I am learning GWT, I am trying following example in which I have tried to pass the JSON object in java function.
public class HomeController implements EntryPoint {
public void onModuleLoad() {
createTestNativeFunction();
Presenter presenter = new PersenterImpl();
presenter.go(RootPanel.get());
}
public native void createTestNativeFunction()/*-{
parser: function() {
var that = this;
var jsonResult = JSON.parse({id:42,name:'yo'});
return this.#com.easylearntutorial.gwt.client.HomeController::onParse(Lorg/sgx/jsutil/client/JsObject;)(jsonResult);
}
void onParse(jsonResult){
System.out.println(jsonResult);
}
}
}-*/;
}
I am getting following errors:
Tracing compile failure path for type 'com.easylearntutorial.gwt.client.HomeController'
[ERROR] Errors in 'file:/C:/Users/ameen/workspace/Tutorial/src/com/easylearntutorial/gwt/client/HomeController.java'
[ERROR] Line 31: missing ; before statement
void onParse(jsonResult){
--------------------------------^
[ERROR] Hint: Check the inheritance chain from your module; it may not be inheriting a required module or a module may not be adding its source path entries properly
[WARN] Server class 'com.google.gwt.dev.shell.jetty.JDBCUnloader' could not be found in the web app, but was found on the system classpath
[WARN] Adding classpath entry 'file:/C:/Program%20Files/gwt-2.7.0/gwt-dev.jar' to the web app classpath for this session
For additional info see: file:/C:/Program%20Files/gwt-2.7.0/doc/helpInfo/webAppClassPath.html
You really should try to avoid JSNI. You can probably write 99% of your code not using JSNI at all. If you really need it, you should use the new JsInterop instead, documentation still in early stage but you can see this documentation here.
If you need to use JsInterop or JSNI it is usually because you need to wrap a JS lib, so first, try to find if it is already wrapped. If it is not you can always use some other wrapper library to learn how to wrap your JS lib.
OpenLayers JsInterop wrapper https://github.com/TDesjardins/gwt-ol3
OpenLayers JSNI wrapper (deprecated) https://github.com/geosdi/GWT-OpenLayers
Or explore github https://github.com/search?q=topic%3Agwt+topic%3Ajsinterop
System.out.println() is a java function, you are looking for console.log().
The body of the native is JavaScript, not Java.
You are declare you variable jsonResult into your parser: function(), jsonResult only exist into that function. Thats why the system say you that
missing ; before statement
Because you never declare the varieble into createTestNativeFunction().
Plus sjakubowski is right System.out.println() is a java function, you need to use console.log() on JavaScript.
Try this:
public native void createTestNativeFunction(){
var jsonResult = {};
parser: function() {
var that = this;
jsonResult = JSON.parse({id:42,name:'yo'});
return this.#com.easylearntutorial.gwt.client.HomeController::onParse(Lorg/sgx/jsutil/client/JsObject;)(jsonResult);
}
void onParse(jsonResult){
console.log(jsonResult);
}
}
I did the following to solve my errors.
public class HomeController implements EntryPoint {
public void onModuleLoad() {
createTestNativeFunction();
Presenter presenter = new PersenterImpl();
presenter.go(RootPanel.get());
}
// var jsonResult = JSON.parse({id:42,name:'yo'});
public native void createTestNativeFunction()/*-{
var that = this;
$wnd.testFunction = function(jsonResult) {
that.#com.easylearntutorial.gwt.client.HomeController::onParse(Lorg/sgx/jsutil/client/JsObject;)(jsonResult);
};
}-*/;
public void onParse(JsObject jsonResult){
int i =42;
}
}
Related
I'm creating a Nativescript plugin. It includes a custom Android Library (AAR) and I want to use it from the Typescript code. When I run a demo (in device or emulator) I get a TypeError: sender.registerListener is not a function error when calling this registerListener method, which is weird because I'm able to call other methods of the same object.
