org.springframework.context.expression.BeanFactoryResolver Java Examples

/**
 * 创建SpEL执行上下文
 *
 * @param rootObject
 *            SpEL表达式根对象
 * @param context
 *            Beetl上下文对象
 * @return SpEL表达式执行上下文
 */
private EvaluationContext createEvaluationContext(Object rootObject, Context beetlContext) {
	StandardEvaluationContext context = new StandardEvaluationContext(rootObject);

	// 允许使用#context访问Beetl上下文
	context.setVariable("context", beetlContext);
	// 允许使用#global访问Beetl上下文的全局变量
	context.setVariable("global", beetlContext.globalVar);
	// 注册WebRender定义的全局变量
	context.setVariable("ctxPath", beetlContext.getGlobal("ctxPath"));
	context.setVariable("servlet", beetlContext.getGlobal("servlet"));
	context.setVariable("parameter", beetlContext.getGlobal("parameter"));
	context.setVariable("request", beetlContext.getGlobal("request"));
	context.setVariable("session", beetlContext.getGlobal("session"));
	// 允许使用属性格式访问Map
	context.addPropertyAccessor(new MapAccessor());
	// 允许访问Spring容器Bean
	context.setBeanResolver(new BeanFactoryResolver(applicationContext));

	return context;
}
 

@Test
public void evaluateToString() {
    // given
    StandardEvaluationContext evaluationContext = new StandardEvaluationContext();
    evaluationContext.setBeanResolver(new BeanFactoryResolver(applicationContext));
    ExpressionEvaluator expressionEvaluator = new ExpressionEvaluator(expressionParser, evaluationContext);

    String string = "toString()";
    String string2 = "#this";
    String string3 = "#root";
    Argument argument = new Argument();
    // when
    Object result = expressionEvaluator.evaluate(string, argument);
    Object result2 = expressionEvaluator.evaluate(string2, argument);
    Object result3 = expressionEvaluator.evaluate(string3, argument);
    // then
    assertThat(result, is("!"));
    assertThat(result2, is(argument));
    assertThat(result3, is(argument));
}
 

private List<MetricTagResult> getMetricTags(ExpressionParser expressionParser, 
		ConfigurableBeanFactory beanFactory,
		FilterConfiguration<R> filterConfig, 
		R servletRequest) {
	
	List<MetricTagResult> metricTagResults = filterConfig
		.getMetrics().getTags()
		.stream()
		.map( (metricMetaTag) -> {
			String expression = metricMetaTag.getExpression();
			if(StringUtils.isEmpty(expression)) {
				throw new MissingMetricTagExpressionException(metricMetaTag.getKey());
			}
			StandardEvaluationContext context = new StandardEvaluationContext();
			context.setBeanResolver(new BeanFactoryResolver(beanFactory));
			//TODO performance problem - how can the request object reused in the expression without setting it as a rootObject
			Expression expr = expressionParser.parseExpression(expression); 
			final String value = expr.getValue(context, servletRequest, String.class);
			
			return new MetricTagResult(metricMetaTag.getKey(), value, metricMetaTag.getTypes());
	}).collect(toList());
	if(metricTagResults == null) {
		metricTagResults = new ArrayList<>();
	}
	return metricTagResults;
}
 

/**
 * Creates the key filter lambda which is responsible to decide how the rate limit will be performed. The key
 * is the unique identifier like an IP address or a username.
 * 
 * @param url is used to generated a unique cache key
 * @param rateLimit the {@link RateLimit} configuration which holds the skip condition string
 * @param expressionParser is used to evaluate the expression if the filter key type is EXPRESSION.
 * @param beanFactory used to get full access to all java beans in the SpEl
 * @return should not been null. If no filter key type is matching a plain 1 is returned so that all requests uses the same key.
 */
public KeyFilter<R> getKeyFilter(String url, RateLimit rateLimit, ExpressionParser expressionParser, BeanFactory beanFactory) {
	
