Wrapper to allow {@link SpanQuery} objects participate in composite single-field SpanQueries by 'lying' about their search field. That is, the masked SpanQuery will function as normal, but {@link SpanQuery#GetField()} simply hands back the value supplied in this class's constructor.

This can be used to support Queries like {@link SpanNearQuery} or {@link SpanOrQuery} across different fields, which is not ordinarily permitted.

This can be useful for denormalized relational data: for example, when indexing a document with conceptually many 'children':

            teacherid: 1
            studentfirstname: james
            studentsurname: jones
            
            teacherid: 2
            studenfirstname: james
            studentsurname: smith
            studentfirstname: sally
            studentsurname: jones
            

a SpanNearQuery with a slop of 0 can be applied across two {@link SpanTermQuery} objects as follows:

            SpanQuery q1  = new SpanTermQuery(new Term("studentfirstname", "james"));
            SpanQuery q2  = new SpanTermQuery(new Term("studentsurname", "jones"));
            SpanQuery q2m new FieldMaskingSpanQuery(q2, "studentfirstname");
            Query q = new SpanNearQuery(new SpanQuery[]{q1, q2m}, -1, false);
            

to search for 'studentfirstname:james studentsurname:jones' and find teacherid 1 without matching teacherid 2 (which has a 'james' in position 0 and 'jones' in position 1).

Note: as {@link #GetField()} returns the masked field, scoring will be done using the norms of the field name supplied. This may lead to unexpected scoring behaviour.

[SerializableAttribute]
public class FieldMaskingSpanQuery : SpanQuery

<SerializableAttribute> _
Public Class FieldMaskingSpanQuery _
	Inherits SpanQuery

[SerializableAttribute]
public ref class FieldMaskingSpanQuery : public SpanQuery