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package eu.dnetlib.pace.clustering;
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import java.util.Collection;
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import java.util.Map;
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import java.util.Set;
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import com.google.common.collect.Sets;
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/**
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* The Class SuffixPrefix.
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*/
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public class SuffixPrefix extends AbstractClusteringFunction {
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/**
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* Instantiates a new suffix prefix.
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*
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* @param params
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* the params
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*/
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public SuffixPrefix(final Map<String, Integer> params) {
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super(params);
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}
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/*
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* (non-Javadoc)
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*
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* @see eu.dnetlib.pace.clustering.AbstractClusteringFunction#doApply(java.lang.String)
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*/
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@Override
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protected Collection<String> doApply(final String s) {
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return suffixPrefix(s, param("len"), param("max"));
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}
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/**
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* Suffix prefix.
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*
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* @param s
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* the s
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* @param len
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* the len
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* @param max
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* the max
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* @return the collection
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*/
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private Collection<String> suffixPrefix(final String s, final int len, final int max) {
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final Set<String> bigrams = Sets.newLinkedHashSet();
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int i = 0;
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while ((++i < s.length()) && (bigrams.size() < max)) {
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int j = s.indexOf(" ", i);
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int offset = (j + len + 1) < s.length() ? j + len + 1 : s.length();
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if ((j - len) > 0) {
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String bigram = s.substring(j - len, offset).replaceAll(" ", "").trim();
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if (bigram.length() >= 4) {
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bigrams.add(bigram);
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}
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}
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}
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return bigrams;
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}
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}
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