composition

问题 As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance. Closed 7 years ago . I know the question has been discussed before, but it seems always under the assumption that inheritance is at least sometimes

问题 As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance. Closed 7 years ago . I know the question has been discussed before, but it seems always under the assumption that inheritance is at least sometimes

问题 I have a <ui:composition> that contains a few elements with explicit ids and some ajax events which reference these ids for partial processing/updating. I encapsulated this fragment of xhtml inside the composition simply so I could use it in a few different places without having to duplicate the code. However, when I use the composition (with <ui:include> ) more than once inside a page, I get duplicate id exceptions. It seems JSF is not wrapping each composition inside its own naming

问题 I can't seem to find a decent answer on the interwebs, though I'm sure it's been asked before. Basically, I have an object that is composed of another object - so black diamond and line. When the parent dies, the object it composes dies. However, the object that is it composed of has a pointer back to the parent. What does this look like in UML? EDIT: For example, a building may be composed of rooms, but the rooms contain pointers back to the building object Thanks 回答1: You would use the

问题 I try to use composition with pandas.DataFrame in the following way, but it is giving me errors when I try to copy the object. import numpy as np import pandas as pd import copy class Foo(object): """ Foo is composed mostly of a pd.DataFrame, and behaves like it too. """ def __init__(self, df, attr_custom): self._ = df self.attr_custom = attr_custom # the following code allows Foo objects to behave like pd.DataFame, # and I want to keep this behavior. def __getattr__(self, attr): return

问题 I am reading the book effective java by Joshua Bloch. on the item 16 of "favor composition over inheritance", he gives an example of using HashSet and querying how many elements have been added since it was created(not to be confused with current size, which goes down when an element is removed). he provided the following code and here the getAddCount return 6, which I can understand. This should return 3 actually. (this is because HashSet's addAll method is implemented on top of its add

问题 I've used the first two videos in this series to learn about some basic OOP concepts. Lately, I primarily write in Node, so I'm working with prototypical inheritance on the front-end and back-end. However, these tutorials showcase OOP concepts with Java. Java is a strictly-typed language which utilizes classical inheritance . This question pertains to both classical and prototypical inheritance, but in different ways. This problem is a little bit difficult to put into words, so I'll use an

问题 It is common knowledge that when we want to "extend" a <Component> in React, we don't actually extend its class via inheritance, but use composition to render it with custom props inside our "derived" component, like this: class Component extends React.Component { render() { return (<div className={ this.props.special_prop }> I'm a component! </div>); } } class DerivedComponent extends React.Component { render() { return (<Component special_prop='custom value' />); } } So this will create a

问题 I am trying to solve subsets from the USACO training gateway... Problem Statement For many sets of consecutive integers from 1 through N (1 <= N <= 39), one can partition the set into two sets whose sums are identical. For example, if N=3, one can partition the set {1, 2, 3} in one way so that the sums of both subsets are identical: {3} and {1,2} This counts as a single partitioning (i.e., reversing the order counts as the same partitioning and thus does not increase the count of partitions).

问题 So I'm trying to build an app that has two different kind of users, namely customers and sellers. The app is designed in such a way that both of them will have different kind of navigation bars and access to different kind of pages via routes. As such, I'm trying to see what is the best way to achieve this? I'm thinking of either of the following solutions: 1. using compose binding or areas in my shell.html and by having a container and based on a certain condition, the correct specific view