google / gwteventbinder Goto Github PK

Hi,
I am reading the landing page for this library and found that the URL:
https://github.com/google/gwteventbinder/tree/master/sample/src/sample/client
is broken. It says "page not found"

I use a pattern where events can either only be fired from classes in the same package (constructor is package-private) or events can only be caught by classes in the same package (handler is package private)

This makes it really easy to reason about the program flow and I catch a lot of bugs with this pattern.

Without handlers is it possible to restrict which classes can catch events?

Hi:
Possible to add a interface method in EventBinder like below:

public HandlerRegistration bindEventHandlers(T target, Object source, EventBus eventBus);

So we can take use of EventBus#addHandlerToSource(...)?

I am trying to use the same example and it fails with this error:

 [java]       [ERROR] Line 36: Rebind result 'MyEventBinder' must be a class

Here is a snippet of my code
public class MyPresenter implements MyInterface.Presenter {
...
public MyPresenter(MyView view) {
this.view = view;
}

interface MyEventBinder extends EventBinder<MyPresenter> {}
private static final MyEventBinder eventBinder = GWT.create(MyEventBinder.class);

...

}

Not using full canonical name for implements type will cause issues if the binding code is in different package than the bound code.

Is it possible to use fully qualified name for ContactsPresenter or add import to generated file:
com.google.web.bindery.event.shared.binder.impl.AbstractEventBinder

I want to keep my presenter fully independent from GWT so i don't want to keep AppEventBinder interface in ContactsPresenter

interface AppEventBinder extends EventBinder<ContactsPresenter> {}

Generated ContactsActivity_AppEventBinderImpl:

package test.client.activity;

import com.google.web.bindery.event.shared.binder.EventBinder;
import com.google.web.bindery.event.shared.EventBus;
import com.google.web.bindery.event.shared.binder.GenericEvent;
import com.google.web.bindery.event.shared.binder.impl.GenericEventHandler;
import com.google.web.bindery.event.shared.HandlerRegistration;
import java.util.LinkedList;
import java.util.List;

public class ContactsActivity_AppEventBinderImpl extends com.google.web.bindery.event.shared.binder.impl.AbstractEventBinder<ContactsPresenter> implements ContactsActivity.AppEventBinder {
  protected List<HandlerRegistration> doBindEventHandlers(final test.client.presenter.ContactsPresenter target, EventBus eventBus) {
    List<HandlerRegistration> registrations = new LinkedList<HandlerRegistration>();
    bind(eventBus, registrations, test.client.event.PersonDeletedEvent.class, new GenericEventHandler() {
      public void handleEvent(GenericEvent event) { target.onPersonLoader((test.client.event.PersonDeletedEvent) event); }
    });
    return registrations;
  }
}

thanks

I am getting a JS error from event binder on Safari.

This happens when trying to bind:

(detailed mode compile)

The app in question is hosted here:

http://www.cherokeelessons.com/CherokeeDictionary

The source is here:

https://github.com/mjoyner-vbservices-net/CherokeeDictionary

This is not an issue but a question.
I've a GWT application that uses GIN and gwteventbinder.
I'm writing some unit tests in order to test the client logic so I'm mocking views and services.
In order to run tests faster I'm avoiding GWTTestCase implementation and trying to run the tests as pure Java. In the test env I'm using directly Guice instead of GIN.
Setting up the tests I've issues providing to Guice a binding for the EventBinders because in normal env this is managed by code generators in GWT.
Have you never faced with the problem?

Just looked through the release notes. Looks like in V1.0.2 added support for GWT 2.6. I didn't see any mention of GWT 2.7.

Does this currently support GWT 2.7?

Thanks,
Jake

Hi,

The documentation states in the client project's .gwt.xml one should add

In the git checkout there is no such file. There is only module.gwt.xml
If I copy this to the proper location the compile runs fine.

cd gwteventbinder/
cp eventbinder/src/main/module.gwt.xml eventbinder/src/main/java/com/google/web/bindery/event/EventBinder.gwt.xml

Am I missing something?

