java design patterns pdf

complex, there are many properties, and these properties are references to other objects, which may include a lot of object references. By encapsulating these complexities, you can use the build mode.Recommended Link: http://www.cnblogs.com/cbf4life/archive/2010/01/14/1647710.html4. Façade modeThis pattern feels like a replica of the service layer. For example DAO we define a lot of persistence methods, we use the service layer to make the DAO atomic method into business logic, and then provide

my Code slice public class man { private string head; private string body; private string foot; public String gethead () { return head; } public void Sethead ( String head) { this.head = head; } public String getbody () { return body; } public void Setbody ( String body) { this.body = body; } public String getfoot () { return foot; } public void Setfoot (String foot) { This.foot = foot; }}[Java] View plaincopyprint? To see code s

layer. Object-oriented methods can be used to store, update, delete records of a database, and query database information. Persistent layer can also choose Ibatis, etc. Data layer: Used to store business data for the upper call, mainly refers to some database systems. The 3 framework features of the classic SSH (Struts, Spring, Hibernate) are different, and depending on the functional hierarchy of the Web application, these 3 frameworks can be applied to various levels, ultimately enabling the

implementation. Because the structure inside the parameters are eat interface, as long as the implementation of the Eat class can be passed in, that is to show　　　　　　　　　　Likeeat likeeat = new Endeat (New Eatfoot (New Inrestaurant (New Gotorestaurant (New Findinmap (person)))))The look of this structure. So when calling Likeeat.eat () , and because of each specific decorator class, first call super.eat (); method, and the Super has been passed by the construction and pointed to a specific decorat

the randomness of the thread, Maybe T1 just went in to execute if control statement, this time, was T2 grabbed the CPU execution, this time, T2 began to execute, found that this time t is still null, so T2 also go in to execute if the statement of control, then there will be more than one object is created, so lazy type has a thread safety problem.Therefore, in the development we generally choose the A hungry man-type singleton mode without the thread safety problem.What kind of singleton mode

JavaWhat are the common design patterns? Describes the Factory mode. Total at species, divided into three categories: creation, structural, behavioralI only remember the usual ones. 6 , 7 species, respectively:Created (Factory, factory method, abstract factory, Singleton)Structural type (packaging, adaptors, combinations, proxies)Behavior (Viewer, template, strategy)then talk about your understanding of th

) {Mediator Med = new Concretemediator ();The boss is here.Med.notice ("Boss");The client is here.Med.notice ("Client");}}ResultOrdinary employees work hardFront desk attention!Applicability:1. A group of objects communicates in a well-defined but complex way.The resulting interdependence structure is confusing and difficult to understand.2. An object that references very many other objects and communicates directly with those objects makes it difficult to duplicate the object.3. Want to customi

corresponding get function. When we call them, we only need to call the Public matching code of the above parent class to obtain the correct data. The following is the code snippet after the facade mode is introduced to the above table structure: ......String name, ID, age;Studentselect student = New Studentselect ();Student.exe cute ();Name = Student. getname ();ID = Student. GETID ();Age = Student. getage ()...... The above mechanism can also be used for SQL statements updated in the

whole pattern of using lambda expressions is greatly simplified because we can completely abolish these classes. Let's see if the macro Class (client) uses a lambda expression instead of the command class's effect.Filereceiver.closefile (), new--- Macro.run (); If you can realize that each lambda expression is executing a separate method call, you can further refine it. Therefore, you can use the method reference directly.New Macro (); Macro.record (filereceiver::openfile); Macro.record (filere

the book to implement the two patterns is completely different (I think this implementation is somewhat arbitrary). the state mode, in particular, uses a separate implementation hierarchy, but I don't think it's necessary unless you assume that the implementation code is not controlled by you (which is, of course, a possibility, but if the code is controlled by you, It is also more concise and practical with a single base class). In addition, the pro

