Bibstem Transformer

BibstemTransformer

package org.apache.solr.handler.dataimport;

import java.util.List;
import java.util.Map;
import java.util.regex.Pattern;

public class BibstemTransformer extends Transformer {

    private static Pattern fourDigit = Pattern.compile("^\\d{4}.+"); 
    private static Pattern lastFour = Pattern.compile("^[\\.\\d]+$");
    
	public static boolean hasVolume(String bibcode) {
		return lastFour.matcher(bibcode.substring(9, 13)).matches();
	}
	
	public static String extractBibstem(String bibcode) {
		if (hasVolume(bibcode)) {
			return bibcode.substring(4, 9).replace(".", "");
		} else {
			return bibcode.substring(4, 13);
		}
	}
	
	@Override
	public Object transformRow(Map<String, Object> row, Context context) {
		String bibcode = (String) row.get("bibcode");
		String[] bibstems = new String[2];
		bibstems[0] = bibcode.substring(4,9).replace(".", "");
		bibstems[1] = trimDots(bibcode.substring(4,13));
		row.put("bibstem_facet", extractBibstem(bibcode));
		row.put("bibstem", bibstems);
		return row;
	}

	private String trimDots(String value) {
		int s = 0;
		int e = value.length()-1;
		while(e>s) {
			if (value.charAt(e) == '.') {
				e--;
			}
			else {
				break;
			}
		}
		while(s<e) {
			if (value.charAt(s) == '.') {
				s++;
			}
			else {
				break;
			}
		}
		return value.substring(s, e+1);
	}
}