I think that it could be because I am not implementing properly the interface required as parameter. I think that I can explain it better with code:
Sender.java: the public class I will use in Typescript:
package com.berriart.android.myplugin;
public class Sender {
public static final String TAG = "Sender";
private Context _context = null;
public Sender(Context context) {
_context = context;
}
public void send(final String messagePath, final String messageToSend) {
if (Log.isLoggable(TAG, Log.INFO)) {
Log.i(TAG, "Send call: " + messagePath + " " + messageToSend);
}
}
public void registerListener(MessageListener listener) {
if (Log.isLoggable(TAG, Log.INFO)) {
Log.i(TAG, "registerListener");
}
}
// Other code here
}
MessageListener.java: the interface that must be implemented by the registerListener parameter:
package com.berriart.android.myplugin;
public interface MessageListener {
void receive(String messagePath, String messageReceived);
}
This is the Typescript (Nativescript) code of the plugin ( to ):
import * as app from "tns-core-modules/application";
export class WearMessaging {
public static send(messagePath: string, messageToSend: string) {
let sender = new com.berriart.android.myplugin.Sender(app.android.context);
sender.send(messagePath, messageToSend);
}
public static registerListener(receiveCallback: (messagePath: string, messageReceived: string) => void) {
let messageListener = new com.berriart.android.myplugin.MessageListener({
receive: receiveCallback
});
let sender = new com.berriart.android.myplugin.Sender(app.android.context);
sender.registerListener(messageListener);
}
}
If I include WearMessaging.send("/demo", "Hola"); in my nativescript application it compiles and run properly, it's call the Java method successfuly. But if I run:
WearMessaging.registerListener((messagePath: string, messageReceived: string) => {
console.log(messagePath);
console.log(messageReceived);
});
The application stops at run time and throws: TypeError: sender.registerListener is not a function refering to the myplugin.android.ts file.
I'm getting crazy trying to make this work, so, let me know if you have any clue. As I say I think that is because I'm missing something when implementing the interface and because the parameter type do not match them method is not being recognized, but maybe I'm wrong.
Here you can see some official doc:
https://docs.nativescript.org/runtimes/android/generator/extend-class-interface
Thanks in advance.
Ok, I solved it :S
It seems that the incremental build was doing something wrong. After deleting manually the build files of the demo everything went fine:
rm -rf platforms/android/build/*
rm -rf platforms/android/app/build/*
# Then build & deploy again
So, question code seems to be fine if you need to do something similar.
My situation
I call multiple Groovy scripts from Java, they both contain long-lived Groovy objects.
I would like my Groovy scripts to make some changes to a Java meta-class for a Java class (that have about 100 instances). However, the scripts should be able to make different changes, and changes in one of the scripts should not be reflected in the other scripts.
The problem: The meta-class for the Java class is shared across all the scripts.
This question is similar to How do I undo meta class changes after executing GroovyShell? but in this case I want two scripts to execute simultaneously, so it is not possible to reset after script execution.
Example Code
SameTest.java
public interface SameTest {
void print();
void addMyMeta(String name);
void addJavaMeta(String name);
void callMyMeta(String name);
void callJavaMeta(String name);
}
SameSame.java
import groovy.lang.Binding;
import groovy.util.GroovyScriptEngine;
public class SameSame {
public SameTest launchNew() {
try {
GroovyScriptEngine scriptEngine = new GroovyScriptEngine(new String[]{""});
Binding binding = new Binding();
binding.setVariable("objJava", this);
SameTest script = (SameTest) scriptEngine.run("test.groovy", binding);
return script;
} catch (Exception | AssertionError e) {
throw new RuntimeException(e);
}
}
public static void main(String[] args) {
SameSame obj = new SameSame();
SameTest a = obj.launchNew();
SameTest b = obj.launchNew();
a.addMyMeta("a");
a.callMyMeta("a");
try {
b.callMyMeta("a");
throw new AssertionError("Should never happen");
} catch (Exception ex) {
System.out.println("Exception caught: " + ex);
}
a.addJavaMeta("q");
b.callJavaMeta("q");
a.print();
b.print();
}
}
test.groovy
ExpandoMetaClass.enableGlobally()
class Test implements SameTest {
SameSame objJava
void print() {
println 'My meta class is ' + Test.metaClass
println 'Java meta is ' + SameSame.metaClass
}
void addMyMeta(String name) {
println "Adding to Groovy: $this $name"
this.metaClass."$name" << {
"$name works!"
}
}
void addJavaMeta(String name) {
println "Adding to Java: $this $name"
objJava.metaClass."$name" << {
"$name works!"
}
}
void callMyMeta(String name) {
println "Calling Groovy: $this $name..."
"$name"()
println "Calling Groovy: $this $name...DONE!"
}
void callJavaMeta(String name) {
println "Calling Java: $this $name..."
objJava."$name"()
println "Calling Java: $this $name...DONE!"
