Generic ValueConverter - grails

I'm trying to register a custom generic value converter but it's not being picked up in the binding process. What can be wrong. It's based on this manual: https://docs.grails.org/latest/guide/theWebLayer.html#dataBinding
When I remove the generics everything works fine.
my generic enum converter:
abstract class EnumValueConverter < T extends Enum > implements ValueConverter {
#Override
boolean canConvert(Object value) {
value instanceof String
}
#Override
Object convert(Object value) {
try {
T.valueOf(value)
} catch (IllegalArgumentException illegalArgumentException) {
throw new IllegalArgumentException("needs to be one of ${T.values()*.name()} but is: $value")
}
}
#Override
Class<?> getTargetType() {
T
}
}
my specific converter:
class SomeEnumValueConverter extends EnumValueConverter<SomeEnum>{}
registartion in resources.groovy:
someEnumValueConverter SomeEnumValueConverter

You can't use a generic in a context like that. If you create an instance of SomeEnumValueConverter and invoke getTargetType() on that instance the return value will be Object, not SomeEnum so the framework doesn't know what type the converter should be used for.
You can override the getTargetType() method in SomeEnumValueConverter and return SomeEnum.

Related

Binding between an Object and a SimpleIntegerProperty

I have a combo box over my GUI in JavaFX.
This Combo Box is composed of a complex type elements :
public class DureeChoiceBoxElement extends ObservableValueBase<DureeChoiceBoxElement> {
private IntegerProperty duree;
#Override
public String toString() {
return duree.get() + " an";
}
}
I want to map (or bind) the selected complex element with my model which contains the simple type :
public class Pel {
private IntegerProperty duree = new SimpleIntegerProperty(1);
public Property<Number> dureeProperty() {
return duree;
}
public void setDuree(Integer duree) {
this.duree.setValue(duree);
}
public Integer getDuree() {
return duree.getValue();
}
}
How to do it ?
I tried in the controller with :
public class PelController {
#FXML
private ChoiceBox<DureeChoiceBoxElement> duree;
//etc..
pel.dureeProperty().bind(createElapsedBindingByBindingsAPI2(duree.getValue()));
/*
* #return an ObjectBinding of immutable TimeElapsed objects for the player
*/
private ObjectBinding<Property<Number>> createElapsedBindingByBindingsAPI2(
final DureeChoiceBoxElement dureeChoiceBoxElement) {
return Bindings.createObjectBinding(new Callable<Property<Number>>() {
#Override
public IntegerProperty call() throws Exception {
return dureeChoiceBoxElement.dureeProperty();
}
}, dureeChoiceBoxElement.dureeProperty());
}
}
But it doesn't work (even not compile). I want to say that "Bind this simple property to this complex Object calling the method I give you through the method named "createElapsedBindingByBindingsAPI2(..)".
It is logical read but I didn't managed to make it works anyway.
That's poor ....
Any help please :).
Example that (obviously) works with legacy code style (Swing coding) :
duree.getSelectionModel().selectedItemProperty().addListener(new ChangeListener<DureeChoiceBoxElement>() {
#Override
public void changed(ObservableValue<? extends DureeChoiceBoxElement> observable,
DureeChoiceBoxElement oldValue, DureeChoiceBoxElement newValue) {
// changement durée
log.debug("Durée sélectionnée : {}", duree.getSelectionModel().getSelectedItem().getDuree());
log.debug("Durée bindée ? : {}", pel.getDuree());
pel.setDuree(duree.getSelectionModel().getSelectedItem().getDuree());
}
});
Like this my model is set to selected item. But it implies some boilerplate code. Any better idea based on high level bindings of JavaFX ?