Halo,

Is it possible to declare the interface and the eventBinder to a base class and pick the handlers from a child class?

I know it works if I define the @eventhandler in Base and @OverRide in Child.

Is this possible?

public class Base {
interface MyEventBinder extends EventBinder {
}
protected final MyEventBinder eventBinder = GWT.create(MyEventBinder.class);
public Base() {
eventBinder.bindEventHandlers(this, event_bus);
}
}

public class Child extends Base {
@eventhandler
public void onSelectionChangeEvent(SelectionChangeEvent event) {
log.info("event: " + event);
}
}

It doesn't work for me. I suppose the generator magic must have limits.

Vassillis

[INFO] Caused by: java.lang.NoClassDefFoundError: com/google/gwt/dev/util/Preconditions
[INFO]  at com.google.web.bindery.event.gwt.rebind.binder.EventBinderGenerator.getTargetType(EventBinderGenerator.java:73)
[INFO]  at com.google.web.bindery.event.gwt.rebind.binder.EventBinderGenerator.generate(EventBinderGenerator.java:55)
[INFO]  at com.google.gwt.core.ext.IncrementalGenerator.generateNonIncrementally(IncrementalGenerator.java:40)
[INFO]  at com.google.gwt.dev.javac.StandardGeneratorContext.runGeneratorIncrementally(StandardGeneratorContext.java:676)
[INFO]  at com.google.gwt.dev.cfg.RuleGenerateWith.realize(RuleGenerateWith.java:41)
[INFO]  at com.google.gwt.dev.shell.StandardRebindOracle$Rebinder.rebind(StandardRebindOracle.java:79)
[INFO]  at com.google.gwt.dev.shell.StandardRebindOracle.rebind(StandardRebindOracle.java:276)
[INFO]  at com.google.gwt.dev.shell.StandardRebindOracle.rebind(StandardRebindOracle.java:265)
[INFO]  at com.google.gwt.dev.DistillerRebindPermutationOracle.getAllPossibleRebindAnswers(DistillerRebindPermutationOracle.java:91)
[INFO]  at com.google.gwt.dev.jjs.impl.UnifyAst$UnifyVisitor.handleGwtCreate(UnifyAst.java:387)
[INFO]  at com.google.gwt.dev.jjs.impl.UnifyAst$UnifyVisitor.handleMagicMethodCall(UnifyAst.java:465)
[INFO]  at com.google.gwt.dev.jjs.impl.UnifyAst$UnifyVisitor.endVisit(UnifyAst.java:255)
[INFO]  at com.google.gwt.dev.jjs.ast.JMethodCall.traverse(JMethodCall.java:244)
[INFO]  at com.google.gwt.dev.jjs.ast.JModVisitor.traverse(JModVisitor.java:361)
[INFO]  at com.google.gwt.dev.jjs.ast.JModVisitor.accept(JModVisitor.java:273)
[INFO]  ... 48 more
[INFO] Caused by: java.lang.ClassNotFoundException: com.google.gwt.dev.util.Preconditions
[INFO]  at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
[INFO]  at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
[INFO]  at java.security.AccessController.doPrivileged(Native Method)
[INFO]  at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
[INFO]  at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
[INFO]  at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
[INFO]  at java.lang.ClassLoader.loadClass(ClassLoader.java:358)

Because Preconditions class is removed in GWT 2.6
GIN already has fix for this in trunk.

I think an update of gwt's dependency versions should be the only change...
Thanks

According to EventBinderTest, when presenter.handlerRegistration.removeHandler() is called, all handlers are unregistered, regardless of the event's type.

It would be awesome if one could unregister only handlers of a particular event type, e.g.: presenter.handlerRegistration.removeHandler(SecondEvent.class);

Hey there!

I've made some changes to support specifying an @eventhandler for a base, abstract event. The generator just generates an additional bind() call for each subtype (recursively).

This is really great for us because now we can cover entire "classes" of events with just one handler, rather than manually being forced to specify explicit @EventHandlers for each subtype.

Is this something y'all would be interested in? If so, I can tidy things up and send a pull request this week.