	String expression = rateLimit.getExpression();
	if(StringUtils.isEmpty(expression)) {
		throw new MissingKeyFilterExpressionException();
	}
	StandardEvaluationContext context = new StandardEvaluationContext();
	context.setBeanResolver(new BeanFactoryResolver(beanFactory));
	return  (request) -> {
		//TODO performance problem - how can the request object reused in the expression without setting it as a rootObject
		Expression expr = expressionParser.parseExpression(rateLimit.getExpression()); 
		final String value = expr.getValue(context, request, String.class);
		return url + "-" + value;
	};

	
}
 

private static Object getValue(SpelExpressionParser parser, BeanFactory beanFactory,
                               String entryValue) {
    Object value;
    String rawValue = entryValue;
    if (rawValue != null) {
        rawValue = rawValue.trim();
    }
    if (rawValue != null && rawValue.startsWith("#{") && entryValue.endsWith("}")) {
        // assume it's spel
        StandardEvaluationContext context = new StandardEvaluationContext();
        context.setBeanResolver(new BeanFactoryResolver(beanFactory));
        Expression expression = parser.parseExpression(entryValue,
                new TemplateParserContext());
        context.lookupVariable("api");
        value = expression.getValue(context);
    } else {
        value = entryValue;
    }
    return value;
}
 

/**
 * Create an {@link EvaluationContext}.
 * @param caches the current caches
 * @param method the method
 * @param args the method arguments
 * @param target the target object
 * @param targetClass the target class
 * @param result the return value (can be {@code null}) or
 * {@link #NO_RESULT} if there is no return at this time
 * @return the evaluation context
 */
public EvaluationContext createEvaluationContext(Collection<? extends Cache> caches,
		Method method, Object[] args, Object target, Class<?> targetClass, Method targetMethod,
		@Nullable Object result, @Nullable BeanFactory beanFactory) {

	CacheExpressionRootObject rootObject = new CacheExpressionRootObject(
			caches, method, args, target, targetClass);
	CacheEvaluationContext evaluationContext = new CacheEvaluationContext(
			rootObject, targetMethod, args, getParameterNameDiscoverer());
	if (result == RESULT_UNAVAILABLE) {
		evaluationContext.addUnavailableVariable(RESULT_VARIABLE);
	}
	else if (result != NO_RESULT) {
		evaluationContext.setVariable(RESULT_VARIABLE, result);
	}
	if (beanFactory != null) {
		evaluationContext.setBeanResolver(new BeanFactoryResolver(beanFactory));
	}
	return evaluationContext;
}
 

/**
 * Create an {@link EvaluationContext}.
 * @param caches the current caches
 * @param method the method
 * @param args the method arguments
 * @param target the target object
 * @param targetClass the target class
 * @param result the return value (can be {@code null}) or
 * {@link #NO_RESULT} if there is no return at this time
 * @return the evaluation context
 */
public EvaluationContext createEvaluationContext(Collection<? extends Cache> caches,
		Method method, Object[] args, Object target, Class<?> targetClass, Object result,
		BeanFactory beanFactory) {

	CacheExpressionRootObject rootObject = new CacheExpressionRootObject(
			caches, method, args, target, targetClass);
	Method targetMethod = getTargetMethod(targetClass, method);
	CacheEvaluationContext evaluationContext = new CacheEvaluationContext(
			rootObject, targetMethod, args, getParameterNameDiscoverer());
	if (result == RESULT_UNAVAILABLE) {
		evaluationContext.addUnavailableVariable(RESULT_VARIABLE);
	}
	else if (result != NO_RESULT) {
		evaluationContext.setVariable(RESULT_VARIABLE, result);
	}
	if (beanFactory != null) {
		evaluationContext.setBeanResolver(new BeanFactoryResolver(beanFactory));
	}
	return evaluationContext;
}
 