}
}
new Test(objJava: objJava)
Output
Adding to Groovy: Test#7ee955a8 a
Calling Groovy: Test#7ee955a8 a...
Calling Groovy: Test#7ee955a8 a...DONE!
Calling Groovy: Test#4a22f9e2 a...
Exception caught: groovy.lang.MissingMethodException: No signature of method: Test.a() is applicable for argument types: () values: []
Possible solutions: any(), any(groovy.lang.Closure), is(java.lang.Object), wait(), wait(long), each(groovy.lang.Closure)
Adding to Java: Test#7ee955a8 q
Calling Java: Test#4a22f9e2 q...
Calling Java: Test#4a22f9e2 q...DONE!
My meta class is groovy.lang.ExpandoMetaClass#2145b572[class Test]
Java meta is groovy.lang.ExpandoMetaClass#39529185[class SameSame]
My meta class is groovy.lang.ExpandoMetaClass#72f926e6[class Test]
Java meta is groovy.lang.ExpandoMetaClass#39529185[class SameSame]
Desired result
The two lines showing information about the Java meta should be different.
This should crash:
a.addJavaMeta("q");
b.callJavaMeta("q");
The question
Is it possible somehow to use different MetaClassRegistry's in the different GroovyScriptEngine instances?
Or is there any other way to make the desired result as shown above happen?
The feature you are looking for is one I had planed for Groovy 3. But since I will no longer be able to work full time on Groovy and since nobody else dares a big change to the MOP this is no option at the moment.
So is it possible to use different MetaClassRegistry's in the different GroovyScriptEngine instances?
No, since you cannot use different MetaClassRegistry's. The implementation is somewhat abstracted, but the usage of MetaClassRegistryImpl is hardcoded and allows for only one global version.
Or is there any other way to make the desired result as shown above happen?
That depends on your requirements.
If you could let the scripts not share the Java classes (load them using differing class loaders), then you don't have a problem with shared meta classes to begin with (for those). If you want more the idea bayou.io had might be best.
You could provide your own meta class creation handle (see setMetaClassCreationHandle in MetaClassRegistry). Then you would have to of course capture a call like ExpandoMetaClass.enableGlobally(). You could use ExpandoMetaClass with a custom invoker (set someClass.metaClass.invokeMethod = ...) or of course directly extend the class. You would then somehow need a way to recognize that you are coming from one script or the other (there is something called origin or caller in the bigger invokemethod signature, but the information is not always reliable. Same thing for get/setProperty). As for how to reliably and efficiently transport that information... well.. that's something I have no answer for. You have to experiment if what ExpandoMetaClass provides is good enough for you. Maybe you could use a ThreadLocal to store the information... though then you would have to write a transform, which will rewrite all method and property calls and most probably cause a performance disaster.
I am new to accessing DLLs from Java using JNA. I need to access methods from a class within a DLL(written in .net). Form this sample DLL below, I am trying to get AuditID and Server ID. I am ending with the following error while I am running my code. Any guidance really appreciated.
/// Error ///
Exception in thread "main" java.lang.UnsatisfiedLinkError: Error looking up function 'GetEnrollcontext': The specified procedure could not be found.
//DLL File Code//
SampleDLL.ProfileEnroll enrollcontext = new SampleDLL.ProfileEnroll();
enrollcontext.Url =” url”;
enrollcontext.AuditIdType = SampleDLL.ProfileId;
enrollcontext.AuditId = “22222222 “;
enrollcontext.ServerId = “server1”;
/// Java Code ///
import com.sun.jna.Library;
import com.sun.jna.Native;
import com.sun.jna.Structure;
import dllExtract.DLLExtractTest.SampleDLL.Enrollcontext;
public class SampleDLLExtract {
public interface SampleDLL extends Library {
SampleDLL INSTANCE = (SampleDLL) Native.loadLibrary("SampleDLL",
SampleDLL.class);
public static class Enrollcontext extends Structure {
public String auditId;
public String serverId;
}
void GetEnrollcontext(Enrollcontext ec); // void ();
}
public static void main(String[] args) {
SampleDLL sdll = SampleDLL.INSTANCE;
SampleDLL.Enrollcontext enrollContext = new SampleDLL.Enrollcontext();
sdll.GetEnrollcontext(enrollContext);
System.out.println(sdll.toString(sdll.GetEnrollcontext(enrollContext)));
}
}
in fact there is a solution for you to use C#, VB.NET or F# code via JNA in Java (and nothing else)! and it is also very easy to use:
https://www.nuget.org/packages/UnmanagedExports
with this package all you need to do is, add [RGiesecke.DllExport.DllExport] to your methods like that:
C# .dll Project:
[RGiesecke.DllExport.DllExport]
public static String yourFunction(String yourParameter)
{
return "CSharp String";
}
Java Project:
public interface jna extends Library {
jna INSTANCE = (jna) Native.loadLibrary("yourCSharpProject.dll", jna.class);
public String yourFunction(String yourParameter);
}
use it in the code:
System.out.println(jna.INSTANCE.yourFunction("nothingImportant"));
Viola!