Separate compilation is used to speed up SuperDevMode. It compiles each module on its own and fails on EventBinder.gwt.xml because it only inherits com.google.web.bindery.event.Event but uses classes from com.google.gwt.event.EventBase, e.g. class GwtEvent.

To fix that I locally changed EventBinder.gwt.xml to inherit com.google.gwt.event.EventBase. This seems to work although I am not sure if it wouldn't be better to inherit com.google.gwt.user.User instead.

However after doing so, separate compilation complains that the interface com.google.web.bindery.event.shared.binder.EventBinder is provided by two modules: com.google.web.bindery.event.EventBinder and com.google.gwt.user.User. That's probably because gwteventbinder has reused the shared package already provided by com.google.web.bindery.event.Event. Separate compilation requires that each compilation unit is unique to a single GWT module so I think to fix that problem gwteventbinder classes must be moved to its own package.

You can reproduce the issue by creating a sample application using gwt trunk and gwteventbinder. Then start SuperDevMode using -Xincremental.

Hello,

we successfully used the EventBinder in our project. All worked well but we have discovered one disadvantage.
Currently we cannot define a EventHandler in abstract classes which will be extended by our concrete presenter implementations.
This is very awkward.
Our current workaround for this is that we bind the event, which should be normally handled by the abstract class, in our extending presenter implementations and from there we call a method from the abstract class to handle/work with the events context.

Is it possible to bind the event handler methods in the abstract classes after all or do we have to work with our workaround?

With best regards
Marco

There is a transitive dependency on (gwt-user-2.6.0) GWT 2.6.0 when using GRADLE/MAVEN.

workaround:

gwt ('com.google.gwt.eventbinder:eventbinder:1.1.0') {
exclude module: 'gwt-user'
}

It would be nice if one of the examples showed a really simple example of using the HandlerRegistration to remove the handlers on PresentsWidgets.stop(). This is obviously part of the GwtEventBinder API, but isn't demonstrated in the examples.

Ps. I am loving EventBinder! It has saved me a ton of boilerplate. And yes, I figured out the removal of handlers just fine after a few minutes, but it would still be helpful to have in the samples.

It would be nice if generic events were supported. Right now generic events are dispatched based on their type erasure.

My workaround is to create a non-generic subclass and fire that.

When I try to compile my application with GWT 2.6.0-rc1, I get an error:

Caused by: java.lang.NoClassDefFoundError: com/google/gwt/dev/util/Preconditions
at com.google.web.bindery.event.gwt.rebind.binder.EventBinderGenerator.getTargetType(EventBinderGenerator.java:73)

which is because the Preconditions class has been removed from GWT. It's also a problem for GIN according to:
https://code.google.com/p/google-web-toolkit/issues/detail?id=8433
https://groups.google.com/forum/#!topic/Google-Web-Toolkit/O3YYBYkO8t0

Hi,
it seems the current POM forces the 2.6.0 version of GWT when using gwteventbinder, even if the project using this library provides a newer version of GWT (for example, 2.6.1).

I'm no expert on maven (on the contrary), but from what I've seen in other projects (and the Maven docs) the solution is to declare the dependency of those gwt-* dependencies as provided:

<dependency>
  <groupId>com.google.gwt</groupId>
  <artifactId>gwt-dev</artifactId>
  <version>2.6.0</version>
  <scope>provided</scope>
</dependency>
<dependency>
  <groupId>com.google.gwt</groupId>
  <artifactId>gwt-user</artifactId>
  <version>2.6.0</version>
  <scope>provided</scope>
</dependency>

Internal error in the plugin manager executing goal 'net.ltgt.gwt.maven:gwt-maven-plugin:1.0-alpha-2:generate-module': Unable to load the mojo 'net.ltgt.gwt.maven:gwt-maven-plugin:1.0-alpha-2:generate-module' in the plugin 'net.ltgt.gwt.maven:gwt-maven-plugin'. A required class is missing: org/codehaus/plexus/classworlds/realm/DuplicateRealmException
org.codehaus.plexus.classworlds.realm.DuplicateRealmException