Java 类org.apache.http.auth.AuthSchemeRegistry 实例源码

public ProxyClient(final HttpParams params) {
    super();
    if (params == null) {
        throw new IllegalArgumentException("HTTP parameters may not be null");
    }
    this.httpProcessor = new ImmutableHttpProcessor(new HttpRequestInterceptor[] {
            new RequestContent(),
            new RequestTargetHost(),
            new RequestClientConnControl(),
            new RequestUserAgent(),
            new RequestProxyAuthentication()
    } );
    this.requestExec = new HttpRequestExecutor();
    this.proxyAuthStrategy = new ProxyAuthenticationStrategy();
    this.authenticator = new HttpAuthenticator();
    this.proxyAuthState = new AuthState();
    this.authSchemeRegistry = new AuthSchemeRegistry();
    this.authSchemeRegistry.register(AuthPolicy.BASIC, new BasicSchemeFactory());
    this.authSchemeRegistry.register(AuthPolicy.DIGEST, new DigestSchemeFactory());
    this.authSchemeRegistry.register(AuthPolicy.NTLM, new NTLMSchemeFactory());
    this.authSchemeRegistry.register(AuthPolicy.SPNEGO, new SPNegoSchemeFactory());
    this.authSchemeRegistry.register(AuthPolicy.KERBEROS, new KerberosSchemeFactory());
    this.reuseStrategy = new DefaultConnectionReuseStrategy();
    this.params = params;
}

protected AuthSchemeRegistry createAuthSchemeRegistry() {
    AuthSchemeRegistry registry = new AuthSchemeRegistry();
    registry.register(
            AuthPolicy.BASIC,
            new BasicSchemeFactory());
    registry.register(
            AuthPolicy.DIGEST,
            new DigestSchemeFactory());
    registry.register(
            AuthPolicy.NTLM,
            new NTLMSchemeFactory());
    registry.register(
            AuthPolicy.SPNEGO,
            new SPNegoSchemeFactory());
    registry.register(
            AuthPolicy.KERBEROS,
            new KerberosSchemeFactory());
    return registry;
}

/**
 * @since 4.3
 */
public ProxyClient(
        final HttpConnectionFactory<HttpRoute, ManagedHttpClientConnection> connFactory,
        final ConnectionConfig connectionConfig,
        final RequestConfig requestConfig) {
    super();
    this.connFactory = connFactory != null ? connFactory : ManagedHttpClientConnectionFactory.INSTANCE;
    this.connectionConfig = connectionConfig != null ? connectionConfig : ConnectionConfig.DEFAULT;
    this.requestConfig = requestConfig != null ? requestConfig : RequestConfig.DEFAULT;
    this.httpProcessor = new ImmutableHttpProcessor(
            new RequestTargetHostHC4(), new RequestClientConnControl(), new RequestUserAgentHC4());
    this.requestExec = new HttpRequestExecutor();
    this.proxyAuthStrategy = new ProxyAuthenticationStrategy();
    this.authenticator = new HttpAuthenticator();
    this.proxyAuthState = new AuthStateHC4();
    this.authSchemeRegistry = new AuthSchemeRegistry();
    this.authSchemeRegistry.register(AuthSchemes.BASIC, new BasicSchemeFactoryHC4());
    this.authSchemeRegistry.register(AuthSchemes.DIGEST, new DigestSchemeFactoryHC4());
    this.authSchemeRegistry.register(AuthSchemes.NTLM, new NTLMSchemeFactory());
    this.reuseStrategy = new DefaultConnectionReuseStrategyHC4();
}

protected AuthSchemeRegistry createAuthSchemeRegistry() {
    final AuthSchemeRegistry registry = new AuthSchemeRegistry();
    registry.register(
            AuthPolicy.BASIC,
            new BasicSchemeFactory());
    registry.register(
            AuthPolicy.DIGEST,
            new DigestSchemeFactory());
    registry.register(
            AuthPolicy.NTLM,
            new NTLMSchemeFactory());
    registry.register(
            AuthPolicy.SPNEGO,
            new SPNegoSchemeFactory());
    registry.register(
            AuthPolicy.KERBEROS,
            new KerberosSchemeFactory());
    return registry;
}

