Translating code from Java to JavaScript with the help of the G

Question

Translating code from Java to JavaScript with the help of the G

I am facing a challenge where I need to convert Java code into JavaScript while preserving all method, variable and parameter names. Is it possible to achieve this using the GWT compiler or any other tool available in the market? I attempted compiling the Java code with optimizations turned off, but the method names ended up being mangled. If the GWT compiler cannot handle this task, is there another tool that can do it?

Update

The Java code only relies on GWT emulated classes, making it feasible for the GWT compiler to process.

Update 2

For instance, the Java method :

public String method()

was transformed into this JavaScript function :

function com_client_T_$method__Lcom_client_T_2Ljava_lang_String_2()

with the compilation options :

-style DETAILED
-optimize 0
-draftCompile

Unfortunately, it seems like the names cannot be preserved. Is there a way to control how they get altered?

Clarification

Imagine having a sorting algorithm written in Java that you want to convert into JavaScript without changing the method name, or at least altering it predictably for seamless conversion between the two languages. This would enable you to reuse code across different applications effortlessly even if updates are made to the original Java version. Can this be done with tools like GWT compiler?

Conclusion

The response to the main query is NO. While some method names may be preserved, their functionality cannot be maintained. The scattered nature of method calls within the generated file makes them unsuitable for use in a JavaScript library, which defeats the purpose of the initial objective.

java javascript gwt

Answer 1

Answer №1

Even though it's possible to set the compiler to generate 'pretty' code, I recommend creating export functions for the classes you want to access from outside your GWT project. While there may be documentation on how to do this in GWT, I couldn't locate it, so here is an example that I just came up with.

class YourClass {
    public YourClass() {
        ...
    }

    public void yourMethod() {
        ...
    }

    public static YourClass create() {
        return new YourClass();
    }

    public final static native void export() /*-{
          $wnd.YourClass = function() {
              this.instance = new @your.package.name.YourClass::create()()
          }

          var _ = $wnd.YourClass.prototype;
          _.yourMethod = function() {<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="06726e6f75286f6875726768656328467f697374287667656d6761632868676b63285f697374456a677575">[email protected]</a>::yourMethod();}
    }-*/;
}

UPDATE

To clarify, although your code will undergo obfuscation as usual, you can easily reference those functions externally thanks to the export function. You don't need to rewrite anything from your Java class in JavaScript. Simply write the references in JavaScript, like this:

var myInstance = new YourClass();
myInstance.yourMethod();

Remember to invoke the static export method somewhere in your GWT app (most likely in your EntryPoint) to enable this functionality.

For more information on referencing Java methods from JavaScript: http://code.google.com/webtoolkit/doc/latest/DevGuideCodingBasicsJSNI.html#methods-fields

Answer 2

Even though it's possible to set the compiler to generate 'pretty' code, I recommend creating export functions for the classes you want to access from outside your GWT project. While there may be documentation on how to do this in GWT, I couldn't locate it, so here is an example that I just came up with.

class YourClass {
    public YourClass() {
        ...
    }

    public void yourMethod() {
        ...
    }

    public static YourClass create() {
        return new YourClass();
    }

    public final static native void export() /*-{
          $wnd.YourClass = function() {
              this.instance = new @your.package.name.YourClass::create()()
          }

          var _ = $wnd.YourClass.prototype;
          _.yourMethod = function() {<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="06726e6f75286f6875726768656328467f697374287667656d6761632868676b63285f697374456a677575">[email protected]</a>::yourMethod();}
    }-*/;
}

UPDATE

To clarify, although your code will undergo obfuscation as usual, you can easily reference those functions externally thanks to the export function. You don't need to rewrite anything from your Java class in JavaScript. Simply write the references in JavaScript, like this:

var myInstance = new YourClass();
myInstance.yourMethod();

Remember to invoke the static export method somewhere in your GWT app (most likely in your EntryPoint) to enable this functionality.

For more information on referencing Java methods from JavaScript: http://code.google.com/webtoolkit/doc/latest/DevGuideCodingBasicsJSNI.html#methods-fields

Answer 3

Answer №2

~~Unfortunately, the GWT compiler does not allow for this type of customization as it is specifically designed to generate highly optimized and efficient JavaScript from Java code.~~

One major advantage of using GWT is that you can develop your project in Java and then compile it into JavaScript. This means you can focus on writing and maintaining code in Java without needing to worry about modifying variable or method names in the resulting JavaScript output.

Attempting to modify the JavaScript output directly from GWT can be quite challenging and time-consuming.

Update:

Thanks to a tip from David, I discovered the Compiler Option "-style". You may want to experiment with the following options:

-style=PRETTY -optimize=0

I cannot guarantee if this will produce easily readable code, as the GWT framework will still be embedded in the final JavaScript output making it difficult to make manual changes. Give it a try and share your results with us!

Answer 4

~~Unfortunately, the GWT compiler does not allow for this type of customization as it is specifically designed to generate highly optimized and efficient JavaScript from Java code.~~

One major advantage of using GWT is that you can develop your project in Java and then compile it into JavaScript. This means you can focus on writing and maintaining code in Java without needing to worry about modifying variable or method names in the resulting JavaScript output.

Attempting to modify the JavaScript output directly from GWT can be quite challenging and time-consuming.

Update:

Thanks to a tip from David, I discovered the Compiler Option "-style". You may want to experiment with the following options:

-style=PRETTY -optimize=0

I cannot guarantee if this will produce easily readable code, as the GWT framework will still be embedded in the final JavaScript output making it difficult to make manual changes. Give it a try and share your results with us!

Answer 5

Answer №3

Allow me to shed some light on your second inquiry: "If GWT compiler is unable to achieve this, is there another tool that can?"

Personally, I have been utilizing Java2Script for a considerable amount of time now, even on extensive projects. The integration with native JavaScript works smoothly, the names are maintained, and over time, it becomes relatively easy to correlate the generated JavaScript (observed in the browser debugger) with the original Java code.

Regards, Udo

Answer 6

Allow me to shed some light on your second inquiry: "If GWT compiler is unable to achieve this, is there another tool that can?"

Personally, I have been utilizing Java2Script for a considerable amount of time now, even on extensive projects. The integration with native JavaScript works smoothly, the names are maintained, and over time, it becomes relatively easy to correlate the generated JavaScript (observed in the browser debugger) with the original Java code.

Regards, Udo

Answer 7

Answer №4

If you want to make your function accessible outside of its current scope, one way is to use inline JavaScript that calls it directly. There's also a handy tool called gwt-exporter which automates this process when you add annotations like @Export to your classes and methods. For more details, check out: https://code.google.com/p/gwtchismes/wiki/Tutorial_ExportingGwtLibrariesToJavascript_en

Answer 8

If you want to make your function accessible outside of its current scope, one way is to use inline JavaScript that calls it directly. There's also a handy tool called gwt-exporter which automates this process when you add annotations like @Export to your classes and methods. For more details, check out: https://code.google.com/p/gwtchismes/wiki/Tutorial_ExportingGwtLibrariesToJavascript_en

Translating code from Java to JavaScript with the help of the G

Answer №1

Answer №2

Answer №3

Answer №4

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