As already mentioned it works very easy, but this solution has some limitations:
only available for simple datatypes as parameter & return values
no MethodOverloading available. yourFunction(String yourParameter) and yourFunction(String yourParameter, String yourSecondParameter) does not work! you have to name them differently
Use arrays as parameter or return values. (JNA offers StringArray, but I am not able to use them in C#) (maybe there is a solution, but I couldn't come up with one so far!)
if you export a method you can't call it internally in your C# code (simple to bypass that by the following:
.
[RGiesecke.DllExport.DllExport]
public static Boolean externalAvailable(String yourParameter)
{
return yourInternalFunction(yourParameter);
}
With C# it works great, with VB.NET and F# I have no experience.
hope this helps!
We have some legacy code with Groovy, and we want to remove Groovy from the application, so, we need to get the java source code generated after using the gmaven plug-in.
Basically, in other words I am dynamically generating new classes (using gmaven Groovy maven plug in) and I would like to be able to obtain the java source code of such generated classes.
I researched a little bit and can see that the only goals for this plug in are
<goal>generateStubs</goal>
<goal>compile</goal>
<goal>generateTestStubs</goal>
<goal>testCompile</goal>
I can't see any goal that allows you to obtain the fully implemented java source code, the stub code is not enough for us as we need the final implementation source code in order to get rid of Groovy.
I'm not very familiar with the gmaven plugin, but I assume it compiles the groovy code into byte code. In this case, you can use a byte code decompiler, there is a nice list here. In the past I've used JAD and it was quite nice. The best ones will also try to create meaningful variable names based on class names.
One warning though - Groovy objects are derived from GObject, not java.lang.Object, so you would probably need to keep the groovy jar until the groovy->java porting is done. Also, be prepared that it won't be a very easy to read java...
It may be out of your scope (1 year old) but I fought against the same problem and found a method to retrieve the algorithm (not the java source code) from the decompiled groovy classes.
You may want to take a look : http://michael.laffargue.fr/blog/2013/11/02/decompiling-groovy-made-classes/
The generated stubs will be useless for you. They are just what their names suggests: stubs.
The stubs are only useful when doing joint java/groovy compilation. That's because there are two compilers involved in a java/groovy mixed project.
Parse groovy
Create stubs
Compile java and stubs (using javac)
Continue groovy compilation (using groovyc)
The groovy code will be compiled using groovyc compiler and the result is byte code.
This is an example of a generated stub:
package maba.groovy;
import java.lang.*;
import java.io.*;
import java.net.*;
import java.util.*;
import groovy.lang.*;
import groovy.util.*;
#groovy.util.logging.Log4j() public class Order
extends java.lang.Object implements
groovy.lang.GroovyObject {
public groovy.lang.MetaClass getMetaClass() { return (groovy.lang.MetaClass)null;}
public void setMetaClass(groovy.lang.MetaClass mc) { }
public java.lang.Object invokeMethod(java.lang.String method, java.lang.Object arguments) { return null;}
public java.lang.Object getProperty(java.lang.String property) { return null;}
public void setProperty(java.lang.String property, java.lang.Object value) { }
public int getPrice() { return (int)0;}
public void setPrice(int value) { }
public int getQuantity() { return (int)0;}
public void setQuantity(int value) { }
#java.lang.Override() public java.lang.String toString() { return (java.lang.String)null;}
}
As you can see there is nothing useful. And you will still depend on some groovy libraries.
This question has been on the mailing-list some time ago [0]. To summarize: Groovy to Java is hard to achieve since there are language constructs and APIs (if you do want to totally remove the Groovy dependency) that are not available in Java.