/**
 * @since 4.3
 */
public ProxyClient(
        final HttpConnectionFactory<HttpRoute, ManagedHttpClientConnection> connFactory,
        final ConnectionConfig connectionConfig,
        final RequestConfig requestConfig) {
    super();
    this.connFactory = connFactory != null ? connFactory : ManagedHttpClientConnectionFactory.INSTANCE;
    this.connectionConfig = connectionConfig != null ? connectionConfig : ConnectionConfig.DEFAULT;
    this.requestConfig = requestConfig != null ? requestConfig : RequestConfig.DEFAULT;
    this.httpProcessor = new ImmutableHttpProcessor(
            new RequestTargetHost(), new RequestClientConnControl(), new RequestUserAgent());
    this.requestExec = new HttpRequestExecutor();
    this.proxyAuthStrategy = new ProxyAuthenticationStrategy();
    this.authenticator = new HttpAuthenticator();
    this.proxyAuthState = new AuthState();
    this.authSchemeRegistry = new AuthSchemeRegistry();
    this.authSchemeRegistry.register(AuthSchemes.BASIC, new BasicSchemeFactory());
    this.authSchemeRegistry.register(AuthSchemes.DIGEST, new DigestSchemeFactory());
    this.authSchemeRegistry.register(AuthSchemes.NTLM, new NTLMSchemeFactory());
    this.authSchemeRegistry.register(AuthSchemes.SPNEGO, new SPNegoSchemeFactory());
    this.authSchemeRegistry.register(AuthSchemes.KERBEROS, new KerberosSchemeFactory());
    this.reuseStrategy = new DefaultConnectionReuseStrategy();
}

/**
 * @since 4.3
 */
public ProxyClient(
        final HttpConnectionFactory<HttpRoute, ManagedHttpClientConnection> connFactory,
        final ConnectionConfig connectionConfig,
        final RequestConfig requestConfig) {
    super();
    this.connFactory = connFactory != null ? connFactory : ManagedHttpClientConnectionFactory.INSTANCE;
    this.connectionConfig = connectionConfig != null ? connectionConfig : ConnectionConfig.DEFAULT;
    this.requestConfig = requestConfig != null ? requestConfig : RequestConfig.DEFAULT;
    this.httpProcessor = new ImmutableHttpProcessor(
            new RequestTargetHostHC4(), new RequestClientConnControl(), new RequestUserAgentHC4());
    this.requestExec = new HttpRequestExecutor();
    this.proxyAuthStrategy = new ProxyAuthenticationStrategy();
    this.authenticator = new HttpAuthenticator();
    this.proxyAuthState = new AuthStateHC4();
    this.authSchemeRegistry = new AuthSchemeRegistry();
    this.authSchemeRegistry.register(AuthSchemes.BASIC, new BasicSchemeFactoryHC4());
    this.authSchemeRegistry.register(AuthSchemes.DIGEST, new DigestSchemeFactoryHC4());
    this.authSchemeRegistry.register(AuthSchemes.NTLM, new NTLMSchemeFactory());
    this.reuseStrategy = new DefaultConnectionReuseStrategyHC4();
}

