Gson parsing sample code

MovieRestTest.java

package ms;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.lang.reflect.Type;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonArray;
import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParseException;
import com.google.gson.JsonParser;

public class Solution {

    final static Gson gson = new GsonBuilder().setPrettyPrinting().setLenient().registerTypeAdapter(ServerResponse.class, new ServerResponse.Deserializer()).create();

    public static String[] getMovieTitles(String substr) throws IOException {
        List<String> results = new ArrayList<>();
        int pageCount = getPageCount(substr);

        if (pageCount == 0) {
            return new String[0];
        }

        for (int i = 1; i <= pageCount; i++) {
            results.addAll(getData(substr, i));
        }

        // sort the list once the list has all the results added so we only sort once.
        Collections.sort(results, new Comparator<String>() {
            @Override
            public int compare(String o1, String o2) {
                return o1.compareTo(o2);
            }
        });

        return results.toArray(new String[results.size()]);
    }

    /**
     * This returns list of movie titles queried by the substr and the page number.
     *
     * @param substr
     * @param pageCount
     * @return
     * @throws IOException
     */
    static List<String> getData(String substr, int pageNumber) throws IOException {
        String serverReply = makeServerCall(substr, pageNumber);

        ServerResponse response = gson.fromJson(serverReply, ServerResponse.class);
        List<String> results = new ArrayList<>();
        for (MovieInfo movie : response.getData()) {
            results.add(movie.title);
        }
        return results;
    }

    static int getPageCount(String substr) throws IOException {

        String serverReply = makeServerCall(substr, 0);
        ServerResponse response = gson.fromJson(serverReply, ServerResponse.class);
        return response.totalPages;
    }

    /*
     * The heart of this class, makes the server call and retrieves json string as server reply.
     */
    static String makeServerCall(String substr, int pageNo) throws IOException{

        URL url;
        if(pageNo>=1) {
            url= new URL("https://jsonmock.hackerrank.com/api/movies/search/?Title=" + substr + "&page="+pageNo);
        }else{
            url= new URL("https://jsonmock.hackerrank.com/api/movies/search/?Title=" + substr);
        }
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        conn.setRequestMethod("GET");
        conn.setRequestProperty("Accept", "application/json");

        if (conn.getResponseCode() != 200) {
            throw new RuntimeException("Failed : HTTP error code : " + conn.getResponseCode());
        }

        BufferedReader br = new BufferedReader(new InputStreamReader((conn.getInputStream())));
        String temp;
        StringBuffer output = new StringBuffer();

        while ((temp = br.readLine()) !=null ) {
            output.append(temp);
        }

        return output.toString();
    }

    static class MovieInfo {
        private String posterUrl;
        private String title;
        private int year;
        private String type;
        private String imdbId;

        public MovieInfo(String posterUrl, String title, int year, String type, String imdbId) {
            this.posterUrl = posterUrl;
            this.title = title;
            this.year = year;
            this.type = type;
            this.imdbId = imdbId;
        }

        public String getPosterUrl() {
            return posterUrl;
        }

        public void setPosterUrl(String posterUrl) {
            this.posterUrl = posterUrl;
        }

        public String getTitle() {
            return title;
        }

        public void setTitle(String title) {
            this.title = title;
        }

        public int getYear() {
            return year;
        }

        public void setYear(int year) {
            this.year = year;
        }

        public String getType() {
            return type;
        }

        public void setType(String type) {
            this.type = type;
        }

        public String getImdbId() {
            return imdbId;
        }

        public void setImdbId(String imdbId) {
            this.imdbId = imdbId;
        }

    }

    static class ServerResponse {

        private int page;
        private int perPage;
        private int total;
        private int totalPages;
        private List<MovieInfo> data;

        public ServerResponse(int page, int perPage, int total, int totalPages, List<MovieInfo> data) {

            this.page = page;
            this.perPage = perPage;
            this.total = total;
            this.totalPages = totalPages;
            this.data = data;
        }

        public int getPage() {
            return page;
        }

        public void setPage(int page) {
            this.page = page;
        }

        public int getPerPage() {
            return perPage;
        }

        public void setPerPage(int perPage) {
            this.perPage = perPage;
        }

        public int getTotal() {
            return total;
        }

        public void setTotal(int total) {
            this.total = total;
        }

        public int getTotalPages() {
            return totalPages;
        }

        public void setTotalPages(int totalPages) {
            this.totalPages = totalPages;
        }

        public List<MovieInfo> getData() {
            return data;
        }

        public void setData(List<MovieInfo> data) {
            this.data = data;
        }

        static final class Deserializer implements JsonDeserializer<ServerResponse> {

            /**
             * {@inheritDoc}
             */
            @Override
            public ServerResponse deserialize(final JsonElement json, final Type typeOfT,
                    final JsonDeserializationContext context) throws JsonParseException {
                final JsonObject jObject = json.getAsJsonObject();
                final int page = jObject.get("page").getAsInt();
                final int perPage = jObject.get("per_page").getAsInt();
                final int total = jObject.get("total").getAsInt();
                final int totalPages = jObject.get("total_pages").getAsInt();
                final JsonArray jsonArray = jObject.get("data").getAsJsonArray();
                final List<MovieInfo> movieList = new ArrayList<>();

                for (int i = 0; i < jsonArray.size(); i++) {
                    final JsonObject movieJson = jsonArray.get(i).getAsJsonObject();
                    final String imdbId = movieJson.get("imdbID").getAsString();
                    final String title = movieJson.get("Title").getAsString();
                    final int year = movieJson.get("Year").getAsInt();
                    final String posterUrl = movieJson.get("Poster").getAsString();
                    final String type = movieJson.get("Type").getAsString();

                    final MovieInfo MovieInfo = new MovieInfo(imdbId, title, year, posterUrl, type);
                    movieList.add(MovieInfo);
                }

                return new ServerResponse(page, perPage, total, totalPages, movieList);
            }

        }
    }

    public static void main(String[] args) {

        try {
            String[] sortedMovieTitles = getMovieTitles("spiderman");
            for(String str:sortedMovieTitles) {
                System.out.println(str);
            }
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }
}
//output
//Amazing Spiderman Syndrome
//Fighting, Flying and Driving: The Stunts of Spiderman 3
//Hollywood's Master Storytellers: Spiderman Live
//Italian Spiderman
//Spiderman
//Spiderman
//Spiderman 5
//Spiderman and Grandma
//Spiderman in Cannes
//Superman, Spiderman or Batman
//The Amazing Spiderman T4 Premiere Special
//The Death of Spiderman
//They Call Me Spiderman