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Session: How to Use MoreLikeThis

MoreLikeThis is available through query methods and will return similar documents according to the provided criteria and options.

Syntax

IDocumentQuery<T> moreLikeThis(MoreLikeThisBase moreLikeThis);

IDocumentQuery<T> moreLikeThis(Consumer<IMoreLikeThisBuilderForDocumentQuery<T>> builder);

Parameters
moreLikeThis MoreLikeThisBase Defines the type of MoreLikeThis that should be executed
builder Consumer<IMoreLikeThisBuilderForDocumentQuery<T>> Builder with fluent API that constructs the MoreLikeThisBase instance

Builder

IMoreLikeThisOperations<T> usingAnyDocument();

IMoreLikeThisOperations<T> usingDocument(String documentJson);

IMoreLikeThisOperations<T> usingDocument(Consumer<IFilterDocumentQueryBase<T, IDocumentQuery<T>>> builder);

IMoreLikeThisOperations<T> withOptions(MoreLikeThisOptions options);

Parameters
documentJson String Inline JSON document that will be used as a base for operation
builder Consumer<IFilterDocumentQueryBase<T, IDocumentQuery<T>>> Filtering expression utilized to find a document that will be used as a base for operation
options MoreLikeThisOptions Non-default options that should be used for operation

Options

private Integer minimumTermFrequency = 2;
private Integer maximumQueryTerms = 25;
private Integer maximumNumberOfTokensParsed = 5000;
private Integer minimumWordLength = 0;
private Integer maximumWordLength = 0;
private Integer minimumDocumentFrequency = 5;
private Integer maximumDocumentFrequency = Integer.MAX_VALUE;
private Integer maximumDocumentFrequencyPercentage;
private Boolean boost = false;
private Float boostFactor = 1f;
private String stopWordsDocumentId;
private String[] fields;

// getters and setters

Options
MinimumTermFrequency Integer Ignores terms with less than this frequency in the source doc
MaximumQueryTerms Integer Returns a query with no more than this many terms
MaximumNumberOfTokensParsed Integer The maximum number of tokens to parse in each example doc field that is not stored with TermVector support
MinimumWordLength Integer Ignores words less than this length or, if 0, then this has no effect
MaximumWordLength Integer Ignores words greater than this length or if 0 then this has no effect
MinimumDocumentFrequency Integer Ignores words which do not occur in at least this many documents
MaximumDocumentFrequency Integer Ignores words which occur in more than this many documents
MaximumDocumentFrequencyPercentage Integer Ignores words which occur in more than this percentage of documents
Boost Boolean Boost terms in query based on score
BoostFactor Float Boost factor when boosting based on score
StopWordsDocumentId String Document ID containing custom stop words
Fields String[] Fields to compare

Example I

// Search for similar articles to 'articles/1'
// using 'Articles/MoreLikeThis' index and search only field 'body'
MoreLikeThisOptions options = new MoreLikeThisOptions();
options.setFields(new String[]{ "body" });

List<Article> articles = session
    .query(Article.class, Query.index("Articles/MoreLikeThis"))
    .moreLikeThis(builder -> builder
        .usingDocument(x -> x.whereEquals("id()", "articles/1"))
        .withOptions(options))
    .toList();
from index 'Articles/MoreLikeThis' 
where morelikethis(id() = 'articles/1', '{ "Fields" : [ "body" ] }')

Example II

// Search for similar articles to 'articles/1'
// using 'Articles/MoreLikeThis' index and search only field 'body'
// where article category is 'IT'
MoreLikeThisOptions options = new MoreLikeThisOptions();
options.setFields(new String[]{ "body" });
List<Article> articles = session
    .query(Article.class, Query.index("Articles/MoreLikeThis"))
    .moreLikeThis(builder -> builder
        .usingDocument(x -> x.whereEquals("id()", "articles/1"))
        .withOptions(options))
    .whereEquals("category", "IT")
    .toList();
from index 'Articles/MoreLikeThis' 
where morelikethis(id() = 'articles/1', '{ "Fields" : [ "body" ] }') and category == 'IT'