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Java的建造设计模式

2019-11-18 14:32:35
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  分为指导者,抽象建造者,具体建造者
有一个例子

import java.util.*;
import junit.framework.*;

//不同的媒体形式:

class Media extends ArrayList {}
class Book extends Media {}
class Magazine extends Media {}
class WebSite extends Media {}

// 不同媒体的组成元素:

class MediaItem {
 PRivate String s;
 public MediaItem(String s) { this.s = s; }
 public String toString() { return s; }
}

class Chapter extends MediaItem {
 public Chapter(String s) { super(s); }
}

class Article extends MediaItem {
 public Article(String s) { super(s); }
}

class WebItem extends MediaItem {
 public WebItem(String s) { super(s); }
}

// 抽象建造者角色,它规范了所有媒体建造的步骤:

class MediaBuilder {
 public void buildBase() {}
 public void addMediaItem(MediaItem item) {}
 public Media getFinishedMedia() { return null; }
}

//具体建造者角色

class BookBuilder extends MediaBuilder {
 private Book b;
 public void buildBase() {
  System.out.println("Building book framework");
  b = new Book();
 }

 public void addMediaItem(MediaItem chapter) {
  System.out.println("Adding chapter " + chapter);
  b.add(chapter);
 }
 public Media getFinishedMedia() { return b; }
}

class MagazineBuilder extends MediaBuilder {
 private Magazine m;
 public void buildBase() {
  System.out.println("Building magazine framework");
  m = new Magazine();
 }

 public void addMediaItem(MediaItem article) {
  System.out.println("Adding article " + article);
  m.add(article);
 }
 public Media getFinishedMedia() { return m; }
}

class WebSiteBuilder extends MediaBuilder {
 private WebSite w;
 public void buildBase() {
  System.out.println("Building web site framework");
  w = new WebSite();
 }

 public void addMediaItem(MediaItem webItem) {
  System.out.println("Adding web item " + webItem);
  w.add(webItem);
 }

 public Media getFinishedMedia() { return w; }
}

//指导者角色,也叫上下文
class MediaDirector {
 private MediaBuilder mb;
 public MediaDirector(MediaBuilder mb) {
  this.mb = mb; //具有策略模式相似特征的
 }

 public Media prodUCeMedia(List input) {
  mb.buildBase();
  for(Iterator it = input.iterator(); it.hasNext();)

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