D-Net

package eu.dnetlib.pace.clustering;

import java.util.Collection;

import java.util.Map;

import java.util.Set;

import com.google.common.collect.Sets;

public class SuffixPrefix extends AbstractClusteringFunction {

	public SuffixPrefix(Map<String, Integer> params) {

		super(params);

	}

	@Override

	protected Collection<String> doApply(String s) {

		return suffixPrefix(s, param("len"), param("max"));

	}

	private Collection<String> suffixPrefix(String s, int len, int max) {

		final Set<String> bigrams = Sets.newLinkedHashSet();

		int i = 0;

		while (++i < s.length() && bigrams.size() < max) {

			int j = s.indexOf(" ", i);

			int offset = j + len + 1 < s.length() ? j + len + 1 : s.length();

			if (j - len > 0) {

				String bigram = s.substring(j - len, offset).replaceAll(" ", "").trim();

				if (bigram.length() >= 4) {

					bigrams.add(bigram);

				}

			}

		}

		return bigrams;

	}

}