Reworked version of data fetching code

BaseDataFetch.java

package pl.kobietydokodu.wyzwanie;

import java.io.IOException;
import java.io.InputStream;
import java.net.URI;

import org.apache.http.HttpEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public abstract class BaseDataFetch <T, RT> {

    private CloseableHttpClient httpclient = HttpClients.createDefault();
    protected Logger log = LoggerFactory.getLogger(getClass());
    
    public final RT readRemoteData() {
        
        HttpGet httpGet = new HttpGet(buildRequestURI());
        CloseableHttpResponse response = null;
        try {
            response = httpclient.execute(httpGet);
            log.debug("Received response: {}", response.getStatusLine());
            HttpEntity entity = response.getEntity();

            RT rawObject = readRawData(entity.getContent());

            EntityUtils.consume(entity);
            return rawObject;
        } catch (IOException e) {
            handleError(e);
        } finally {
            try {
                response.close();
            } catch (IOException e) {
                log.warn("Cannot close stream", e);
            }
        }
        throw new IllegalStateException("Fetching remote stream failed, cannot recover");
    }
    
    protected void handleError(Exception e) {
        log.error("Unknown error during the process", e);
    }

    protected abstract URI buildRequestURI();
    
    protected abstract RT readRawData(InputStream stream);
    
    protected abstract T convert(RT intermediateType);
    
    public T fetch() {
        RT rawDataObject = readRemoteData();
        T finalObject = convert(rawDataObject);
        return finalObject;
    }
    
}

BaseJSONDataFetch.java

package pl.kobietydokodu.wyzwanie;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;

import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;
import org.json.simple.parser.ParseException;

public abstract class BaseJSONDataFetch <T> extends BaseDataFetch<T, JSONObject> {

    @Override
    protected JSONObject readRawData(InputStream stream) {
        JSONParser parser = new JSONParser();
        try {
            Object obj = parser.parse(new InputStreamReader(stream));
            return (JSONObject) obj;
        } catch (IOException e) {
            handleError(e);
        } catch (ParseException e) {
            handleError(e);
        }
        throw new IllegalStateException("Cannot convert input stream to intermediate object");
    }
    
}

FetchWeather.java

package pl.kobietydokodu.wyzwanie;

import java.net.URI;
import java.net.URISyntaxException;

import org.apache.http.client.utils.URIBuilder;
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;

public class FetchWeather extends BaseJSONDataFetch<TimestampWithDescription> {

    @Override
    protected URI buildRequestURI() {
        try {
            URIBuilder requestUri = new URIBuilder("https://query.yahooapis.com/v1/public/yql");
            requestUri.addParameter("format", "json");
            requestUri.addParameter("q", "select * from weather.forecast where woeid in (select woeid from geo.places(1) where text=\"wrocław\")");
            return requestUri.build();
        } catch (URISyntaxException e) {
            handleError(e);
            throw new IllegalStateException("Cannot build URI", e);
        }
    }

    @Override
    protected TimestampWithDescription convert(JSONObject intermediateType) {
        JSONObject queryObject = (JSONObject) intermediateType.get("query");
        JSONObject resultsObject = (JSONObject) queryObject.get("results");
        JSONObject channelObject = (JSONObject) resultsObject.get("channel");
        JSONObject itemObject = (JSONObject) channelObject.get("item");
        JSONArray forecastArray = (JSONArray) itemObject.get("forecast");
        JSONObject forecastObject = (JSONObject) forecastArray.get(0);
        
        String description = (String) forecastObject.get("text");
        String date = (String) forecastObject.get("date");
        
        return new TimestampWithDescription(date, description);
    }
    
}

FetchWikipedia.java

package pl.kobietydokodu.wyzwanie;

import java.net.URI;
import java.net.URISyntaxException;

import org.apache.http.client.utils.URIBuilder;
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;

public class FetchWikipedia extends BaseJSONDataFetch<TimestampWithDescription> {

    @Override
    protected URI buildRequestURI() {
        try {
            URIBuilder requestUri = new URIBuilder("https://en.wikipedia.org/w/api.php");
            requestUri.addParameter("action", "query");
            requestUri.addParameter("format", "json");
            requestUri.addParameter("prop", "revisions");
            requestUri.addParameter("titles", "Main Page");
            return requestUri.build();
        } catch (URISyntaxException e) {
            handleError(e);
            throw new IllegalStateException("Cannot build URI", e);
        }
    }

    @Override
    protected TimestampWithDescription convert(JSONObject intermediateType) {
        JSONObject queryObject = (JSONObject) intermediateType.get("query");
        JSONObject pagesObject = (JSONObject) queryObject.get("pages");
        Object key = pagesObject.keySet().iterator().next();
        JSONObject pageObject = (JSONObject) pagesObject.get(key);
        JSONArray revisionsArray = (JSONArray) pageObject.get("revisions");
        JSONObject revisionObject = (JSONObject) revisionsArray.get(0);

        String description = (String) revisionObject.get("comment");
        String date = (String) revisionObject.get("timestamp");
        
        return new TimestampWithDescription(date, description);
    }
}