在Camel Spring-Boot微服务中实现静态缓存？

Question

I have a Spring-boot/Camel microservice that accepts XML via a Restful POST with various header parms (1), transforms the XML via a static xQuery file stored on the classpath (2), then based on vales of the result retrieve a set of XSL templates from a relational database using SQL(3). These templates are themselves then transformed and assembled using xQuery (4), then the original Transformed XML from the POST method is transformed using the transformed/assembled XSL template (5) before being sent off to an external service (6).

This all sort of works right now by storing the body of various steps as exchange properties, including the static XSL templates from the database using a processor. The exchange properties are accessible from my xQuery so all is good. At various steps I also replace the body with values temporarily stored as exchanged properties. This all seems clumsy to me...

My real question is what is the best way to cache all the XSL templates during application startup so that subsequent calls to the DB are unnecessary? They are static and less than 10 in number. I was just thinking of storing them in a classic singleton from a processor in a route that executes at startup, then accessing them using the processor used in step 3 to set exchange variables to the templates I need. Is there a better way of doing this?

Answer 1

I opted to make a Spring bean to hold my XSL Templates and then do this in my RouteBuilder class so it would cache the templates upon startup and make them accessible to other routes:

@Autowired
XSLTemplates xslTemplates;

@Override
public void configure() throws Exception {
    // get the templates from the database upon app startup and store
    from("timer://mytimer?repeatCount=1")
        .to("sql:select ID, XSL_TEMPLATE from table").split()
        .simple("${body}")
        .process(new Processor() {
            public void process(Exchange exchange) throws Exception {
                Map<String, Object> row = exchange.getIn().getBody(Map.class);
                if (row.get("ID").toString().equals("fooTemplate")) {
                    xslTemplates.setFooTemplate(row.get("XSL_TEMPLATE).toString());
                }  else... everything else

            }
        });