n-gram implementaion in spring-boot ElasticSearch - elasticsearch

Question

I am trying to achieve autocomplete in elasticsearch, I am using it inside spring boot, I have tried a lot and tried with many example from internet but not able to make it. below is my code example pls help me on this.
Main Class:-
#SpringBootApplication
#EnableNatsAnnotations
#EnableAutoConfiguration
#EnableConfigurationProperties(ElasticsearchProperties.class)
#EntityScan(basePackages = {
"com.text.model"
})
#ComponentScan(
{
"com.text.elastic",
"com.text.elastic.controller",
"com.text.elastic.service",
"com.text.elastic.service.impl",
"com.text.nats.utils"
}
)
public class ElasticServicesApplication {
public static void main(String[] args) {
SpringApplication.run(ElasticServicesApplication.class, args);
}
}
Bean Class:-
#Setting(settingPath = "elasticsearch-settings.json")
#Document(indexName = "content", type = "content", shards = 1, replicas = 0, createIndex = true, refreshInterval = "-1")
public class Content {
#Id
private String id;
private Locale locale;
// #Field(type = text, index = true, store = true, analyzer = "standard")
#Field(
type = FieldType.String,
index = FieldIndex.analyzed,
searchAnalyzer = "standard",
//indexAnalyzer = "type_ahead",
analyzer = "standard"
/*,
store = true*/
)
private String contentTitle;
Here I want to achieve it in contentTitle.

Answer 1

Mapping
Concise way of using annotation:
#CompletionField()
private Completion suggest;
Or more powerful but tedious way:
{
"content" : {
"properties" : {
"contentTitle" : { "type" : "string" },
"suggest" : { "type" : "completion",
"analyzer" : "simple",
"search_analyzer" : "simple"
}
}
}
}
//Then refer to the mapping by `#Mapping`:
#Setting(settingPath = "elasticsearch-settings.json")
#Document(indexName = "content", type = "content", shards = 1, replicas = 0, createIndex = true, refreshInterval = "-1")
#Mapping(mappingPath = "/mappings/content-mapping.json")
public class Content {...}
Index
We can index as our common entity:
esTemplate.save(new File(...));
Query
The ElasticsearchTemplate has the method for query suggest:
public SuggestResponse suggest(SuggestBuilder.SuggestionBuilder<?> suggestion, String... indices);
Ref
Blog posts about completion
Official document about completion