= 0; I ) {sb.append ("-"); } System.out.println (NewString (SB) + This. GetName ()); }} PackageCom.roc.composite;/*** Combined mode *@authorLIAOWP **/ Public classClient { Public Static voidMain (string[] args) {Component root=NewConcretecompany ("root"); Root.add (NewLeaf ("File A")); Root.add (NewLeaf ("File B")); Component file=NewConcretecompany ("File1"); File.add (NewLeaf ("File C")); File.add (NewLeaf ("File D")); Root.add (file); Root.display (1); }}Combination mode for Scenario

changes of the person being observed4. The actual observer classConcretobserver inherits Observer interface, implements update ()Observer instance:Publicinterfacestudentsubject{publicvoidaddobserver (ParentObserverone); Publicvoidmoveobserver (Parentobserverone);p ublicvoidnotifyobserver ();} packagesuperhakcetoolspackage;importjava.util.arraylist;publicclassstudent Implementsstudentsubject{privatefloatgrades;privatearraylistThis article is from the "Superhakce" blog, make sure to keep this sou

Design Patterns ----------- Singleton design patterns, Singleton Design PatternsHungry Chinese Style: class Single {// do it in advance! Private static final Single s = new Single (); // private constructor cannot use new to create an object! Private Single () {}// public st

); } //Protect the default construction child protected Singleton3 () {} //Static factory method to return such unique instances public static Singleton3 getinstance (String name) { if (name = = null) { Name = Singleton3.Class.getname (); System.out.println ("name = = NULL" +"--->name=" +name); } if (map.get (name) = = null) { try { Map.put (name, (Singleton3) class.forname (name). newinstance ()); } catch (Instantiationexception e) { E.printstacktr

I saw this article in the Java Forum. The author compared the 32 Java models in a simple language, which has a good inspiration, but unfortunately I didn't give a specific meaning, I added it to the back. These are the simplest introductions. If you want to learn them, I suggest you take a look at Dr. Yan Hong's book "Java and

Newwidgets (); - } - } - } - Public classFactoryconstraint { in Public Static voidMain (string[] args) { - NewFoo2Newintegerfactory ()); to NewFoo2Newwidget.factory ()); + } -}View CodeClassTemplate method:Another way is to use the template method design pattern, by implementing abstract class (template) abstract method to create objects, also can get compile time type check, the following is the code:1 PackageC

Create pattern 1. Singleton mode (Singleton pattern) 2. Factory method Pattern (Factory mode) 3. Abstract Factory mode (Factory pattern) 4. Builder Pattern 5. Prototype mode (Prototype pattern) Structural mode 6. Adapter mode (Adapter pattern) 7. Bridging mode (bridge pattern) 8. Decorator mode (Decorator pattern) 9. Combination mode (Composite pattern) 10. Appearance mode (facade pattern) 11. Enjoy meta mode (Flyweight pattern) 12, Agent mode (proxy pattern) Behavioral

JAVA design patterns ---------- Proxy) Here is a brief introduction to the use of the most basic proxy. Agency: Simply put, one person or one institution takes action on behalf of another person or another institution. In some cases, a customer does not want or cannot directly reference an object, but the proxy object can play a mediation role before the client a

The disadvantage of creating an object with the New keyword is that the coupling is too high, and the factory design pattern uses the Java reflection mechanism to instantiate the object to reduce the degree of couplingPackageCn.buaa;Importjava.util.Date;Interfacefruit{ Public voideat ();}classAppleImplementsfruit{@Override Public voideat () {System.out.println ("Eat apples"); }}classOrangeImplementsfruit{@O

PackageShipeiqidemo;/** A common design pattern in Java: Adapter * Source: A subclass to implement the interface, then you have to implement the interface of all the abstract methods, sometimes the abstract method * a lot, but do not need to implement all, so at this time define an abstract class to implement this interface, and then through the subclass to inherit * In this abstract class, this abstract cl