static Object getValue(SpelExpressionParser parser, BeanFactory beanFactory,
		String entryValue) {
	Object value;
	String rawValue = entryValue;
	if (rawValue != null) {
		rawValue = rawValue.trim();
	}
	if (rawValue != null && rawValue.startsWith("#{") && entryValue.endsWith("}")) {
		// assume it's spel
		StandardEvaluationContext context = new StandardEvaluationContext();
		context.setBeanResolver(new BeanFactoryResolver(beanFactory));
		Expression expression = parser.parseExpression(entryValue,
				new TemplateParserContext());
		value = expression.getValue(context);
	}
	else {
		value = entryValue;
	}
	return value;
}
 

private QueryMethodEvaluationContextProvider delegateContextProvider(
		QueryMethodEvaluationContextProvider evaluationContextProvider) {
	return new QueryMethodEvaluationContextProvider() {
		@Override
		public <T extends Parameters<?, ?>> EvaluationContext getEvaluationContext(
				T parameters, Object[] parameterValues) {
			StandardEvaluationContext evaluationContext = (StandardEvaluationContext)
					evaluationContextProvider
					.getEvaluationContext(parameters, parameterValues);
			evaluationContext.setRootObject(
					DatastoreRepositoryFactory.this.applicationContext);
			evaluationContext.addPropertyAccessor(new BeanFactoryAccessor());
			evaluationContext.setBeanResolver(new BeanFactoryResolver(
					DatastoreRepositoryFactory.this.applicationContext));
			return evaluationContext;
		}
	};
}
 

private QueryMethodEvaluationContextProvider delegateContextProvider(
		QueryMethodEvaluationContextProvider evaluationContextProvider) {
	return new QueryMethodEvaluationContextProvider() {
		@Override
		public <T extends Parameters<?, ?>> EvaluationContext getEvaluationContext(
				T parameters, Object[] parameterValues) {
			StandardEvaluationContext evaluationContext = (StandardEvaluationContext) evaluationContextProvider
					.getEvaluationContext(parameters, parameterValues);
			evaluationContext
					.setRootObject(SpannerRepositoryFactory.this.applicationContext);
			evaluationContext.addPropertyAccessor(new BeanFactoryAccessor());
			evaluationContext.setBeanResolver(new BeanFactoryResolver(
					SpannerRepositoryFactory.this.applicationContext));
			return evaluationContext;
		}
	};
}
 

/**
 * Create an {@link EvaluationContext}.
 * @param caches the current caches
 * @param method the method
 * @param args the method arguments
 * @param target the target object
 * @param targetClass the target class
 * @param result the return value (can be {@code null}) or
 * {@link #NO_RESULT} if there is no return at this time
 * @return the evaluation context
 */
public EvaluationContext createEvaluationContext(Collection<? extends Cache> caches,
		Method method, Object[] args, Object target, Class<?> targetClass, Method targetMethod,
		@Nullable Object result, @Nullable BeanFactory beanFactory) {

	CacheExpressionRootObject rootObject = new CacheExpressionRootObject(
			caches, method, args, target, targetClass);
	CacheEvaluationContext evaluationContext = new CacheEvaluationContext(
			rootObject, targetMethod, args, getParameterNameDiscoverer());
	if (result == RESULT_UNAVAILABLE) {
		evaluationContext.addUnavailableVariable(RESULT_VARIABLE);
	}
	else if (result != NO_RESULT) {
		evaluationContext.setVariable(RESULT_VARIABLE, result);
	}
	if (beanFactory != null) {
		evaluationContext.setBeanResolver(new BeanFactoryResolver(beanFactory));
	}
	return evaluationContext;
}
 

@Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {

	context.addPropertyAccessor(new BeanFactoryAccessor());
	context.setBeanResolver(new BeanFactoryResolver(applicationContext));
	context.setRootObject(applicationContext);
}
 

/**
 * Create the suitable {@link EvaluationContext} for the specified event handling
 * on the specified method.
 */
public EvaluationContext createEvaluationContext(ApplicationEvent event, Class<?> targetClass,
		Method method, Object[] args, BeanFactory beanFactory) {

