The adapter mode for Java design mode

Defined:

The adapter pattern transforms the interface of a class into another interface that the customer expects. Those classes that would otherwise not work together because of incompatible interfaces can work together.

Categories of adapters:

1. 1. Combination: Adapter in a combined way becomes an object adapter feature: Combine the "ligand" as an object into the adapter class to modify the target interface wrapper by the appropriate person

2. Inheritance: The use of inheritance is called Class adapter features: Through multiple inheritance incompatible interface, to achieve the matching of the target interface, a single class to achieve a suitable

Role:

1. Transparent: Through the adapter, the client can invoke the same interface, and thus is transparent to the client. This is simpler, more straightforward, and more compact.

2. Reuse: Reusing existing classes solves the problem of inconsistent requirements for existing and reused environments.

3. Low coupling: Decoupling the target class from the adapter class and reusing existing adapters by introducing an adapter without modifying the original code (following the open and closed principle)

Example project: A laptop requires a three-phase socket charge, but there is a two-phase power supply, you need to create an adapter to do two three-phase charging

code example

1. Create a three-phase receptacle interface

1 /** 2 * Three-phase socket interface 3  */4publicinterface  threeplugif {5     / / use three-phase current to charge 6public     void  powerwiththree (); 7 8 }

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2. Create a two-phase power supply class

1  Public class Gbtowplug {2     // power supply with two-phase current 3      Public void Powerwithtow () {4         SYSTEM.OUT.PRINTLN ("power supply using two-phase current"); 5     }6 }

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3. Create a notebook class that uses three-phase sockets for charging, but the power supply is two-phase and requires an adapter for conversion

1  Public classNoteBook {2     Privatethreeplugif plug;3      PublicNoteBook (threeplugif plug) {4          This. Plug =plug; 5     }6     //charging with a socket7      Public voidcharge () {8 Plug.powerwiththree ();9         Ten     } One      A}

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4-1. Create an adapter (combo)

1 /**2 * Two phase to three-phase socket adapter3  * */4  Public classTowplugadapterImplementsThreeplugif {5     PrivateGbtowplug plug;6      Publictowplugadapter (gbtowplug plug) {7          This. Plug =plug;8     } 9 @OverrideTen      Public voidPowerwiththree () { OneSystem.out.println ("Through conversion"); A Plug.powerwithtow (); -     } -  the}

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4-2. Create an adapter (inherit)

1 /**2 * Adopt the Inheritance method to realize3  * */4  Public classTowplugadapterextends5     extendsGbtowplugImplementsThreeplugif {6 7 @Override8      Public voidPowerwiththree () {9System.out.println ("Inheritance mode implementation");Ten          This. Powerwithtow (); One     } A}

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5. Test class

1  Public classTest {2      Public Static voidMain (string[] args) {3         /**Combination Mode*/4Gbtowplug tow =NewGbtowplug ();5Threeplugif three =NewTowplugadapter (tow);6NoteBook NB =NewNoteBook (three);7 Nb.charge ();8         /**How to inherit*/9three =Newtowplugadapterextends ();TenNB =NewNoteBook (three); One Nb.charge (); A     } -}

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The adapter mode for Java design mode