/**
 * @since 4.3
 */
public ProxyClient(
        final HttpConnectionFactory<HttpRoute, ManagedHttpClientConnection> connFactory,
        final ConnectionConfig connectionConfig,
        final RequestConfig requestConfig) {
    super();
    this.connFactory = connFactory != null ? connFactory : ManagedHttpClientConnectionFactory.INSTANCE;
    this.connectionConfig = connectionConfig != null ? connectionConfig : ConnectionConfig.DEFAULT;
    this.requestConfig = requestConfig != null ? requestConfig : RequestConfig.DEFAULT;
    this.httpProcessor = new ImmutableHttpProcessor(
            new RequestTargetHostHC4(), new RequestClientConnControl(), new RequestUserAgentHC4());
    this.requestExec = new HttpRequestExecutor();
    this.proxyAuthStrategy = new ProxyAuthenticationStrategy();
    this.authenticator = new HttpAuthenticator();
    this.proxyAuthState = new AuthStateHC4();
    this.authSchemeRegistry = new AuthSchemeRegistry();
    this.authSchemeRegistry.register(AuthSchemes.BASIC, new BasicSchemeFactoryHC4());
    this.authSchemeRegistry.register(AuthSchemes.DIGEST, new DigestSchemeFactoryHC4());
    this.authSchemeRegistry.register(AuthSchemes.NTLM, new NTLMSchemeFactory());
    this.reuseStrategy = new DefaultConnectionReuseStrategyHC4();
}

/**
 * If no auth scheme has been selected for the given context, consider each
 * of the preferred auth schemes and select the first one for which an
 * AuthScheme and matching Credentials are available.
 */
public void process(HttpRequest request, HttpContext context) throws HttpException, IOException {
    AuthState authState = (AuthState) context.getAttribute(ClientContext.TARGET_AUTH_STATE);
    if (authState != null && authState.getAuthScheme() != null) {
        return;
    }
    HttpHost target = (HttpHost) context.getAttribute(ExecutionContext.HTTP_TARGET_HOST);
    CredentialsProvider creds = (CredentialsProvider) context.getAttribute(ClientContext.CREDS_PROVIDER);
    AuthSchemeRegistry schemes = (AuthSchemeRegistry) context.getAttribute(ClientContext.AUTHSCHEME_REGISTRY);
    for (Object schemeName : (Iterable) context.getAttribute(ClientContext.AUTH_SCHEME_PREF)) {
        AuthScheme scheme = schemes.getAuthScheme(schemeName.toString(), request.getParams());
        if (scheme != null) {
            AuthScope targetScope = new AuthScope(target.getHostName(), target.getPort(), scheme.getRealm(), scheme
                    .getSchemeName());
            Credentials cred = creds.getCredentials(targetScope);
            if (cred != null) {
                authState.setAuthScheme(scheme);
                authState.setCredentials(cred);
                return;
            }
        }
    }
}

/**
 * If no auth scheme has been selected for the given context, consider each
 * of the preferred auth schemes and select the first one for which an
 * AuthScheme and matching Credentials are available.
 */
public void process(HttpRequest request, HttpContext context) throws HttpException, IOException {
    AuthState authState = (AuthState) context.getAttribute(ClientContext.TARGET_AUTH_STATE);
    if (authState != null && authState.getAuthScheme() != null) {
        return;
    }
    HttpHost target = (HttpHost) context.getAttribute(ExecutionContext.HTTP_TARGET_HOST);
    CredentialsProvider creds = (CredentialsProvider) context.getAttribute(ClientContext.CREDS_PROVIDER);
    AuthSchemeRegistry schemes = (AuthSchemeRegistry) context.getAttribute(ClientContext.AUTHSCHEME_REGISTRY);
    for (Object schemeName : (Iterable) context.getAttribute(ClientContext.AUTH_SCHEME_PREF)) {
        AuthScheme scheme = schemes.getAuthScheme(schemeName.toString(), request.getParams());
        if (scheme != null) {
            AuthScope targetScope = new AuthScope(target.getHostName(), target.getPort(), scheme.getRealm(), scheme
                    .getSchemeName());
            Credentials cred = creds.getCredentials(targetScope);
            if (cred != null) {
                authState.setAuthScheme(scheme);
                authState.setCredentials(cred);
                return;
            }
        }
    }
}

