Design pattern (iii) builder mode

Core Essence:

Separate construction of the object subassembly, which is the responsibility of the builder, is separated and assembled (by the director). So that complex objects can be constructed.

Usability:

When the build process of an object is complex

Characteristics:

Because of the realization of the decoupling of the construction and assembly. Different builders, the same assembly, can also make different objects, the same builder, different assembly order can also make different objects. That is to realize the construction algorithm, the decoupling of the Assembly algorithm, to achieve a better reuse

Application Scenarios:

Implementing the example code:

 PackageCom.lp.builder; Public classAirShip {PrivateOrbitalmodule Orbitalmodule;//Orbital Module    PrivateEngine engine;//engine    PrivateEscapetower Escapetower;//Escape pod     Publicorbitalmodule Getorbitalmodule () {returnOrbitalmodule; }     Public voidsetorbitalmodule (Orbitalmodule orbitalmodule) { This. Orbitalmodule =Orbitalmodule; }     PublicEngine Getengine () {returnengine; }     Public voidSetengine (Engine engine) { This. engine =engine; }     Publicescapetower Getescapetower () {returnEscapetower; }     Public voidsetescapetower (Escapetower escapetower) { This. Escapetower =Escapetower; }        }classorbitalmodule{PrivateString name; Orbitalmodule (String name) { This. Name =name; }     PublicString GetName () {returnname; }     Public voidsetName (String name) { This. Name =name; }    }classengine{PrivateString name; Engine (String name) { This. Name =name; }     PublicString GetName () {returnname; }     Public voidsetName (String name) { This. Name =name; }}classescapetower{PrivateString name; Escapetower (String name) { This. Name =name; }     PublicString GetName () {returnname; }     Public voidsetName (String name) { This. Name =name; }}

spacecraft and the build that can be assembled

 Package Com.lp.builder;  Public Interface Airshipbuilder {    Engine builderengine ();    Orbitalmodule builderorbitamodule ();    Escapetower builderescapertower ();}

Spaceship Construction Interface

 Package Com.lp.builder; // assemble the ship .  Public Interface airshipdirector {        AirShip directairship ();}

spacecraft Assembly Interface

 PackageCom.lp.builder; Public classLpairshipbuilderImplementsairshipbuilder{@Override PublicEngine Builderengine () {System.out.println ("Building Li Peng Brand engine"); return NewEngine ("Li Peng Brand Engines"); } @Override Publicorbitalmodule Builderorbitamodule () {System.out.println ("Building Li Peng's orbital module"); return NewOrbitalmodule ("Li Peng Rail module"); } @Override Publicescapetower Builderescapertower () {System.out.println ("Building Li Peng's escape cabin"); return NewEscapetower ("Li Peng Escape Cabin"); }    //Stringbuildr}

Li Peng's Spaceship construction interface

 PackageCom.lp.builder; Public classLpairshipdirectorImplementsAirshipdirector {PrivateAirshipbuilder Builder; Lpairshipdirector (Airshipbuilder builder) { This. Builder =Builder; } @Override PublicAirShip directairship () {Engine e=Builder.builderengine (); Orbitalmodule o=Builder.builderorbitamodule (); Escapetower es=Builder.builderescapertower (); AirShip Ship=NewAirShip ();        Ship.setengine (e);        Ship.setescapetower (es);        Ship.setorbitalmodule (o); returnShip ; }}

Li Peng's spacecraft assembly interface

Design pattern (iii) builder mode