	Method targetMethod = getTargetMethod(targetClass, method);
	EventExpressionRootObject root = new EventExpressionRootObject(event, args);
	MethodBasedEvaluationContext evaluationContext = new MethodBasedEvaluationContext(
			root, targetMethod, args, getParameterNameDiscoverer());
	if (beanFactory != null) {
		evaluationContext.setBeanResolver(new BeanFactoryResolver(beanFactory));
	}
	return evaluationContext;
}
 

@Override
public void setApplicationContext(ApplicationContext applicationContext)
		throws BeansException {
	this.context.addPropertyAccessor(new BeanFactoryAccessor());
	this.context.setBeanResolver(new BeanFactoryResolver(applicationContext));
	this.context.setRootObject(applicationContext);
}
 

private EvaluationContext createEvaluationContext(PageContext pageContext) {
	StandardEvaluationContext context = new StandardEvaluationContext();
	context.addPropertyAccessor(new JspPropertyAccessor(pageContext));
	context.addPropertyAccessor(new MapAccessor());
	context.addPropertyAccessor(new EnvironmentAccessor());
	context.setBeanResolver(new BeanFactoryResolver(getRequestContext().getWebApplicationContext()));
	ConversionService conversionService = getConversionService(pageContext);
	if (conversionService != null) {
		context.setTypeConverter(new StandardTypeConverter(conversionService));
	}
	return context;
}
 

/**
 * Creates the lambda for the execute condition which will be evaluated on each request.
 * 
 * @param rateLimit the {@link RateLimit} configuration which holds the execute condition string
 * @param expressionParser is used to evaluate the execution expression
 * @param beanFactory used to get full access to all java beans in the SpEl
 * @return the lamdba condition which will be evaluated lazy - null if there is no condition available.
 */
public Condition<R> executeCondition(RateLimit rateLimit, ExpressionParser expressionParser, BeanFactory beanFactory) {
	StandardEvaluationContext context = new StandardEvaluationContext();
	context.setBeanResolver(new BeanFactoryResolver(beanFactory));
	
	if(rateLimit.getExecuteCondition() != null) {
		return (request) -> {
			Expression expr = expressionParser.parseExpression(rateLimit.getExecuteCondition()); 
			Boolean value = expr.getValue(context, request, Boolean.class);
			return value;
		};
	}
	return null;
}
 

/**
 * Creates the lambda for the skip condition which will be evaluated on each request
 * 
 * @param rateLimit the {@link RateLimit} configuration which holds the skip condition string
 * @param expressionParser is used to evaluate the skip expression
 * @param beanFactory used to get full access to all java beans in the SpEl
 * @return the lamdba condition which will be evaluated lazy - null if there is no condition available.
 */
public Condition<R> skipCondition(RateLimit rateLimit, ExpressionParser expressionParser, BeanFactory beanFactory) {
	StandardEvaluationContext context = new StandardEvaluationContext();
	context.setBeanResolver(new BeanFactoryResolver(beanFactory));
	
	if(rateLimit.getSkipCondition() != null) {
		return  (request) -> {
			Expression expr = expressionParser.parseExpression(rateLimit.getSkipCondition()); 
			Boolean value = expr.getValue(context, request, Boolean.class);
			return value;
		};
	}
	return null;
}
 

private EvaluationContext createEvaluationContext(PageContext pageContext) {
	StandardEvaluationContext context = new StandardEvaluationContext();
	context.addPropertyAccessor(new JspPropertyAccessor(pageContext));
	context.addPropertyAccessor(new MapAccessor());
	context.addPropertyAccessor(new EnvironmentAccessor());
	context.setBeanResolver(new BeanFactoryResolver(getRequestContext().getWebApplicationContext()));
	ConversionService conversionService = getConversionService(pageContext);
	if (conversionService != null) {
		context.setTypeConverter(new StandardTypeConverter(conversionService));
	}
	return context;
}
 