/**
 * If no auth scheme has been selected for the given context, consider each
 * of the preferred auth schemes and select the first one for which an
 * AuthScheme and matching Credentials are available.
 */
public void process(HttpRequest request, HttpContext context) throws HttpException, IOException {
    AuthState authState = (AuthState) context.getAttribute(ClientContext.TARGET_AUTH_STATE);
    if (authState != null && authState.getAuthScheme() != null) {
        return;
    }
    HttpHost target = (HttpHost) context.getAttribute(ExecutionContext.HTTP_TARGET_HOST);
    CredentialsProvider creds = (CredentialsProvider) context.getAttribute(ClientContext.CREDS_PROVIDER);
    AuthSchemeRegistry schemes = (AuthSchemeRegistry) context.getAttribute(ClientContext.AUTHSCHEME_REGISTRY);
    for (Object schemeName : (Iterable) context.getAttribute(ClientContext.AUTH_SCHEME_PREF)) {
        AuthScheme scheme = schemes.getAuthScheme(schemeName.toString(), request.getParams());
        if (scheme != null) {
            AuthScope targetScope = new AuthScope(target.getHostName(), target.getPort(), scheme.getRealm(), scheme
                    .getSchemeName());
            Credentials cred = creds.getCredentials(targetScope);
            if (cred != null) {
                authState.setAuthScheme(scheme);
                authState.setCredentials(cred);
                return;
            }
        }
    }
}

@Override
protected AuthSchemeRegistry createAuthSchemeRegistry() {
    AuthSchemeRegistry registry = new AuthSchemeRegistry(); 
    registry.register(
            AuthPolicy.BASIC, 
            new BasicSchemeFactory());
    registry.register(
            AuthPolicy.DIGEST, 
            new DigestSchemeFactory());
    return registry;
}

/**
 * If no auth scheme has been selected for the given context, consider each
 * of the preferred auth schemes and select the first one for which an
 * AuthScheme and matching Credentials are available.
 */
@SuppressWarnings("rawtypes")
public void process(HttpRequest request, HttpContext context)
        throws HttpException, IOException {
    AuthState authState = (AuthState) context
            .getAttribute(ClientContext.TARGET_AUTH_STATE);
    if (authState != null && authState.getAuthScheme() != null) {
        return;
    }
    HttpHost target = (HttpHost) context
            .getAttribute(ExecutionContext.HTTP_TARGET_HOST);
    CredentialsProvider creds = (CredentialsProvider) context
            .getAttribute(ClientContext.CREDS_PROVIDER);
    AuthSchemeRegistry schemes = (AuthSchemeRegistry) context
            .getAttribute(ClientContext.AUTHSCHEME_REGISTRY);
    for (Object schemeName : (Iterable) context
            .getAttribute(ClientContext.AUTH_SCHEME_PREF)) {
        AuthScheme scheme = schemes.getAuthScheme(schemeName.toString(),
                request.getParams());
        if (scheme != null) {
            AuthScope targetScope = new AuthScope(target.getHostName(),
                    target.getPort(), scheme.getRealm(),
                    scheme.getSchemeName());
            Credentials cred = creds.getCredentials(targetScope);
            if (cred != null) {
                authState.setAuthScheme(scheme);
                authState.setCredentials(cred);
                return;
            }
        }
    }
}

public void setAuthSchemeRegistry(final AuthSchemeRegistry registry) {
    this.context.setAttribute(AUTHSCHEME_REGISTRY, registry);
}

public AuthSchemeRegistry getAuthSchemeRegistry() {
    return this.authSchemeRegistry;
}

public synchronized final AuthSchemeRegistry getAuthSchemes() {
    if (supportedAuthSchemes == null) {
        supportedAuthSchemes = createAuthSchemeRegistry();
    }
    return supportedAuthSchemes;
}

public synchronized void setAuthSchemes(final AuthSchemeRegistry registry) {
    supportedAuthSchemes = registry;
}

public Queue<AuthOption> select(
        final Map<String, Header> challenges,
        final HttpHost authhost,
        final HttpResponse response,
        final HttpContext context) throws MalformedChallengeException {
    if (challenges == null) {
        throw new IllegalArgumentException("Map of auth challenges may not be null");
    }
    if (authhost == null) {
        throw new IllegalArgumentException("Host may not be null");
    }
    if (response == null) {
        throw new IllegalArgumentException("HTTP response may not be null");
    }
    if (context == null) {
        throw new IllegalArgumentException("HTTP context may not be null");
    }

