Question: “If any error occurs when running the getInstance() method … and I still want the getInstance() method return the right result. How to achieve this?” Short answer: you can’t guarantee it. There are a large number of conditions which can throw a Throwable There are 2 main types (subclasses) of Throwable : Exception and … Read more
This is one simple example for your singleton. Feel free to add setters and getters as you need it for the fields. I’m not sure what the set-method in your diagram should do but maybe you don’t need it anyway. public class LibraryInfo { private static final LibraryInfo instance = new LibraryInfo(); public static LibraryInfo … Read more
This is the non-lazy method of implementing the Singleton pattern for languages that support it. It’s perfectly acceptable to do this, especially since it’s one of the ways of implementing a thread-safe Singleton. However, if your Singleton object is expensive (see lazy initialization) to create, then it might not be appropriate to create it in … Read more
Since you need to adapt to different mechanics\protocols, you can implement Adapter pattern. Also, adapter can be chosen at runtime, you can also implement Factory pattern to instantiate an adapter. And then Strategy pattern to have adapters and factories. All this being done with IoC to inject dependencies like adapters or factories solved Abstract Factory … Read more
list is one of the many classes provided by the Standard Library. It behaves like any other class type: int : integer int* : pointer to integer Observer : Observer instance Observer* : pointer to Observer instance list<Observer> : list of Observers list<Observer*>* : pointer to list of pointers to Observers solved Difference between list* … Read more
As far as I know, the book AntiPatterns by Brown et al, 1998 may have been the first to popularise the term. It defines an anti-pattern like this: “An AntiPattern is a literary form that describes a commonly occurring solution to a problem that generates decidedly negative consequences.” I think that it’s worthwhile to pay … Read more
Well, the obvious choces are Strategy (one logger that can be configured to use different output options) and Composite (multiplex output over several output outions). So something like this (in Java): public class Logger { public interface LogOutput { void out(final String s); } // Composite – use to send logging to several destinations public … Read more
Patterns of Enterprise Application Architecture by Martin Fowler solved Book for software design [closed]
There are quite a few ways that you can collaborate over a distance, though none that I know of that are django specific. I assume that by designer you mean that your friend will be working on the HTML and CSS aspects of the project. Since you are already using Git, you could setup a … Read more
Simply change your first for loop to decrement instead of increment for (int i = lines; i > 0; i–) { instead of for (int i = 1; i <= lines; i++){ 1 solved creating number patterns in java(continued) [closed]