design_pattern | 二十三种设计模式JAVA实现 | Architecture library

 by   SandyJiang Java Version: Current License: No License

kandi X-RAY | design_pattern Summary

kandi X-RAY | design_pattern Summary

design_pattern is a Java library typically used in Architecture applications. design_pattern has no bugs, it has no vulnerabilities, it has build file available and it has low support. You can download it from GitHub.


            kandi-support Support

              design_pattern has a low active ecosystem.
              It has 31 star(s) with 36 fork(s). There are 4 watchers for this library.
              It had no major release in the last 6 months.
              design_pattern has no issues reported. There are no pull requests.
              It has a neutral sentiment in the developer community.
              The latest version of design_pattern is current.

            kandi-Quality Quality

              design_pattern has 0 bugs and 0 code smells.

            kandi-Security Security

              design_pattern has no vulnerabilities reported, and its dependent libraries have no vulnerabilities reported.
              design_pattern code analysis shows 0 unresolved vulnerabilities.
              There are 0 security hotspots that need review.

            kandi-License License

              design_pattern does not have a standard license declared.
              Check the repository for any license declaration and review the terms closely.
              Without a license, all rights are reserved, and you cannot use the library in your applications.

            kandi-Reuse Reuse

              design_pattern releases are not available. You will need to build from source code and install.
              Build file is available. You can build the component from source.
              design_pattern saves you 564 person hours of effort in developing the same functionality from scratch.
              It has 1318 lines of code, 213 functions and 131 files.
              It has low code complexity. Code complexity directly impacts maintainability of the code.

            Top functions reviewed by kandi - BETA

            kandi has reviewed design_pattern and discovered the below as its top functions. This is intended to give you an instant insight into design_pattern implemented functionality, and help decide if they suit your requirements.
            • Main entry point
            • Shortcut for testing
            • The main entry point
            • Test program
            • Main method
            • Entry point for the Terminal
            • The main method
            • Main runner
            • Main method for testing
            • Main method
            • Entry point
            • The main method
            • Handle state transitions
            • Set state
            • Removes an observer from the set
            • Checks if the current aggregator is done
            • Set the B builder part
            • Gets the current item
            • Executes the action
            • Visits the given visitor visit this element
            • Makes the visitor visit this element
            • Retrieves the first item in the aggregate
            • Visit a concrete element B
            • Handles an event
            • Handle a request
            • Returns the next item
            • Displays the current subject
            • Displays the named depth
            • Visit a concrete element
            • Send a message
            • Invoked after decorator is invoked
            Get all kandi verified functions for this library.

            design_pattern Key Features

            No Key Features are available at this moment for design_pattern.

            design_pattern Examples and Code Snippets

            No Code Snippets are available at this moment for design_pattern.

            Community Discussions


            Observer - specifying modifications of interest explicitly - JAVA implementation
            Asked 2020-Dec-10 at 16:55

            I asked here how I should handle the situation when I need to inform observers only when specific attribute of object changes.

            I received very nice reply with reference to GoF where is written:

            Blockquote Specifying modifications of interest explicitly. You can improve update efficiency by extending the subject's registration interface to allow registering observers only for specific events of interest. When such an event occurs, the subject informs only those observers that have registered interest in that event. One way to support this uses the notion of aspects for Subject objects. To register interest in particular events, observers are attached to their subjects using

            void Subject::Attach(Observer*, Aspects interest);

            Blockquote where interest specifies the event of interest. At notification time, the subject supplies the changed aspect to its observers as a parameter to the Update operation. For example:

            void Observer::Update(Subject*, Aspect& interest);

            This makes sense and I would like to ask how to correctly implement this in Java. I have few ideas but I am not sure if there isn't something better.

            Let's imagine I have subject class WeatherStation[temperature, humidity, windSpeed ...] and I have observer class LimitedDisplay[show (shows only temperature and humidity) and for some reason I need that the display should be able to differentiate when only temperature was changed and when only humidity was changed.

            I was thinking that I could create some enum WeatherStationInterest[TEMPERATURE, HUMIDITY WIND_SPEED...] and then have the subject interface like this:



            Answered 2020-Dec-10 at 11:31

            Another option is to have a set of interfaces:



            Builder Pattern and LSP
            Asked 2020-Sep-10 at 00:01

            I was going through Builder pattern and had a couple of question that I thought needed clarification

            1. Is builder pattern implemented through Abstract class or through interfaces. There are few posts that uses interface
              ...can list more
              and others uses abstract class

            Note: The way I think is that it should be implemented using Abstract class. This rationale is based on the assumption that this way I may/may not implement them in derived class (as there could be a possibility that a few concrete class does not implement them)...
            This assumption could be entirely wrong though.

            1. If the above assumption is wrong then wont it violate LSP. Since one condition in LSP say that you cant have "not implemented methods" in your derived class.

            Or I have misunderstood it completely...



            Answered 2020-Sep-10 at 00:01

            This became too long for a comment...

            The patterns from the GoF book are older than Java. It was Java that later introduced the (silly) distinction between interface and abstract class. When the GoF refers to an interface, they simply mean an abstraction, and you can implement it using any language feature that enables abstraction.

            That being said, the GoF Builder Pattern is overcomplicated. The pattern is useful even without polymorphism. And I think that is how it's most often implemented. If you're using Java, that would be Josh Bloch's Builder Pattern from Effective Java.

            I don't mean to dismiss the LSP question, but if the real goal here is to learn to use a Builder effectively, then my advice is to ignore the (outdated) version from the GoF and look at a modern implementation where that question doesn't arise. If you really wanted to ask about the LSP, then I suggest a new question focused specifically on that topic, separate from the Builder Pattern.

