战略设计模式

Question

我有一个支持URLConnection的AuthenticationHandler接口,但现在我正在使用Apache HTTP Client.我想为两种连接类型(URLConnection和HTTP Client)提供一个通用的身份验证接口,但它们都有不同的参数和功能.

我该如何设计呢？战略模式是否可行？

import java.net.URLConnection;
import java.util.List;

public interface AuthenticationHandler {

/**
 * this needs to be called by everyone that needs direct access to a link which may have
 * security access rules.
 */
void trustAll();

/**
 *
 * @param URLconnection where you set access state parameters or anything access related
 * @param slice where you could get access config
 * @param initializeSlice is true if you want the proxy to hibernate initialize all hibernated objects
 * @return
 * @throws ConnectionException
 */
void authenticate(URLConnection conn) throws ConnectionException;

List<String> getSingleCookie();

void setSingleCookie(List<String> singleCookies);

CookieManager getCookieManager();

void setCookieManager(CookieManager cookieManager);

boolean isKeepGeneratedCookie();

void setKeepGeneratedCookie(boolean keepGeneratedCookie);

}

我主要担心的是

void authenticate(URLConnection conn) throws ConnectionException;

它最初采用URLConnection conn但现在我们也想添加对HTTP客户端的支持.

Answer 1

对于策略模式,您应该使用以下内容:

public class AuthenticationHandlerImpl implements AuthenticationHandler {

    private Authenticator authenticator;

    void authenticate() throws ConnectionException {
        authenticator.authenticate();
    };

    public void setAuthenticator(final Authenticator  authenticator){
        this.authenticator = authenticator;
    }

}

interface Authenticator {
    void authenticate();
    void setLogin(String login);
    void setPassword(String password);
}

class URLAuthenticator implements Authenticator {
    public void authenticate() {
        //use URLConnection
    };
}

class HTTPClientAuthenticator implements Authenticator {
    public void authenticate() {
        //use HTTPClient
    };
}

用法示例:

AuthenticationHandler handler = new AuthenticationHandlerImpl();
Authenticator authenticator = new HTTPClientAuthenticator();
//or
//Authenticator authenticator = new URLAuthenticator();
authenticator.setLogin(...);
authenticator.setPassword(...);
handler.setAuthenticator(authenticator)

handler.authenticate();

对于创建,Authenticator您可以使用模式FactoryMathod:

class AuthenticatorFactory {

    private AuthenticatorFactory(){}

    //type of param may be enum or other
    public static Authenticator createAuthenticator(... param) {
        if (param == ...) {
            return new URLAuthenticator();
        } else if (param == ...) {
            return new HTTPClientAuthenticator();
        }
    }
}