Google Cloud Dataflow Custom Keys with common functionality

We are using the Dataflow Java SDK and we have an increasing number of custom key classes that are almost the same.
I would like to have them extend a common abstract class however the Dataflow SDK seems to try to instantiate the abstract class causing an InstantiationException.
Caused by: java.lang.RuntimeException: java.lang.InstantiationException
at org.apache.avro.specific.SpecificData.newInstance(SpecificData.java:316)
at org.apache.avro.specific.SpecificData.newRecord(SpecificData.java:332)
at org.apache.avro.generic.GenericDatumReader.readRecord(GenericDatumReader.java:173)
at org.apache.avro.generic.GenericDatumReader.read(GenericDatumReader.java:151)
at org.apache.avro.generic.GenericDatumReader.read(GenericDatumReader.java:142)
at com.google.cloud.dataflow.sdk.coders.AvroCoder.decode(AvroCoder.java:242)
at com.google.cloud.dataflow.sdk.coders.KvCoder.decode(KvCoder.java:97)
at com.google.cloud.dataflow.sdk.coders.KvCoder.decode(KvCoder.java:42)
at com.google.cloud.dataflow.sdk.util.CoderUtils.decodeFromSafeStream(CoderUtils.java:156)
at com.google.cloud.dataflow.sdk.util.CoderUtils.decodeFromByteArray(CoderUtils.java:139)
at com.google.cloud.dataflow.sdk.util.CoderUtils.decodeFromByteArray(CoderUtils.java:133)
at com.google.cloud.dataflow.sdk.util.MutationDetectors$CodedValueMutationDetector.<init>(MutationDetectors.java:108)
at com.google.cloud.dataflow.sdk.util.MutationDetectors.forValueWithCoder(MutationDetectors.java:45)
at com.google.cloud.dataflow.sdk.transforms.ParDo$ImmutabilityCheckingOutputManager.output(ParDo.java:1218)
at com.google.cloud.dataflow.sdk.util.DoFnRunner$DoFnContext.outputWindowedValue(DoFnRunner.java:329)
at com.google.cloud.dataflow.sdk.util.DoFnRunner$DoFnProcessContext.output(DoFnRunner.java:483)
at com.telstra.cdf.rmr.model.pardos.ParDoAbstractCampaignUAKeyExtractor.processElement(ParDoAbstractCampaignUAKeyExtractor.java:5
here is our abstract class,
#DefaultCoder(AvroCoder.class)
public abstract class SuperClassKey {
public SuperClassKey(){}
public abstract double getSomeValue();
}
and this is the sub class
#DefaultCoder(AvroCoder.class)
public class SubClassKey extends SuperClassKey {
public String foo;
public SubClassKey() {
}
public SubClassKey(String foo){
this.foo = foo;
}
#Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
SubClassKey that = (SubClassKey) o;
if (!foo.equals(that.foo)) return false;
return true;
}
#Override
public int hashCode() {
return foo.hashCode();
}
#Override
public double getSomeValue() {
return foo;
}
}
I have also tried using an interface without success.
Is it possible to have a common abstract class or interface between Keys?
The issue is likely from using a PCollection<SuperClassKey> instead of PCollection<SubClassKey>. The PCollection needs to be typed with a concrete class. The coder can be explicitly specified with .setCoder(AvroCoder.of(SubClassKey.class)) if type inference is not sufficient.
In my canse, i changed the Coder class, example:
Before:
AvroIO.parseGenericRecords(RecordConverter::convert)
.withCoder(AvroCoder.of(Struct.class)).from(...)
After:
AvroIO.parseGenericRecords(RecordConverter::convert)
.withCoder(SerializableCoder.of(Struct.class)).from(...)

#override of Dart code

I noticed PetitParserDart has a lot of #override in the code, but I don't know how do they be checked?
I tried IDEA dart-plugin for #override, but it has no effect at all. How can we use #override with Dart?
From #override doc :
An annotation used to mark an instance member (method, field, getter or setter) as overriding an inherited class member. Tools can use this annotation to provide a warning if there is no overridden member.
So, it depends on the tool you use.
In the current Dart Editor(r24275), there's no warning for the following code but it should (it looks like a bug).
import 'package:meta/meta.dart';
class A {
m1() {}
}
class B extends A {
#override m1() {} // no warning because A has a m1()
#override m2() {} // tools should display a warning because A has no m2()
}
The #override annotation is an example of metadata. You can use Mirrors to check for these in code. Here is a simple example that checks if the m1() method in the child class has the #override annotation:
import 'package:meta/meta.dart';
import 'dart:mirrors';
class A {
m1() {}
}
class B extends A {
#override m1() {}
}
void main() {
ClassMirror classMirror = reflectClass(B);
MethodMirror methodMirror = classMirror.methods[const Symbol('m1')];
InstanceMirror instanceMirror = methodMirror.metadata.first;
print(instanceMirror.reflectee); // Instance of '_Override#0x2fa0dc31'
}
it's 2021 . the override it's optional
Use the #override annotation judiciously and only for methods where the superclass is not under the programmer's control, the superclass is in a different library or package, and it is not considered stable. In any case, the use of #override is optional. from dart api https://api.dart.dev/stable/2.10.5/dart-core/override-constant.html
example
Class A {
void say (){
print ('Say something 1') ;
}
}
Class B extends A {
#override
void adds() { // when i don't type the same name of super class function show an
// warning not an error say 'The method doesn't override an inherited
// method.' because it's not same name but when type the same name must be
// overriding
print ('Say something 2 ')
}
Update : the main use of #override is when try to reach abstract method inside abstract class in sub class that inherited to the abstract super class . must use #override to access the abstract method .

