[CAMEL-11970] JacksonDataFormat does not pickup custom ObjectMapper from Registry

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.19.2, 2.19.3, 2.20.0
• Fix Version/s: 2.21.0
• Component/s: camel-jackson
• Estimated Complexity: Unknown
• Flags: Patch
• Assignee: Claus Ibsen
• Reporter: Tim Lark
• Created: 31/Oct/17 19:49
• Updated: 02/Nov/17 12:48
• Resolved: 02/Nov/17 12:48

Description

When a custom ObjectMapper is properly configured as a Spring bean and exists in the Registry, it is ignored when the JacksonDataFormat.doStart method is invoked.

The beginning of this method does a null check on objectMapper and simply creates one via new ObjectMapper() if null.

I've prototyped a more robust solution below, which does pickup our custom ObjectMapper bean:
Before:

    @Override
    protected void doStart() throws Exception {
        if (objectMapper == null) {
            objectMapper = new ObjectMapper();
        }
...

After:

    @Override
    protected void doStart() throws Exception {
        if (objectMapper == null) {
            CamelContext context = getCamelContext();
            if (context == null) {
                LOG.error("doStart: No camelContext defined");
            }
            else {
                Map<String, ObjectMapper> mappersByName = context
                        .getRegistry()
                        .findByTypeWithName(ObjectMapper.class);
                LOG.debug("doStart: Found objectMappers={}", mappersByName);
                if (mappersByName.size() >= 1) {
                    Map.Entry<String, ObjectMapper> mapperByName = mappersByName
                            .entrySet()
                            .iterator()
                            .next();
                    objectMapper = mapperByName.getValue();
                    LOG.debug("doStart: Using objectMapper=[name:{}, {}]", mapperByName.getKey(), objectMapper);
                }
            }
            if (objectMapper == null) {
                objectMapper = new ObjectMapper();
                LOG.warn("doStart: Using new default objectMapper={}", objectMapper);
            }
        }
...

An enhancement to this would be to allow the bean name to be specified instead of simply choosing the first one found.