How to implement the custom converter for a field using Spring Data Elasticsearch?

Question

I need to implement a custom converter in spring data elastic-search. I need to concatenate something to the text when saving and retrieving. I have seen a similar question is here. And in the answer is says it is implemented now and available. But I didn't found any example how to implement it. So anybody know how to do this?

Answer 1

You can find examples in the test code of the library.

You have to create a converter:

class FooConverter implements PropertyValueConverter {

    public static final String PREFIX = "foo-";

    @Override
    public Object write(Object value) {
        return PREFIX + value.toString();
    }

    @Override
    public Object read(Object value) {

        String valueString = value.toString();

        if (valueString.startsWith(PREFIX)) {
            return valueString.substring(PREFIX.length());
        } else {
            return value;
        }
    }
}

and then register it for the property of your entity class:

@Document(indexName = "foo")
class Entity {
    
    @Field(type = FieldType.Text)
    @ValueConverter(FooConverter.class)
    private String someField;
    
    // ...
}