建造者模式可以將一個(gè)產(chǎn)品的內(nèi)部表象與產(chǎn)品的生成過(guò)程分割開(kāi)來(lái)，從而可以使一個(gè)建造過(guò)程生成具有不同的內(nèi)部表象的產(chǎn)品對(duì)象。

UML圖示：


1. com.cleversoft.designpatterns.builder2.PostalClert.java:
package?com.cleversoft.designpatterns.builder2;

public?class?PostalClert?{
????public?void?construct(LetterBuilder?letterBuilder)?{
????????letterBuilder.buildEnvelop();
????????letterBuilder.buildStamp();
????}
}

2. com.cleversoft.designpatterns.builder2.LetterBuilder.java:
package?com.cleversoft.designpatterns.builder2;

public?abstract?class?LetterBuilder?{
????public?abstract?void?buildEnvelop();

????public?abstract?void?buildStamp();

????public?abstract?Letter?getLetter();
}

3. com.cleversoft.designpatterns.builder2.OrdinaryMailBuilder.java:
package?com.cleversoft.designpatterns.builder2;

public?class?OrdinaryMailBuilder?extends?LetterBuilder?{
????private?Letter?ordinaryMail?=?new?OrdinaryMail();

????public?void?buildEnvelop()?{
????????ordinaryMail.add("ordinaryEnvelop",?0.1);
????}

????public?void?buildStamp()?{
????????ordinaryMail.add("ordinaryStamp",?1.0);
????}

????public?Letter?getLetter()?{
????????return?ordinaryMail;
????}

}

4. com.cleversoft.designpatterns.builder2.RegisteredLetterBuilder.java:
package?com.cleversoft.designpatterns.builder2;

public?class?RegisteredLetterBuilder?extends?LetterBuilder?{
????private?Letter?registeredLetter?=?new?RegisteredLetter();

????public?void?buildEnvelop()?{
????????registeredLetter.add("registeredEnvelop",?2.0);
????}

????public?void?buildStamp()?{
????????registeredLetter.add("registeredStamp",?15.0);
????}

????public?Letter?getLetter()?{
????????return?registeredLetter;
????}
}

5. com.cleversoft.designpatterns.builder2.Letter.java:
package?com.cleversoft.designpatterns.builder2;

public?interface?Letter?{

????public?abstract?void?add(String?type,?double?price);

????public?abstract?void?list();

}

6. com.cleversoft.designpatterns.builder2.OrdinaryMail.java:
package?com.cleversoft.designpatterns.builder2;

import?java.util.Enumeration;
import?java.util.Hashtable;

public?class?OrdinaryMail?implements?Letter?{
????Hashtable<String,?Double>?letter?=?new?Hashtable<String,?Double>();

????/*
?????*?(non-Javadoc)
?????*?
?????*?@see?com.cleversoft.designpatterns.builder2.ILetter#add(java.lang.String,
?????*??????double)
?????*/
????public?void?add(String?type,?double?price)?{
????????letter.put(type,?price);
????}

????/*
?????*?(non-Javadoc)
?????*?
?????*?@see?com.cleversoft.designpatterns.builder2.ILetter#show()
?????*/
????public?void?list()?{
????????System.out.println("Ordinary?Letter?List\n");
????????Enumeration?keys?=?letter.keys();
????????while?(keys.hasMoreElements())?{
????????????String?key?=?keys.nextElement().toString();
????????????String?value?=?letter.get(key).toString();
????????????System.out.println(key?+?"?"?+?value?+?"元");
????????}

????}
}

7. com.cleversoft.designpatterns.builder2.RegisteredLetter.java:
package?com.cleversoft.designpatterns.builder2;

import?java.util.Enumeration;
import?java.util.Hashtable;

public?class?RegisteredLetter?implements?Letter?{
????Hashtable<String,?Double>?letter?=?new?Hashtable<String,?Double>();

????/*
?????*?(non-Javadoc)
?????*?
?????*?@see?com.cleversoft.designpatterns.builder2.ILetter#add(java.lang.String,
?????*??????double)
?????*/
????public?void?add(String?type,?double?price)?{
????????letter.put(type,?price);
????}

????/*
?????*?(non-Javadoc)
?????*?
?????*?@see?com.cleversoft.designpatterns.builder2.ILetter#show()
?????*/
????public?void?list()?{
????????System.out.println("Registered?Letter?List\n");
????????Enumeration?keys?=?letter.keys();
????????while?(keys.hasMoreElements())?{
????????????String?key?=?keys.nextElement().toString();
????????????String?value?=?letter.get(key).toString();
????????????System.out.println(key?+?"?"?+?value?+?"元");
????????}

????}
}

8. com.cleversoft.designpatterns.builder2.Main.java:
package?com.cleversoft.designpatterns.builder2;

public?class?Main?{

????public?static?void?main(String[]?args)?{
????????LetterBuilder?lb?=?new?OrdinaryMailBuilder();
????????PostalClert?pc?=?new?PostalClert();
????????pc.construct(lb);

????????Letter?l?=?lb.getLetter();
????????l.list();
????}
}


參考資料：
1. http://terrylee.cnblogs.com/archive/2005/12/19/299878.html
2. 《Java與模式》

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