Class DocumentValueSourceDictionary

Dictionary with terms and optionally payload information taken from stored fields in a Lucene index. Similar to DocumentDictionary, except it obtains the weight of the terms in a document based on a ValueSource.

• The term and (optionally) payload fields have to be stored
• if the term or (optionally) payload fields supplied do not have a value for a document, then the document is rejected by the dictionary

In practice the ValueSource will likely be obtained using the lucene expression module. The following example shows how to create a ValueSource from a simple addition of two fields:

  Expression expression = JavascriptCompiler.Compile("f1 + f2");
  SimpleBindings bindings = new SimpleBindings();
  bindings.Add(new SortField("f1", SortField.Type_e.LONG));
  bindings.Add(new SortField("f2", SortField.Type_e.LONG));
  ValueSource valueSource = expression.GetValueSource(bindings);