    Queue<AuthOption> options = new LinkedList<AuthOption>();
    AuthSchemeRegistry registry = (AuthSchemeRegistry) context.getAttribute(
            ClientContext.AUTHSCHEME_REGISTRY);
    if (registry == null) {
        this.log.debug("Auth scheme registry not set in the context");
        return options;
    }
    CredentialsProvider credsProvider = (CredentialsProvider) context.getAttribute(
            ClientContext.CREDS_PROVIDER);
    if (credsProvider == null) {
        this.log.debug("Credentials provider not set in the context");
        return options;
    }

    @SuppressWarnings("unchecked")
    List<String> authPrefs = (List<String>) response.getParams().getParameter(this.prefParamName);
    if (authPrefs == null) {
        authPrefs = DEFAULT_SCHEME_PRIORITY;
    }
    if (this.log.isDebugEnabled()) {
        this.log.debug("Authentication schemes in the order of preference: " + authPrefs);
    }

    for (String id: authPrefs) {
        Header challenge = challenges.get(id.toLowerCase(Locale.US));
        if (challenge != null) {
            try {
                AuthScheme authScheme = registry.getAuthScheme(id, response.getParams());
                authScheme.processChallenge(challenge);

                AuthScope authScope = new AuthScope(
                        authhost.getHostName(),
                        authhost.getPort(),
                        authScheme.getRealm(),
                        authScheme.getSchemeName());

                Credentials credentials = credsProvider.getCredentials(authScope);
                if (credentials != null) {
                    options.add(new AuthOption(authScheme, credentials));
                }
            } catch (IllegalStateException e) {
                if (this.log.isWarnEnabled()) {
                    this.log.warn("Authentication scheme " + id + " not supported");
                    // Try again
                }
            }
        } else {
            if (this.log.isDebugEnabled()) {
                this.log.debug("Challenge for " + id + " authentication scheme not available");
                // Try again
            }
        }
    }
    return options;
}

public AuthScheme selectScheme(
        final Map<String, Header> challenges,
        final HttpResponse response,
        final HttpContext context) throws AuthenticationException {

    AuthSchemeRegistry registry = (AuthSchemeRegistry) context.getAttribute(
            ClientContext.AUTHSCHEME_REGISTRY);
    if (registry == null) {
        throw new IllegalStateException("AuthScheme registry not set in HTTP context");
    }

    Collection<String> authPrefs = getAuthPreferences(response, context);
    if (authPrefs == null) {
        authPrefs = DEFAULT_SCHEME_PRIORITY;
    }

    if (this.log.isDebugEnabled()) {
        this.log.debug("Authentication schemes in the order of preference: "
            + authPrefs);
    }

    AuthScheme authScheme = null;
    for (String id: authPrefs) {
        Header challenge = challenges.get(id.toLowerCase(Locale.ENGLISH));

        if (challenge != null) {
            if (this.log.isDebugEnabled()) {
                this.log.debug(id + " authentication scheme selected");
            }
            try {
                authScheme = registry.getAuthScheme(id, response.getParams());
                break;
            } catch (IllegalStateException e) {
                if (this.log.isWarnEnabled()) {
                    this.log.warn("Authentication scheme " + id + " not supported");
                    // Try again
                }
            }
        } else {
            if (this.log.isDebugEnabled()) {
                this.log.debug("Challenge for " + id + " authentication scheme not available");
                // Try again
            }
        }
    }
    if (authScheme == null) {
        // If none selected, something is wrong
        throw new AuthenticationException(
            "Unable to respond to any of these challenges: "
                + challenges);
    }
    return authScheme;
}

