重构－保护

重构前的代码，使用字符串处理状态

package org.zsk.refact;

public class SystemPermission {
private String state;
private boolean granted;

public final static String REQUESTED = "REQUESTED";
public final static String CLAIMED = "CLAIMED";
public final static String DENIED = "DENIED";
public final static String GRANTED = "GRANTED";

public SystemPermission() {
// TODO Auto-generated constructor stub
state = REQUESTED;
granted = false;
}

public void claimed(){
if (state.equals(REQUESTED)){
state = CLAIMED;
}
}

public void denied(){
if (state.equals(CLAIMED))
state = DENIED;
}

public void granted(){
if (state.equals(CLAIMED)){
state = GRANTED;
granted = true;
}
}

public boolean isGranted(){
return granted;
}

public String getState(){
return state;
}

/** *//**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
SystemPermission permission = new SystemPermission();
System.out.println(permission.getState());


}

}

重构后的代码，使用类来保护状态不会被吴改。

package org.zsk.refact;

public class SystemPermissionRf1 {
private boolean granted;
private PermissionState permission;

// public final static String REQUESTED = "REQUESTED";
// public final static String CLAIMED = "CLAIMED";
// public final static String DENIED = "DENIED";
// public final static String GRANTED = "GRANTED";

public SystemPermissionRf1() {
setState(PermissionState.REQUESTED);
granted = false;
}

public void claimed(){
if (getState().equals(permission.REQUESTED)){
setState(permission.CLAIMED);
}
}

public void denied(){
if (getState().equals(permission.CLAIMED)){
setState(permission.DENIED);
}
}

public void granted(){
if (getState().equals(permission.CLAIMED)){
setState(permission.GRANTED);
granted = true;
}
}

public boolean isGranted(){
return granted;
}

private void setState(PermissionState permission){
this.permission = permission;
}

public String getState(){
return permission.toString();
}


/** *//**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
SystemPermissionRf1 permission1 = new SystemPermissionRf1();
System.out.println(permission1.getState());


}


}

package org.zsk.refact;


public final class PermissionState{
private final String name;

PermissionState(String name){
this.name = name;
}

public String toString(){
return name;
}

public final static PermissionState REQUESTED = new PermissionState("REQUESTED");
public final static PermissionState CLAIMED = new PermissionState("CLAIMED");
public final static PermissionState DENIED = new PermissionState("DENIED");
public final static PermissionState GRANTED = new PermissionState("GRANTED");
}