WikidataInterface.java

package com.formulasearchengine.mathosphere.mlp.text;

import net.sf.json.JSONArray;
import net.sf.json.JSONException;
import net.sf.json.JSONObject;
import net.sf.json.JSONSerializer;

import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.utils.URIBuilder;
import org.apache.http.impl.client.DefaultHttpClient;
import org.xml.sax.SAXException;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.xpath.XPathExpressionException;

/**
 * Created by Moritz on 28.09.2015.
 */
public class WikidataInterface {
  private static String makeRequest(String term, String lang) throws URISyntaxException, IOException {
    HttpClient client = new DefaultHttpClient();
    URI uri = new URIBuilder()
      .setScheme("http")
      .setHost("www.wikidata.org")
      .setPath("/w/api.php")
      .setParameter("format", "json")
      .setParameter("action", "wbsearchentities")
      .setParameter("uselang", "en")
      .setParameter("language", lang)
      .setParameter("search", term)
      .build();
    HttpGet get = new HttpGet(uri);
    HttpResponse response = client.execute(get);
    BufferedReader rd = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
    String line;
    String result = "";
    while ((line = rd.readLine()) != null) {
      result += line;
    }
    return result;
  }

  private static String getAlias(String qid, String lang) throws URISyntaxException, IOException {
    HttpClient client = new DefaultHttpClient();
    URI uri = new URIBuilder()
      .setScheme("http")
      .setHost("www.wikidata.org")
      .setPath("/w/api.php")
      .setParameter("format", "json")
      .setParameter("action", "wbgetentities")
      .setParameter("languages", "en")
      .setParameter("ids", qid)
      .setParameter("props", "aliases")
      .build();
    HttpGet get = new HttpGet(uri);
    HttpResponse response = client.execute(get);
    BufferedReader rd = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
    String line;
    String result = "";
    while ((line = rd.readLine()) != null) {
      result += line;
    }
    return result;
  }

  public static List<String> getEntities(String text) throws XPathExpressionException, ParserConfigurationException, SAXException, IOException, TransformerException, URISyntaxException {
    final ArrayList<String> strings = new ArrayList<>();
    long t1 = System.nanoTime();
    String json = makeRequest(text, "en");
    System.out.println((System.nanoTime() - t1) / 1000000);
    try {
      JSONObject Ojson = (JSONObject) JSONSerializer.toJSON(json);
      if (Ojson.getInt("success") < 1) {
        return strings;
      }
      JSONArray results = Ojson.getJSONArray("search");
      for (Object result : results) {
        final JSONObject sres = (JSONObject) result;
        strings.add(sres.getString("id"));
      }
    } catch (Exception e) {
      e.printStackTrace();
    }
    return strings;
  }

  public static List<String> getAliases(String qid) throws XPathExpressionException, ParserConfigurationException, SAXException, IOException, TransformerException, URISyntaxException {
    final ArrayList<String> strings = new ArrayList<>();
    long t1 = System.nanoTime();
    String json = getAlias(qid, "en");
    System.out.println((System.nanoTime() - t1) / 1000000);
    try {
      JSONObject Ojson = (JSONObject) JSONSerializer.toJSON(json);
      if (Ojson.getInt("success") < 1) {
        return Arrays.asList(new String[]{"fail!"});
      }
      try {
        JSONArray results = ((JSONObject) ((JSONObject) ((JSONObject) Ojson.get("entities")).get(qid)).get("aliases")).getJSONArray("en");
        for (Object result : results) {
          final JSONObject sres = (JSONObject) result;
          strings.add((String) sres.get("value"));
        }
      } catch (JSONException e) {
        System.out.println(((JSONObject) ((JSONObject) ((JSONObject) Ojson.get("entities")).get(qid)).get("aliases")));
      }
    } catch (Exception e) {
      e.printStackTrace();
    }
    return strings;
  }
}