/**
 * @deprecated (4.3) do not use.
 */
@Deprecated
public AuthSchemeRegistry getAuthSchemeRegistry() {
    return this.authSchemeRegistry;
}

public void setAuthSchemeRegistry(final AuthSchemeRegistry registry) {
    this.context.setAttribute(AUTHSCHEME_REGISTRY, registry);
}

public synchronized final AuthSchemeRegistry getAuthSchemes() {
    if (supportedAuthSchemes == null) {
        supportedAuthSchemes = createAuthSchemeRegistry();
    }
    return supportedAuthSchemes;
}

public synchronized void setAuthSchemes(final AuthSchemeRegistry registry) {
    supportedAuthSchemes = registry;
}

@Override
public AuthScheme selectScheme(
        final Map<String, Header> challenges,
        final HttpResponse response,
        final HttpContext context) throws AuthenticationException {

    final AuthSchemeRegistry registry = (AuthSchemeRegistry) context.getAttribute(
            ClientContext.AUTHSCHEME_REGISTRY);
    Asserts.notNull(registry, "AuthScheme registry");
    Collection<String> authPrefs = getAuthPreferences(response, context);
    if (authPrefs == null) {
        authPrefs = DEFAULT_SCHEME_PRIORITY;
    }

    if (this.log.isDebugEnabled()) {
        this.log.debug("Authentication schemes in the order of preference: "
            + authPrefs);
    }

    AuthScheme authScheme = null;
    for (final String id: authPrefs) {
        final Header challenge = challenges.get(id.toLowerCase(Locale.ENGLISH));

        if (challenge != null) {
            if (this.log.isDebugEnabled()) {
                this.log.debug(id + " authentication scheme selected");
            }
            try {
                authScheme = registry.getAuthScheme(id, response.getParams());
                break;
            } catch (final IllegalStateException e) {
                if (this.log.isWarnEnabled()) {
                    this.log.warn("Authentication scheme " + id + " not supported");
                    // Try again
                }
            }
        } else {
            if (this.log.isDebugEnabled()) {
                this.log.debug("Challenge for " + id + " authentication scheme not available");
                // Try again
            }
        }
    }
    if (authScheme == null) {
        // If none selected, something is wrong
        throw new AuthenticationException(
            "Unable to respond to any of these challenges: "
                + challenges);
    }
    return authScheme;
}

/**
 * @deprecated (4.3) do not use.
 */
@Deprecated
public AuthSchemeRegistry getAuthSchemeRegistry() {
    return this.authSchemeRegistry;
}

/**
 * @deprecated (4.3) do not use.
 */
@Deprecated
public AuthSchemeRegistry getAuthSchemeRegistry() {
    return this.authSchemeRegistry;
}

public void configure(DefaultHttpClient httpClient, SolrParams config) {
  super.configure(httpClient, config);

  // Begin change for SDC-2962
  // Instead of checking existence of JAAS file, do the following if solr kerberos is enabled
  //if (System.getProperty(LOGIN_CONFIG_PROP) != null) {
    //String configValue = System.getProperty(LOGIN_CONFIG_PROP);

    //if (configValue != null) {
     // logger.info("Setting up SPNego auth with config: " + configValue);
      final String useSubjectCredsProp = "javax.security.auth.useSubjectCredsOnly";
      String useSubjectCredsVal = System.getProperty(useSubjectCredsProp);

      // "javax.security.auth.useSubjectCredsOnly" should be false so that the underlying
      // authentication mechanism can load the credentials from the JAAS configuration.
      if (useSubjectCredsVal == null) {
        System.setProperty(useSubjectCredsProp, "false");
      }
      else if (!useSubjectCredsVal.toLowerCase(Locale.ROOT).equals("false")) {
        // Don't overwrite the prop value if it's already been written to something else,
        // but log because it is likely the Credentials won't be loaded correctly.
        logger.warn("System Property: " + useSubjectCredsProp + " set to: " + useSubjectCredsVal
            + " not false.  SPNego authentication may not be successful.");
      }