Especially with the introduction of call-site caching and other performance optimizing techniques the generated Java code would look a lot like this (for the matter of simplicity I just threw some script into JD-GUI [1]):
public class script1351632333660 extends Script
{
public script1351632333660()
{
script1351632333660 this;
CallSite[] arrayOfCallSite = $getCallSiteArray();
}
public script1351632333660(Binding arg1)
{
Binding context;
CallSite[] arrayOfCallSite = $getCallSiteArray();
ScriptBytecodeAdapter.invokeMethodOnSuperN($get$$class$groovy$lang$Script(), this, "setBinding", new Object[] { context });
}
public Object run()
{
CallSite[] arrayOfCallSite = $getCallSiteArray(); Object items = ScriptBytecodeAdapter.createList(new Object[0]);
Object[] item = (Object[])ScriptBytecodeAdapter.castToType(ScriptBytecodeAdapter.createList(new Object[] { "Fluff", arrayOfCallSite[1].callConstructor($get$$class$java$util$Date()), (Integer)DefaultTypeTransformation.box(11235813) }), $get$array$$class$java$lang$Object());
arrayOfCallSite[2].call(items, item);
arrayOfCallSite[3].callCurrent(this, items);
ValueRecorder localValueRecorder = new ValueRecorder();
try
{
Object tmp102_101 = items; localValueRecorder.record(tmp102_101, 8);
Object tmp126_121 = arrayOfCallSite[4].call(tmp102_101, new script1351632333660._run_closure1(this)); localValueRecorder.record(tmp126_121, 14); if (DefaultTypeTransformation.booleanUnbox(tmp126_121)) localValueRecorder.clear(); else ScriptBytecodeAdapter.assertFailed(AssertionRenderer.render("assert items.findAll { it }", localValueRecorder), null); } finally {
localValueRecorder.clear(); throw finally; } return null; return null; }
static { __$swapInit();
Long localLong1 = (Long)DefaultTypeTransformation.box(0L);
__timeStamp__239_neverHappen1351632333665 = localLong1.longValue();
Long localLong2 = (Long)DefaultTypeTransformation.box(1351632333665L);
__timeStamp = localLong2.longValue(); }
class _run_closure1 extends Closure implements GeneratedClosure { public _run_closure1(Object _thisObject) { super(_thisObject); }
public Object doCall(Object it) { CallSite[] arrayOfCallSite = $getCallSiteArray(); return it; return null;
}
// ...
[0] http://groovy.329449.n5.nabble.com/Java-lt-gt-Groovy-converters-td337442.html
[1] http://java.decompiler.free.fr
I'm still pretty new to JSON and GWT and I'm trying to figure out how to pass JSON data back from a page into my GWT app. I pass the JSON back to a class:
public class GetProductTree extends JavaScriptObject {
protected GetProductTree() { }
public final native String getCustomerName() /*-{ return this.customername; }-*/;
}
It's pretty basic and not complete at this moment so I'm just trying (for now) to make sure I can get something back.
The code to call this is:
submitProject.addClickListener(new ClickListener() {
public void onClick(Widget w) {
RequestBuilder.Method method=RequestBuilder.GET;
final String url1 = "http://localhost:8500/getProducts.cfm";
//Window.alert(url1);
RequestBuilder rb = new RequestBuilder(method, url1);
try {
rb.sendRequest(null, new RequestCallback() {
public void onResponseReceived(Request request, Response response) {
JSONObject oResults = (JSONObject) JSONParser.parse(response.getText());
GetProductTree oResponse = oResults.isObject().getJavaScriptObject().cast();
Window.alert(oResponse.getCustomerName());
}
public void onError(Request arg0, Throwable arg1) {
Window.alert("error");
}
});
} catch (RequestException e) {
}
}
});
However I get an error:
No source code is available for type
XYZ.GetProductTree; did
you forget to inherit a required
module?
I am importing the correct package for XYZ.GetProductTree on the call page. What am I missing?
This error is from the compiler, complaining that it can't find that type in it's classpath. For the GWT compiler to find your classes they have to be and in your classpath, and they have to be referenced in a .gwt.xml module file as well. Can you post your package names and the contents of your .gwt.xml files? My guess is that wherever you have put this class it's not visible to the GWT compiler.
I am so obtuse sometimes. I forgot about having to add the source path for my new package. I added this to a "data" package which I just created and didn't add the path to the XML. Thanks :)