DesignPatterns | DesignPatterns samples by csharp on dotnetcore Summary | Architecture library
kandi X-RAY | DesignPatterns Summary
kandi X-RAY | DesignPatterns Summary
DesignPatterns samples by csharp on dotnetcore Summary of design patterns in "Big Talk Design Patterns" / C# (.NET) code
Support
Quality
Security
License
Reuse
Top functions reviewed by kandi - BETA
Currently covering the most popular Java, JavaScript and Python libraries. See a Sample of DesignPatterns
DesignPatterns Key Features
DesignPatterns Examples and Code Snippets
Community Discussions
Trending Discussions on DesignPatterns
QUESTION
In the Head First Design Patterns book, the authors describe using an iterator to traverse over composite data structures. They provide some sample code which, when executed, prints out a series of menu items stored within the composite. However, if you try to call the iterator more than once, it no longer works as expected and won't produce any results. The following code appears to be causing the problem:
...ANSWER
Answered 2021-Mar-18 at 13:51As the linked issue says in the comments:
QUESTION
I am learning design pattern in python and the subject is singleton objects so, I was writing my main code as PRO003
and import it into PRO004
. This is PRO003
Code:
ANSWER
Answered 2021-Jan-29 at 08:07Class __SingletonObject
is not be instantiated
QUESTION
I just want a quick lookover that I implemented the different fly strategies correctly.
The program simply consists of a duck class that uses an interface for its fly method. The interface has different implementations (namely SimpleFly and NoFly), and a switch statement chooses the correct method based on the specie enum.
As I understand, the strategy pattern is meant to avoid duplicate code between child classes at the same level, which decreases maintainability and extensibility. So instead we abstract out the related algorithms to interfaces and choose them as needed.
CODE:
...ANSWER
Answered 2020-Dec-18 at 20:48I would point out a couple issues of semantics and terminology.
- It's confusing to have a method named
fly
that can be implemented as not flying. Naming the methodtryToFly
or documenting the method as merely an attempt are two ways of addressing this confusion. The software principle to reference here is Liskov Substitution. - The base class does not implement one of the strategies; rather, it composes a strategy. The purpose of the Strategy pattern is to avoid subclassing through composition.
- To reiterate one of the comments,
Duck
should accept an instance ofIFly
directly in its constructor (or a setter method) rather than switching on an enum. Another goal of the Strategy pattern is to avoid branching logic.
The essence of the pattern is that you've avoided creating multiple subclasses of Duck
by instead creating multiple implementations of IFly
. This has the advantage that those IFly
implementations can be reused without a complex inheritance hierarchy, e.g. WILD
and CITY
can share one strategy.
As mentioned in the comments, strategies also have the advantage that a Duck
could change its strategy at runtime. For example, IFly
might be implemented by Soar
and Glide
so that a Duck
would switch between these different strategies depending on the wind.
QUESTION
I am playing with php 7 and phpunit 6. Here is the test I wrote:
...ANSWER
Answered 2017-Feb-14 at 11:16I found the answer:
I was excuting my test with this command line:
QUESTION
I use a LocalContainerEntityManagerFactoryBean
to setting up a JPA EntityManagerFactory
.
Among the scanned entities I scan with setPackagesToScan
I have a User entity that implement spring security interface UserDetails
.
When I lunch my application I have this error:
...ANSWER
Answered 2019-Jun-05 at 13:20I bypassed the problem by removing the implementation of the UserDetails
interface from my User
entity, and set up a new mechanism to recover the GrantedAuthority
necessary for Spring Security.
But I still do not understand why this interface implementation poses a problem with setPackagesToScan
used by the JPA EntityManagerFactory
.
If somone can give us an explanation?
QUESTION
I am trying to make_pair
with a unique_ptr like in the example below
(The code is a C++ implementation of the Facade Design pattern)
...ANSWER
Answered 2018-Jun-30 at 15:08Is this due to the old version of G++ shipped by Apple?
No. It is because you are trying to copy the unique pointer by passing it to make_pair
and insert
.
std::unique_ptr
is not copyable. In fact it is move-only. Change to:
QUESTION
I am trying to test the method:
...ANSWER
Answered 2018-Feb-25 at 19:32I'd follow the XP rule of doing the simplest thing that could possibly work. You don't need to mock anything, so just use the objects directly.
QUESTION
I am trying to make a class ShapeManager
which is instantiated only once, and have a base class Shape
(and all of its children) have access to it. This would result in a structure that looks like this:
ShapeManager
Shape
└Square
└Triangle
└Circle
ANSWER
Answered 2018-Jan-31 at 03:26Don't try and make a global variable accessible through all your code. Make a certain object accessible only to who needs it. Thus, make a private ShapeManager
in Shape and pass it through Shapes
constructor.
But it's still strange that Shape
has to have access to ShapeManager
.
EDIT - Comment by the author: My main motivation to creating a ShapeManager is to store a reference to m_shapes, m_world, and m_gen, but i didn't want every shape object to have those 3 reference variables.
You can have a struct that stores your 3 reference variables and each object that needs access to them would have a private struct.
Some other file:
QUESTION
I am from C++ background, recently started learning Design Patterns.
I am facing problems with this code from Head First Design Patterns:
Link: PizzaStore.java
...ANSWER
Answered 2017-Nov-28 at 15:19PizzaStore class already contains a SimplePizzaFactory object
Well, PizzaStore have a non-initialized attribute of type SimplePizzaFactory. In the PizzaStore constructor, that attribute is initialized with a reference to the constructor argument. This is an usual pattern in Java code.
The passed-on object is not initialized with any data (which needs to be copied by PizzaStore Constructor)
There is no need to add initialization code in the constructor, is asumed that the SimplePizzaFactory is already initialized. That factory is not copied, is referenced by the PizzaStore attribute, so the factory inside the PizzaStore, after the constructor is executed, is an already initialized object.
QUESTION
I want to create Collection of stubs so that first Item when I call getId() method return 0, second Item.getId() return 1 and so on. Value of getId() method must be equal index of element. I try this
...ANSWER
Answered 2017-Jun-05 at 16:06What you need to do is to mock Item
as well.
Community Discussions, Code Snippets contain sources that include Stack Exchange Network
Vulnerabilities
No vulnerabilities reported
Install DesignPatterns
Support
Reuse Trending Solutions
Find, review, and download reusable Libraries, Code Snippets, Cloud APIs from over 650 million Knowledge Items
Find more librariesStay Updated
Subscribe to our newsletter for trending solutions and developer bootcamps
Share this Page