      // Change for SDC-2962
      //javax.security.auth.login.Configuration.setConfiguration(jaasConfig);
      //Enable only SPNEGO authentication scheme.
      AuthSchemeRegistry registry = new AuthSchemeRegistry();
      registry.register(AuthSchemes.SPNEGO, new SPNegoSchemeFactory(true, false));
      httpClient.setAuthSchemes(registry);
      // Get the credentials from the JAAS configuration rather than here
      Credentials useJaasCreds = new Credentials() {
        public String getPassword() {
          return null;
        }
        public Principal getUserPrincipal() {
          return null;
        }
      };

      SolrPortAwareCookieSpecFactory cookieFactory = new SolrPortAwareCookieSpecFactory();
      httpClient.getCookieSpecs().register(cookieFactory.POLICY_NAME, cookieFactory);
      httpClient.getParams().setParameter(ClientPNames.COOKIE_POLICY, cookieFactory.POLICY_NAME);

      httpClient.getCredentialsProvider().setCredentials(AuthScope.ANY, useJaasCreds);

      httpClient.addRequestInterceptor(bufferedEntityInterceptor);
    //} else {
      //httpClient.getCredentialsProvider().clear();
    //}
 // }
}

public void setAuthSchemeRegistry(final AuthSchemeRegistry registry) {
    this.context.setAttribute(AUTHSCHEME_REGISTRY, registry);
}

public synchronized final AuthSchemeRegistry getAuthSchemes() {
    if (supportedAuthSchemes == null) {
        supportedAuthSchemes = createAuthSchemeRegistry();
    }
    return supportedAuthSchemes;
}

public synchronized void setAuthSchemes(final AuthSchemeRegistry authSchemeRegistry) {
    supportedAuthSchemes = authSchemeRegistry;
}

public AuthScheme selectScheme(
        final Map<String, Header> challenges, 
        final HttpResponse response,
        final HttpContext context) throws AuthenticationException {

    AuthSchemeRegistry registry = (AuthSchemeRegistry) context.getAttribute(
            ClientContext.AUTHSCHEME_REGISTRY);
    if (registry == null) {
        throw new IllegalStateException("AuthScheme registry not set in HTTP context");
    }

    @SuppressWarnings("unchecked")
    Collection<String> authPrefs = (Collection<String>) context.getAttribute(
            ClientContext.AUTH_SCHEME_PREF);
    if (authPrefs == null) {
        authPrefs = getAuthPreferences();
    }

    if (this.log.isDebugEnabled()) {
        this.log.debug("Authentication schemes in the order of preference: " 
            + authPrefs);
    }

    AuthScheme authScheme = null;
    for (String id: authPrefs) {
        Header challenge = challenges.get(id.toLowerCase(Locale.ENGLISH)); 

        if (challenge != null) {
            if (this.log.isDebugEnabled()) {
                this.log.debug(id + " authentication scheme selected");
            }
            try {
                authScheme = registry.getAuthScheme(id, response.getParams());
                break;
            } catch (IllegalStateException e) {
                if (this.log.isWarnEnabled()) {
                    this.log.warn("Authentication scheme " + id + " not supported");
                    // Try again
                }
            }
        } else {
            if (this.log.isDebugEnabled()) {
                this.log.debug("Challenge for " + id + " authentication scheme not available");
                // Try again
            }
        }
    }
    if (authScheme == null) {
        // If none selected, something is wrong
        throw new AuthenticationException(
            "Unable to respond to any of these challenges: "
                + challenges);
    }
    return authScheme;
}

/**
 * @deprecated (4.3) do not use.
 */
@Deprecated
public AuthSchemeRegistry getAuthSchemeRegistry() {
    return this.authSchemeRegistry;
}

protected abstract AuthSchemeRegistry createAuthSchemeRegistry();