AndroidAnnotations in CursorAdapter

I am developing for android using android annotations but I don't unterstand how to use it with CursorAdapters.
There is already a example for BaseAdapters, but if I add #EBean to a class that extents CursorAdapter I get the error message "#EBean annotated element should have a constructor with one parameter max, of type android.content.Context". CursorAdapter already has two constructors.
public class SongInfoAdapter extends CursorAdapter {
...
#Override
public void bindView(View view, Context context, Cursor cursor) {
...
rowData.id.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
itemOnClick(rowData);
}
});
}
public void itemOnClick(RowDataHolder rowData) {
switch(audioPlayer.getPlayingplayer()) {
case AudioPlayer.RIGHT:
case AudioPlayer.NONE:
audioPlayer.load(rowData.songInfo, AudioPlayer.LEFT);
break;
case AudioPlayer.LEFT:
audioPlayer.load(rowData.songInfo, AudioPlayer.RIGHT);
break;
}
}
...
}
AudioPlayer is a class that uses annotations (#EBean), but I can't write
#Bean
AudioPlayer audioPlayer;
because I can't use annotations in this class. How can I use AndroidAnnotations in CursorAdapter?
Many thanks in advance .
Create a constructor that takes one argument, the context.
SongInfoAdapter (Context context) {
super(context, null, FLAG_AUTO_REQUERY);
}
Create an init method and set the cursor for the adapter in init.
public void init(Cursor c) {
this.changeCursor(c);
}
Now you can annotate SongInfoAdapter with #EBean and use annotations.

More than one singleton instance in Guice injector

We got a Jetty/Jersey application. We are converting it to use Guice for DI. The problem: We need more than one instance of a Singleton classes. The catch: The number of instances is determined dynamically from a configuration file. Therefore we cant use annotations for different instances.
final InjectedClass instance = injector.getInstance(InjectedClass.class);
This is the standard syntax of the injector. I need something like
final String key = getKey();
final InjectedClass instance = injector.getInstance(InjectedClass.class, key);
There is a way to get an instance from a Guice Key.class
final InjectedClass instance = injector.getInstance(Key.get(InjectedClass.class, <Annotation>);
but the problem is that I need some dynamic annotation, not predefined one.
You could try to use Provider, or #Provides method that would have map of all instances already created. When the number of instances is reached number defained in config file, you wont create any new instances, instead you return old instance from map.
For example something like this could help you.
public class MyObjectProvider implements Provider<MyObject> {
private final Injector inj;
private int counter;
private final int maxNum = 5;
private List<MyObject> myObjPool = new ArrayList<MyObject>();
#Inject
public MyObjectProvider(Injector inj) {
this.connection = connection;
}
public MyObject get() {
counter = counter+1%maxNum;
if(myObjPool.size()=<maxNum) {
MyObject myobj = inj.getInstance(MyObject.class);
myObjPool.add(myobj);
return myobj;
} else {
return myObjPool.get(counter);
}
}
}
P.S.
I wrote this from my head so maybe it does not compile, this is just an idea.
You can solve this by creating a factory. In my example I have used the guice extension called multibindings
interface InjectedClassFactory {
public InjectedClass get(String key);
}
class InjectedClass {}
class InjectedClassFactoryImpl implements InjectedClassFactory{
private final Map<String, InjectedClass> instances;
#Inject
InjectedClassFactoryImpl(Map<String, InjectedClass> instances) {
this.instances = instances;
}
#Override
public InjectedClass get(String key) {
return instances.get(key);
}
}
class MyModule extends AbstractModule {
#Override
protected void configure() {
MapBinder<String, InjectedClass> mapBinder =
MapBinder.newMapBinder(binder(), String.class, InjectedClass.class);
//read you config file and retrieve the keys
mapBinder.addBinding("key1").to(InjectedClass.class).in(Singleton.class);
mapBinder.addBinding("key2").to(InjectedClass.class).in(Singleton.class);
}
}

Resources