reactor-spring-core/src/main/java/reactor/spring/selector/ExpressionSelector.java
public static Selector expressionSelector(String expr, EvaluationContext evalCtx) {
        return new ExpressionSelector(SPEL_PARSER.parseExpression(expr), evalCtx);
    }
public static Selector expressionSelector(String expr, EvaluationContext evalCtx) {
        return new ExpressionSelector(SPEL_PARSER.parseExpression(expr), evalCtx);
    }
Helper method for creating an {@code ExpressionSelector}.

@param expr
The expression to parse.
@param evalCtx
The {@link org.springframework.expression.EvaluationContext} to use.

@return A new {@link reactor.bus.selector.Selector}