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();)