@Override
public void setApplicationContext(final ApplicationContext applicationContext) throws BeansException {
	context.setRootObject(applicationContext);
	context.setBeanResolver(new BeanFactoryResolver(applicationContext));
	context.addPropertyAccessor(new BeanFactoryAccessor());
	eventPublisher = applicationContext;
	arango._setCursorInitializer(new ArangoCursorInitializer(converter, applicationContext));
}
 

public static void main(String[] args) {
    ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext();
    ctx.refresh();
    ExpressionParser parser = new SpelExpressionParser();
    StandardEvaluationContext context = new StandardEvaluationContext();
    context.setBeanResolver(new BeanFactoryResolver(ctx));
    Properties result = parser.parseExpression("@systemProperties").getValue(context, Properties.class);
    Assert.assertEquals(System.getProperties(), result);
}
 

/**
 * Create an {@link EvaluationContext}.
 *
 * @param method      the method
 * @param args        the method arguments
 * @param target      the target object
 * @param targetClass the target class
 * @return the evaluation context
 */
public EvaluationContext createContext(Method method, Object[] args, Object target, Class<?> targetClass, @Nullable BeanFactory beanFactory) {
	Method targetMethod = getTargetMethod(targetClass, method);
	MicaExpressionRootObject rootObject = new MicaExpressionRootObject(method, args, target, targetClass, targetMethod);
	MethodBasedEvaluationContext evaluationContext = new MethodBasedEvaluationContext(rootObject, targetMethod, args, getParameterNameDiscoverer());
	if (beanFactory != null) {
		evaluationContext.setBeanResolver(new BeanFactoryResolver(beanFactory));
	}
	return evaluationContext;
}
 

@Test
public void evaluateWithArgumentAndBeanReferencing() {
    // given
    StandardEvaluationContext evaluationContext = new StandardEvaluationContext();
    evaluationContext.setBeanResolver(new BeanFactoryResolver(applicationContext));
    ExpressionEvaluator expressionEvaluator = new ExpressionEvaluator(expressionParser, evaluationContext);

    String string = "@string.toString()";
    Argument argument = new Argument();
    // when
    Object result = expressionEvaluator.evaluate(string, argument);
    // then
    assertThat(result, is("bean string"));
}
 

@Test
public void evaluateWithBeanReferencing() {
    // given
    StandardEvaluationContext evaluationContext = new StandardEvaluationContext();
    evaluationContext.setBeanResolver(new BeanFactoryResolver(applicationContext));
    ExpressionEvaluator expressionEvaluator = new ExpressionEvaluator(expressionParser, evaluationContext);

    String string = "@string.toString()";
    // when
    Object result = expressionEvaluator.evaluate(string);
    // then
    assertThat(result, is("bean string"));
}
 

@Bean
@ConditionalOnMissingBean
public ExpressionEvaluator expressionEvaluator() {
    ExpressionParser expressionParser = new SpelExpressionParser(new SpelParserConfiguration(SpelCompilerMode.MIXED, null));
    StandardEvaluationContext evaluationContext = new StandardEvaluationContext();
    evaluationContext.setBeanResolver(new BeanFactoryResolver(applicationContext));
    return new ExpressionEvaluator(expressionParser, evaluationContext);
}
 

/**
 * 获取方法上的参数
 *
 * @param method 方法
 * @param args   变量
 * @return {SimpleEvaluationContext}
 */
private StandardEvaluationContext getEvaluationContext(Method method, Object[] args) {
	// 初始化Sp el表达式上下文，并设置 AuthFun
	StandardEvaluationContext context = new StandardEvaluationContext(new AuthFun());
	// 设置表达式支持spring bean
	context.setBeanResolver(new BeanFactoryResolver(applicationContext));
	for (int i = 0; i < args.length; i++) {
		// 读取方法参数
		MethodParameter methodParam = ClassUtil.getMethodParameter(method, i);
		// 设置方法 参数名和值 为sp el变量
		context.setVariable(methodParam.getParameterName(), args[i]);
	}
	return context;
}
 

public EvaluationContext createEvaluationContext(Limiter limiter, Method method, Object[] args, Object target, Class<?> targetClass, Method targetMethod,
                                                 Map<String, Object> injectArgs, BeanFactory beanFactory) {

