public SpringELExpressionParser getSpringExpressionParser() {
        val configuration = new SpelParserConfiguration();
        val spelExpressionParser = new SpelExpressionParser(configuration);
        val parser = new SpringELExpressionParser(spelExpressionParser, this.flowBuilderServices.getConversionService());
        parser.addPropertyAccessor(new ActionPropertyAccessor());
        parser.addPropertyAccessor(new BeanExpressionContextAccessor());
        parser.addPropertyAccessor(new BeanFactoryPropertyAccessor());
        parser.addPropertyAccessor(new FlowVariablePropertyAccessor());
        parser.addPropertyAccessor(new MapAdaptablePropertyAccessor());
        parser.addPropertyAccessor(new MessageSourcePropertyAccessor());
        parser.addPropertyAccessor(new ScopeSearchingPropertyAccessor());
        parser.addPropertyAccessor(new MapAccessor());
        parser.addPropertyAccessor(new MapAdaptablePropertyAccessor());
        parser.addPropertyAccessor(new EnvironmentAccessor());
        parser.addPropertyAccessor(new ReflectivePropertyAccessor());
        return parser;
    }
Gets spring expression parser.

@return the spring expression parser
core/cas-server-core-webflow-api/src/main/java/org/apereo/cas/web/flow/configurer/AbstractCasWebflowConfigurer.java