java常用设计模式之适配器模式
------------------------------ 适配器模式(adapter) -------------------------------
(1)
适配器模式的意图是将一个已存在的类/接口进行复用,将其转换/具体化成客户希望的另外的一个类/接口。
(2)
如何实例复用：
将要进行复用的类，放到目标类的构造方法中，进行实例化，然后在目标类的相应方法中，进行调用，修改原来方法中的参数，或添加相应的逻辑。即复用了已有类的原来方法。要被复用的类：
public class Adaptee{
??? public long getPower(long base,long exp){
?????? long result=1;
?????? for(int i=0;i<exp;i++)
?????????? result*=base;
?????? return result;
??? }
}目标类：--也可直接实现，不用接口。
public interface Target{
??? public long get2Power(long exp);
}public class Adapter implements Target{
??? private Adaptee pt;
??? public Adapter(){
?????? pt = new Adaptee();
??? }
??? public long get2Power(long exp){
?????? return pt.getPower(2,exp);?? ---修改原来方法中的参数，
??? }
}(3)
又如：
在SCM中添加的方法:
已有接口:
public boolean updateRecordStates(Double recordId,Double tableNameMapping,int state,boolean subRecordUpdate) throws RemoteException;
已有实现类:
public boolean updateRecordStates(Double recordId,Double tableNameMapping,int state,boolean subRecordUpdate) throws RemoteException
{
return moveTable.updateRecordStates(recordId,tableNameMapping,state,subRecordUpdate);
}若采用适配器模式:
接口:
public boolean updateStatesAdapterForSelfPanel(Double recordId,Double tableNameMapping,int state) throws RemoteException;
实现类:
public boolean updateStatesAdapterForSelfPanel(Double recordId,Double tableNameMapping,int state) throws RemoteException
{
?return this.updateRecordStates(recordId,tableNameMapping,state,false);
}