    LimiterExpressionRootObject rootObject = new LimiterExpressionRootObject(limiter, method, args, target, targetClass);
    MethodBasedEvaluationContext evaluationContext = new MethodBasedEvaluationContext(rootObject, targetMethod, args, this.parameterNameDiscoverer);
    for (String key : injectArgs.keySet()) {
        evaluationContext.setVariable(key, injectArgs.get(key));
    }

    if (beanFactory != null) {
        evaluationContext.setBeanResolver(new BeanFactoryResolver(beanFactory));
    }
    return evaluationContext;
}
 

private EvaluationContext createEvaluationContext(PageContext pageContext) {
	StandardEvaluationContext context = new StandardEvaluationContext();
	context.addPropertyAccessor(new JspPropertyAccessor(pageContext));
	context.addPropertyAccessor(new MapAccessor());
	context.addPropertyAccessor(new EnvironmentAccessor());
	context.setBeanResolver(new BeanFactoryResolver(getRequestContext().getWebApplicationContext()));
	ConversionService conversionService = getConversionService(pageContext);
	if (conversionService != null) {
		context.setTypeConverter(new StandardTypeConverter(conversionService));
	}
	return context;
}
 

/**
 * Specify if the condition defined by the specified expression matches.
 */
public boolean condition(String conditionExpression, ApplicationEvent event, Method targetMethod,
		AnnotatedElementKey methodKey, Object[] args, @Nullable BeanFactory beanFactory) {

	EventExpressionRootObject root = new EventExpressionRootObject(event, args);
	MethodBasedEvaluationContext evaluationContext = new MethodBasedEvaluationContext(
			root, targetMethod, args, getParameterNameDiscoverer());
	if (beanFactory != null) {
		evaluationContext.setBeanResolver(new BeanFactoryResolver(beanFactory));
	}

	return (Boolean.TRUE.equals(getExpression(this.conditionCache, methodKey, conditionExpression).getValue(
			evaluationContext, Boolean.class)));
}
 

/**
 * 设置 request/response 参数的上下文
 *
 * @param secureExpressionHandler 上下文处理器
 * @param request                 请求
 * @param response                响应
 * @return 上下文
 */
public static StandardEvaluationContext getEvaluationContext(SecureExpressionHandler secureExpressionHandler, HttpServletRequest request, HttpServletResponse response) {
	// 初始化Sp el表达式上下文，并设置 处理函数
	StandardEvaluationContext context = new StandardEvaluationContext(secureExpressionHandler);
	// 设置表达式支持spring bean
	context.setBeanResolver(new BeanFactoryResolver(SpringUtil.getContext()));
	context.setVariable(SecureConstants.REQUEST, request);
	context.setVariable(SecureConstants.RESPONSE, response);
	return context;
}
 

/**
 * 包含方法上的参数的上下文
 *
 * @param secureExpressionHandler 上下文处理器
 * @param method                  方法
 * @param args                    参数
 * @return 上下文
 */
public static StandardEvaluationContext getEvaluationContext(SecureExpressionHandler secureExpressionHandler, Method method, Object[] args) {
	// 初始化Spel表达式上下文，并设置 处理函数
	StandardEvaluationContext context = new StandardEvaluationContext(secureExpressionHandler);
	// 设置表达式支持spring bean
	context.setBeanResolver(new BeanFactoryResolver(SpringUtil.getContext()));
	for (int i = 0; i < args.length; i++) {
		// 读取方法参数
		MethodParameter methodParam = ClassUtil.getMethodParameter(method, i);
		// 设置方法 参数名和值 为sp el变量
		context.setVariable(methodParam.getParameterName(), args[i]);
	}
	return context;
}