (Your proxy name) (for this example it will be JSTPMyProxy) will be generated. See some usage examples:

Connection connection;
Executor executor;
// ...
JSTPMyProxy proxy = new JSTPMyProxy(connection);
// calls method and handles callback by manual handler
proxy.callDefaultInterfaceMethod(new ManualHandler() {
    @Override
    public void handle(JSObject jsObject) {
        // handle result
    }
});

// calls method and handles callback by handler created with @Handler annotation
// (see the example of generating handlers)
proxy.callDefaultInterfaceMethod(new JSTPOkErrorHandler() {
    @Override
    public void onOk(List<?> args) {
        // handle data
    }

    @Override
    public void onError(Integer errorCode) {
        // handle error code
    }
});

// calls method and handles callback by executable handler (see the example of
// executable handler)
proxy.callDefaultInterfaceMethod(new ExecutableHandler(executor) {
    @Override
    public void run() {
        // handle message received
    }
});

// sends event with specified parameters
proxy.sendEvent("myParam");

Call handler

You can process incoming call packets by setting call handlers for called methods, just like if you did it with Connection directly. You can set call handler by setCallHandler() method, and remove your handler by removeCallHandler() method. See the examples:

// sets manual call handler for "methodName" of "interfaceName"
proxy.setCallHandler("interfaceName", "methodName", new ManualHandler() {
    @Override
    public void handle(JSObject jsObject) {
        // handle object
    }
});

// sets executable call handler for "methodName" of "interfaceName" (see the
// example of executable handler)
proxy.setCallHandler("interfaceName", "methodName",
        new ExecutableHandler(executor) {
    @Override
    public void run() {
        // handle message received
    }
});

If we want to use handler created with @Handler annotation like this

@Handler
public interface OkErrorHandler {

    @NotNull
    @Object("ok")
    void onOk(List<?> args);

    @NotNull
    @Object("error")
    void onError(@Array(0) Integer errorCode);
}

We can use generated JSTPOkErrorHandler as a call handler for proxy:

proxy.setCallHandler("interfaceName", "methodName", new JSTPOkErrorHandler() {
    @Override
    public void onOk(List<?> args) {
        // handle data
    }

    @Override
    public void onError(Integer errorCode) {
        // handle error code
    }
});

Event handler

You can process incoming event packets by adding event handlers, just like if you did it with Connection directly. You can add event handler by addEventHandler() method, and remove your handler by removeEventHandler() method. See the examples:

// adds manual event handler for "eventName" of "interfaceName"
proxy.addEventHandler("interfaceName", "eventName", new ManualHandler() {
    @Override
    public void handle(JSObject jsObject) {
        // handle object
    }
});

// adds executable handler for "eventName" of "interfaceName" (see the example
// of executable handler)
proxy.addEventHandler("interfaceName", "eventName",
        new ExecutableHandler(executor) {
    @Override
    public void run() {
        // handle message received
    }
});

If we want to use handler created with @Handler annotation like this

@Handler
public interface EventHandler {

    @Object("onMessage")
    void onMessage(@Array(0) String receivedMessage);
}

We can use generated JSTPEventHandler as an event handler for proxy:

proxy.addEventHandler("interfaceName", "eventName", new JSTPEventHandler() {
    @Override
    public void onMessage(String receivedMessage) {
        // handle message
    }
});

If we modify the annotation in such a way:

@Handler(ExecutableHandler.class)
public interface EventHandler {

    @Object("onMessage")
    void onMessage(@Array(0) String receivedMessage);
}

We can use handler with preferred executor:

Executor executor;

// ...

proxy.addEventHandler("interfaceName", "eventName",
        new JSTPEventHandler(executor) {
    @Override
    public void onMessage(String receivedMessage) {
        // handle message
    }
});