D-Net

package eu.dnetlib.pace.common;

import java.text.Normalizer;

import java.util.Collection;

import java.util.List;

import java.util.Set;

import java.util.StringTokenizer;

import org.apache.commons.io.IOUtils;

import org.apache.commons.lang.StringUtils;

import com.google.common.base.Joiner;

import com.google.common.collect.Iterables;

import com.google.common.collect.Lists;

import com.google.common.collect.Sets;

import eu.dnetlib.pace.clustering.NGramUtils;

import eu.dnetlib.pace.model.Field;

import eu.dnetlib.pace.model.FieldList;

import eu.dnetlib.pace.model.FieldListImpl;

/**

 * Set of common functions

 *

 * @author claudio

 *

 */

public abstract class AbstractPaceFunctions {

	protected static Set<String> stopwords = loadFromClasspath("/eu/dnetlib/pace/config/stopwords_en.txt");

	protected static Set<String> ngramBlacklist = loadFromClasspath("/eu/dnetlib/pace/config/ngram_blacklist.txt");

	private static final String alpha = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789 ";

	private static final String aliases_from = "⁰¹²³⁴⁵⁶⁷⁸⁹⁺⁻⁼⁽⁾ⁿ₀₁₂₃₄₅₆₇₈₉₊₋₌₍₎";

	private static final String aliases_to = "0123456789+-=()n0123456789+-=()";

	protected final static FieldList EMPTY_FIELD = new FieldListImpl();

	protected String concat(final List<String> l) {

		return Joiner.on(" ").skipNulls().join(l);

	}

	protected String cleanup(final String s) {

		final String s1 = nfd(s);

		final String s2 = fixAliases(s1);

		final String s3 = s2.replaceAll("–", " ");

		final String s4 = s3.replaceAll("&", " ");

		final String s5 = s4.replaceAll("−", " ");

		final String s6 = s5.replaceAll("([0-9]+)", " $1 ");

		final String s7 = s6.replaceAll("[^\\p{ASCII}]|\\p{Punct}", " ");

		final String s8 = s7.replaceAll("\\n", " ");

		final String s9 = s8.replaceAll("(?m)\\s+", " ");

		final String s10 = s9.trim();

		return s10;

	}

	protected String finalCleanup(final String s) {

		return s.toLowerCase();

	}

	protected boolean checkNumbers(final String a, final String b) {

		final String numbersA = getNumbers(a);

		final String numbersB = getNumbers(b);

		final String romansA = getRomans(a);

		final String romansB = getRomans(b);

		return !numbersA.equals(numbersB) || !romansA.equals(romansB);

	}

	protected String getRomans(final String s) {

		final StringBuilder sb = new StringBuilder();

		for (final String t : s.split(" ")) {

			sb.append(isRoman(t) ? t : "");

		}

		return sb.toString();

	}

	protected boolean isRoman(final String s) {

		return s.replaceAll("^M{0,4}(CM|CD|D?C{0,3})(XC|XL|L?X{0,3})(IX|IV|V?I{0,3})$", "qwertyuiop").equals("qwertyuiop");

	}

	protected String getNumbers(final String s) {

		return s.replaceAll("\\D", "");

	}

	protected String fixAliases(final String s) {

		final StringBuilder sb = new StringBuilder();

		for (final char ch : Lists.charactersOf(s)) {

			final int i = StringUtils.indexOf(aliases_from, ch);

			sb.append(i >= 0 ? aliases_to.charAt(i) : ch);

		}

		return sb.toString();

	}

	protected String removeSymbols(final String s) {

		final StringBuilder sb = new StringBuilder();

		for (final char ch : Lists.charactersOf(s)) {

			sb.append(StringUtils.contains(alpha, ch) ? ch : " ");

		}

		return sb.toString().replaceAll("\\s+", " ");

	}

	protected String getFirstValue(final Field values) {

		return (values != null) && !Iterables.isEmpty(values) ? Iterables.getFirst(values, EMPTY_FIELD).stringValue() : null;

	}

	protected boolean notNull(final String s) {

		return s != null;

	}

	// ///////////////////////

	protected String normalize(final String s) {

		return nfd(s).toLowerCase().replaceAll("(\\W|\\p{InCombiningDiacriticalMarks}|\\p{Punct}|\\d|\\n)+", " ").trim();

	}

	private String nfd(final String s) {

		return Normalizer.normalize(s, Normalizer.Form.NFD);

	}

	protected String filterStopWords(final String s, final Set<String> stopwords) {

		final StringTokenizer st = new StringTokenizer(s);

		final StringBuilder sb = new StringBuilder();

		while (st.hasMoreTokens()) {

			final String token = st.nextToken();

			if (!stopwords.contains(token)) {

				sb.append(token);

				sb.append(" ");

			}

		}

		return sb.toString().trim();

	}

	protected Collection<String> filterBlacklisted(final Collection<String> set, final Set<String> ngramBlacklist) {

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

		for (final String s : set) {

			if (!ngramBlacklist.contains(s)) {

				newset.add(s);

			}

		}

		return newset;

	}

	// ////////////////////

	public static Set<String> loadFromClasspath(final String classpath) {

		final Set<String> h = Sets.newHashSet();

		try {

			for (final String s : IOUtils.readLines(NGramUtils.class.getResourceAsStream(classpath))) {

				h.add(s);

			}

		} catch (final Throwable e) {

			return Sets.newHashSet();

		}

		return h;

	}

}