src/main/java/de/ids_mannheim/korap/query/spans/NextSpans.java

package de.ids_mannheim.korap.query.spans;

import java.io.IOException;

import java.util.Map;

import org.apache.lucene.index.AtomicReaderContext;
import org.apache.lucene.index.Term;
import org.apache.lucene.index.TermContext;
import org.apache.lucene.util.Bits;


import de.ids_mannheim.korap.query.SimpleSpanQuery;

/**	NextSpans is an enumeration of Span matches, which ensures that  
 * 	a span is immediately followed by another span.
 *  
 * 	TODO: nextSpans needs collectPayloads to be explicitly set true. Why?
 *            ndiewald: They don't have to be set explicitely - just make them use it always
 * 	@author margaretha 
 * */
public class NextSpans extends NonPartialOverlappingSpans {	
	
    public NextSpans (SimpleSpanQuery simpleSpanQuery,
		      AtomicReaderContext context,
		      Bits acceptDocs,
		      Map<Term,TermContext> termContexts) throws IOException {
    	super(simpleSpanQuery, context, acceptDocs, termContexts);    	
    };

    /** Check weather the end position of the current firstspan equals 
     *  the start position of the secondspan. 
     **/
    @Override
    protected int findMatch() {		
	if (firstSpans.end() == secondSpans.start()) {			
	    matchDocNumber = firstSpans.doc();
	    matchStartPosition = firstSpans.start();
	    matchEndPosition = secondSpans.end();	
	    return 0;
	}		
	else if (firstSpans.end() > secondSpans.start())
	    return 1;
	
	return -1;		
    };	
};