observer-pattern

问题 The procedure for sharing data between components in a child-parent relationship is well documented and dealt with straightforwardly in the React docs. What is less obvious is the accepted way of how one shares state and arbitrary data between components that do not share a child-parent relationship. Flux is offered as a solution, and in the past I have rolled my own pub/sub system, but still there seems a great divide among reactjs developers in this arena. RxJS has been offered as a

问题 I would like to have some observable collections/sequences in Python that allow me to listen on change events, like for adding new items or updating items: list = ObservableList(['a','b','c']) list.addChangeListener(lambda new_value: print(new_value)) list.append('a') # => should trigger the attached change listener data_frame = ObservableDataFrame({'x': [1,2,3], 'y':[10,20,30]}) data_frame.addChangeListener(update_dependent_table_cells) # => allows to only update dependent cells instead of a

问题 I would like to have some observable collections/sequences in Python that allow me to listen on change events, like for adding new items or updating items: list = ObservableList(['a','b','c']) list.addChangeListener(lambda new_value: print(new_value)) list.append('a') # => should trigger the attached change listener data_frame = ObservableDataFrame({'x': [1,2,3], 'y':[10,20,30]}) data_frame.addChangeListener(update_dependent_table_cells) # => allows to only update dependent cells instead of a

问题 I would like to have some observable collections/sequences in Python that allow me to listen on change events, like for adding new items or updating items: list = ObservableList(['a','b','c']) list.addChangeListener(lambda new_value: print(new_value)) list.append('a') # => should trigger the attached change listener data_frame = ObservableDataFrame({'x': [1,2,3], 'y':[10,20,30]}) data_frame.addChangeListener(update_dependent_table_cells) # => allows to only update dependent cells instead of a

问题 I was recently asked what is the difference between a callback and an observer in the Observer OO design pattern. My understanding is that callback is any executable code passed as an argument to a function which is called when a specific event happens. It may be implemented in different forms in different programming languages, such as function pointers, anonymous functions and observers/listeners in the object-oriented paradigm. Developers usually implement callback registration

问题 I would like to ask how I should correctly implement observer pattern when I need to achieve something like this: WeatherStation[temperature, humidity ...] and I need to be able to "observe" each attribute independently. So when temperature changes only temperature observers will be notified, when humidity changes only humidity subscribers will be notified. My idea was that I would create some classes like ObservableTemperature and interface TemperatureObserver but I this way I would have to

问题 I would like to ask how I should correctly implement observer pattern when I need to achieve something like this: WeatherStation[temperature, humidity ...] and I need to be able to "observe" each attribute independently. So when temperature changes only temperature observers will be notified, when humidity changes only humidity subscribers will be notified. My idea was that I would create some classes like ObservableTemperature and interface TemperatureObserver but I this way I would have to

来源： https://stackoverflow.com/questions/64116710/observable-subject-event-listener

问题 I'm modelling a situation in wich there are: NotificationBox : the observer list1 , list2 , list3 : the subjects now I would make a piece of diagram in wich using observer pattern describe the fact that each list implement different type of notify() (for example some change in the state of a list need to be notified only to some observer, with some criterion) I made something like: in this case each subject override the notify method in order to notify only some subset of observer depend on

问题 Context: I am trying to implement something like OOP observable pattern in OCaml with using first-class modules. I have a project with a list of modules and want to extend them with observation without changing. To minimize code duplication I created Subject module and plan to use it as a part of the common way (in the project context) for this extending. I declared three module types: OBSERVER: module type OBSERVER = sig type event type t val send : event -> t -> t end OBSERVABLE: module