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Build Identifier: File selectedFile = new File("123"); Binding binding = new DataBindingContext().bindValue(SWTObservables.observeText(textControl), PojoObservables.observeValue(selectedFile, "path") new UpdateValueStrategy(UpdateValueStrategy.POLICY_NEVER), new UpdateValueStrategy(UpdateValueStrategy.POLICY_UPDATE)); The binding works only for the first time. The text field shows 123 in the beginning. If selectedFile gets changed and binding.updateModelToTarget(); is being called, the text field doesn't change. I guess, it's because class File doesn't has a setter for the property path. But I have set the UpdateValueStrategy of targetToModel to POLICY_NEVER, so the setter of File#path isn't required at all and no Exception is thrown (if set to POLICY_UPDATE, an exception occurs). I find this misleading, as the UpdateValueStrategy's in both directions suggesting control over this aspect. Reproducible: Always Steps to Reproduce: 1. run example code 2. see details above
Hello Sascha! My apologies for taking so long to respond to this. I hope my response will still be useful to you. What you are missing is that you can't simply reassign a new value to the selectedFile variable and have data binding pick it up. You must store that value in another observable, and then observe the path as a detail of that observable: WritableValue fileObservable = WritableValue.withValueType(File.class); fileObservable.setValue(selectedFile); When a new file is selected, you indicate this by replacing the value held by the WritableValue: fileObservable.setValue(newSelectedFile); Now, to observe the file path, you must observe it as a *detail* of the parent observable, fileObservable: IObservableFile filePathObservable = PojoProperties.value("path").observeDetail(fileObservable); A "detail" observable is an observable that observes a particular detail of the value of the parent observable--in this case, the file observable. The detail we have chosen to observe is the file's path. So every time we stick a new File object in fileObservable, filePathObservable is updated with the path of that file. Hope this helps.
Thanks for the explanation! >WritableValue fileObservable = WritableValue.withValueType(File.class); >fileObservable.setValue(selectedFile); upon changing the file: >fileObservable.setValue(newSelectedFile); Since I still have to catch the event that changes the file, I could simply update the UI element that displays the path with java.io.File. I don't see how this makes my code shorter. Maybe my misunderstanding is to still have a private property java.io.File on the value object instead of just having an IObservableValue that wraps the File object. But this would make the code less readable, I'm afraid. > IObservableFile filePathObservable = > PojoProperties.value("path").observeDetail(fileObservable); This line doesn't work for me, no IBeanValueProperty#observeDetail found and no IObserveFile, yet I understand what you are suggesting.
