Design Pattern Learning Notes Generator pattern

Generator ModeEncapsulates a product's construction process and allows for construction by step. Separates the construction and presentation of a complex object so that the same construction process can create different representations.

Four types of roles in the builder pattern structure :

Product: The complex object that you want to build.

Abstract Builder: An abstraction builder is an interface that defines methods for returning a product object in addition to defining several methods for each component that creates a Product object.

Concrete Generator (ConcreteBuilder): A class that implements the Buidler interface.

Conductor (director): the conductor is a class that contains the variables that the builder interface declares, and the responsibility of the conductor is to provide the user with a concrete generator that constructs a complex product object using a specific generator.

Advantages of the generator:

1, the creation process of a complex object is encapsulated;

2, allow the object to be created through multiple steps, and can change the process (this is different from the Factory mode with only one step);

3, to the customer hide the performance of the product inside;

4, the implementation of the product can be replaced, because the customer only see an abstract interface.

Disadvantages of the generator pattern:

1, compared with the factory model, using the generator mode to create the object of the customer, need to have more domain knowledge;

use of the generator mode:

1, often used to create a composite structure;

Import Javax.swing.jbutton;import javax.swing.jlabel;import javax.swing.jpanel;import Javax.swing.JTextField;    /** * Products * */public class Panelproduct extends jpanel{JButton button;    JLabel label; JTextField TextField; }

/** * Abstract builder * */public Interface Builder {public void Buildbutton ();     public void Buildlabel ();     public void Buildtextfield (); Public JPanel Getpanel (); }

import javax.swing.jbutton;import javax.swing.jlabel;import javax.swing.jpanel;import  javax.swing.jtextfield; /** *  Specific Generators  * */public class ConcreteBuilder  implements builder{     private panelproduct product;      public concretebuilder ()  {        product  = new panelproduct ();     }     public void  buildbutton ()  {        product.button = new  JButton ("button");     }     public void buildlabel ()  {         product.label = new jlabel ("label");     }     public void buildtextfield ()  {         p Roduct.textfield = new jtextfield ("text box");    }      public jpanel getpanel ()  {        product.add ( Product.button);         product.add (Product.label);         product.add (Product.textfield);         return product;    } }

import javax.swing.jpanel; /** *  conductor  * */public class  Director {     private Builder builder;      public director (Builder builder)  {         This.builder = builder;    }     public jpanel  constructproduct ()  {        builder.buildbutton ();         builder.buildlabel ();         builder.buildtextfield ();        jpanel panel =  Builder.getpanel ();         return panel;    }  }

import javax.swing.jframe;import javax.swing.jpanel; public class client {      public static void main (String[] args)  {         builder builder = new concretebuilder ();         director director = new director (builder);         jpanel panel = director.constructproduct ();         jframe frame = new jframe ();         frame.add (panel);         frame.setbounds (12, 12 ,  200, 120);         frame.setdefaultcloseoperation ( Jframe.dispose_on_close);         frame.setvisible (True);     } }

reference:"Head first design mode"

Http://www.cnblogs.com/binger/archive/2012/08/22/2650798.html http://skhero2012.iteye.com/blog/1489808

Design Pattern Learning Notes Generator pattern