            To more directly address the questions in the OP,

            1. The builder pattern can be implemented through abstract classes or through interfaces. It does not matter which. Modern implementations more often use neither.
            2. LSP conformity will depend on how you implement (and document) the pattern. It would be possible to violate the LSP (or not) using interfaces or abstract classes. Eliminating both eliminates this question.



            Factory design pattern and violation of OCP (Open-Closed Principle)
            Asked 2020-Apr-12 at 08:13

            The factory in this tutorial obviously violates the OCP. Every time a shape is added to the system, we need to add it in the factory to support it. I'm thinking of another implementation and I'd like to know if there are any drawbacks.



            Answered 2020-Apr-12 at 08:13

            There are a few drawbacks to this method.

            Firstly, when the Class passed to getShape requires a constructor argument, the .newInstance will fail. For example:



            How does the Flyweight pattern in Java work with respect to memory management?
            Asked 2020-Mar-24 at 21:47

            I feel like I have an ok grasp on the design pattern, however I can't seem to get my head around one thing and it doesn't seem to be exactly explained in the resources I've looked at.
            That question is, how is the data common, without the data being static, considering the objects are separate entities?


            In this example, I cannot figure out where the optimisation is occurring, as it looks as if the objects are just being created each time as normal.



            Answered 2017-Nov-13 at 12:36

            The ShapeFactory in your linked example will create one Circle per color:



            In PHP, how to pass a class instance to another class's constructor
            Asked 2019-Dec-12 at 21:09

            I am trying to make an implementation of the Bridge Design Pattern, following the steps on Tutorials Point. I am converting the code from Java to PHP and changing some names.

            The problem is, when I try to pass the concrete bridge implementer class to the concrete class implementing interface, an error is throw.

            My code is as follows:



            Answered 2018-Jun-20 at 02:49

            yeah should be $redRocket->launch(); instead of $redRocket.launch(); like what nigel ren said



            Copy constructor on "Observer pattern"
            Asked 2019-Oct-03 at 16:29

            Suppose we a design pattern similar to this one:



            Answered 2019-Oct-03 at 16:29

            A move constructor would be appropriate:



            Singleton test not working when var is instantiated with *
            Asked 2019-Jun-12 at 22:01

            I'm following the Singleton design pattern as described in this book ( and I have this code in file "singleton2.go":



            Answered 2019-Jun-12 at 22:01

            Follow the logic of your code and it's apparent where the problem is.

            When you declare, but do not initialize the singleton (var instance *singleton) then instance is nil. Calling GetInstance evaluates instance == nil as true and returns a new *singleton every time it is called. That is why counter2 will never equal expectedCounter - each call to GetInstance is returning a new counter instance.

            When you initialize the singleton instance (var instance = &singleton{}) then calls to GetInstance will return that singleton instance since it is not nil.

            I imagine you'd want to modify GetInstance to something like this:



            How to access a parent class attribute without breaking data encapsulation?
            Asked 2019-Jun-09 at 07:39

            In the 1994 book Design Patterns: Elements of Reusable Object-Oriented Software by the "Gang of Four", I noticed in the C++ code examples that all methods are either declared as public or protected (never as private) and that all attributes are declared as private (never as public or protected).

            In the first case, I suppose that the authors used protected methods instead of private methods to allow implementation inheritance (subclasses can delegate to them).

            In the second case, while I understand that avoiding public and protected attributes prevents breaking data encapsulation, how do you do without them if a subclass need access a parent class attribute?

            For example, the following Python code would have raised an AttributeError at the get_salary() method call if the _age attribute was private instead of protected, that is to say if it was named __age:



            Answered 2019-Jun-09 at 07:39

            I have finally found out an obvious solution by myself: redeclaring the private attribute of the parent class in the subclass:



            How to protect function from base class in Python?
            Asked 2019-Apr-15 at 20:18

            I am currently learning the Template Method pattern in python.

            I am wondering if there is any way to protect some of the functions from the base class so that the subclass cannot overwrite? As below, the _primitive_operation_3 from the subclass overwrites the same function from the base class.



            Answered 2019-Apr-15 at 18:38

            You can't prevent subclasses from using the same names, no. You can protect names against accidental shadowing, however, by giving the name a double underscore prefix:



            How to keep or properly cast object Type?
            Asked 2019-Jan-12 at 21:30

            Im dealing with this problem.

            I have base class Worker that is abstract. Its base class for Driver and AmountBonus. That Bonus is writed based on Decorator design pattern. My decorator decorate one of property from Worker.

            How it looks in code:



            Answered 2019-Jan-10 at 19:09

            What you're doing makes no sense. Decorators are utility classes; they overlay programmatic functionality on to the classes they decorate. They are not something that can nor should be persisted to something like a database.

            In other words, if your object is a Driver, then you need to keep it a Driver, not wrap it in an AmountBonus decorator and then attempt to persist that. Later, if you need whatever functionality the AmountBonus decorator adds again, you simply wrap your Driver instance in it again.

            It doesn't even look like you're doing anything interesting with the decorator here, but if there is something that occurs just by the act of wrapping a Driver instance, then you'll need to fetch out somehow that wrapped Driver instance afterwards to actually save that and not your decorator.


            Community Discussions, Code Snippets contain sources that include Stack Exchange Network


            No vulnerabilities reported

            Install design_pattern

            You can download it from GitHub.
            You can use design_pattern like any standard Java library. Please include the the jar files in your classpath. You can also use any IDE and you can run and debug the design_pattern component as you would do with any other Java program. Best practice is to use a build tool that supports dependency management such as Maven or Gradle. For Maven installation, please refer For Gradle installation, please refer .


            For any new features, suggestions and bugs create an issue on GitHub. If you have any questions check and ask questions on community page Stack Overflow .
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