public class ProviderManager implements AuthenticationManager, MessageSourceAware, InitializingBean {    private static final Log logger = LogFactory.getLog(ProviderManager.class);//记录器    private AuthenticationEventPublisher eventPublisher;//验证事件发布器    private List
     
       providers;//认证提供者    protected MessageSourceAccessor messages; //消息源访问器    private AuthenticationManager parent; //父 认证管理器    private boolean eraseCredentialsAfterAuthentication; //擦除安全认证    public ProviderManager(List
      
        providers) {//服务管理器        this(providers, (AuthenticationManager)null);    }    public ProviderManager(List
       
         providers, AuthenticationManager parent) {        this.eventPublisher = new ProviderManager.NullEventPublisher();//事件发布        this.providers = Collections.emptyList();//赋一个空集合        this.messages = SpringSecurityMessageSource.getAccessor();        this.eraseCredentialsAfterAuthentication = true;        Assert.notNull(providers, "providers list cannot be null");        this.providers = providers;        this.parent = parent;        this.checkState();    }    public void afterPropertiesSet() throws Exception {        this.checkState();    }    private void checkState() {        if (this.parent == null && this.providers.isEmpty()) {            throw new IllegalArgumentException("A parent AuthenticationManager or a list of AuthenticationProviders is required");        }    }    public Authentication authenticate(Authentication authentication) throws AuthenticationException {        Class
         toTest = authentication.getClass();        AuthenticationException lastException = null;        Authentication result = null;        boolean debug = logger.isDebugEnabled();        Iterator var6 = this.getProviders().iterator();        while(var6.hasNext()) {            AuthenticationProvider provider = (AuthenticationProvider)var6.next();            if (provider.supports(toTest)) {                if (debug) {                    logger.debug("Authentication attempt using " + provider.getClass().getName());                }                try {                    result = provider.authenticate(authentication);                    if (result != null) {//复制详情                        this.copyDetails(authentication, result);                        break;                    }                } catch (AccountStatusException var11) {//账户状态异常                    this.prepareException(var11, authentication);                    throw var11;                } catch (InternalAuthenticationServiceException var12) {//内部认证服务异常                    this.prepareException(var12, authentication);                    throw var12;                } catch (AuthenticationException var13) {//认证异常                    lastException = var13;                }            }        }        if (result == null && this.parent != null) {            try {                result = this.parent.authenticate(authentication);            } catch (ProviderNotFoundException var9) {//服务未找到异常                ;            } catch (AuthenticationException var10) {//认证异常                lastException = var10;            }        }        if (result != null) {            if (this.eraseCredentialsAfterAuthentication && result instanceof CredentialsContainer) {//擦除密码                ((CredentialsContainer)result).eraseCredentials();            }            this.eventPublisher.publishAuthenticationSuccess(result);//事件发布程序。发布认证成功            return result;        } else {            if (lastException == null) {                lastException = new ProviderNotFoundException(this.messages.getMessage("ProviderManager.providerNotFound", new Object[]{toTest.getName()}, "No AuthenticationProvider found for {0}"));            }            this.prepareException((AuthenticationException)lastException, authentication);//事件发布程序，发布认证失败            throw lastException;        }    }    private void prepareException(AuthenticationException ex, Authentication auth) {//准备异常        this.eventPublisher.publishAuthenticationFailure(ex, auth);    }    private void copyDetails(Authentication source, Authentication dest) {//复制详情        if (dest instanceof AbstractAuthenticationToken && dest.getDetails() == null) {            AbstractAuthenticationToken token = (AbstractAuthenticationToken)dest;            token.setDetails(source.getDetails());        }    }    public List
        
          getProviders() {//get 认证服务        return this.providers;    }    public void setMessageSource(MessageSource messageSource) {//set信息源        this.messages = new MessageSourceAccessor(messageSource);    }    public void setAuthenticationEventPublisher(AuthenticationEventPublisher eventPublisher) {//set 认证事件发布        Assert.notNull(eventPublisher, "AuthenticationEventPublisher cannot be null");        this.eventPublisher = eventPublisher;    }    public void setEraseCredentialsAfterAuthentication(boolean eraseSecretData) {//set是否测出密码在认证后        this.eraseCredentialsAfterAuthentication = eraseSecretData;    }    public boolean isEraseCredentialsAfterAuthentication() {//是否擦除密码在认证后        return this.eraseCredentialsAfterAuthentication;    }    private static final class NullEventPublisher implements AuthenticationEventPublisher { //认证事件发布        private NullEventPublisher() {//没有事件发布        }        public void publishAuthenticationFailure(AuthenticationException exception, Authentication authentication) {//发布认证失败        }        public void publishAuthenticationSuccess(Authentication authentication) {//发布认证成功        }    }}