Utilities.java

/*
 *  Copyright (c) 2012 Daniel Huckaby
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package com.handlerexploit.prime.example.utils;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.List;

import org.codehaus.jackson.JsonFactory;
import org.codehaus.jackson.JsonParser;
import org.codehaus.jackson.JsonToken;

import android.content.Context;
import android.content.SharedPreferences;
import android.preference.PreferenceManager;

public class Utilities {
    
    private static final String PANORAMIO_URL = "http://www.panoramio.com/map/get_panoramas.php?order=popularity&set=public&from=0&to=%s&size=%s";
    
    public static List<Image> getPanoramioImages(Context context, int count, Size size) {
        return getRandomImages(context, String.format(PANORAMIO_URL, count, size.name().toLowerCase()));
    }
    
    public static enum Size {
        ORIGINAL,
        MEDIUM,
        SMALL,
        THUMBNAIL,
        SQUARE,
        MINI_SQUARE;
    }
    
    public static List<Image> getRandomThumbnailImages(Context context) {
        return getPanoramioImages(context, 500, Size.THUMBNAIL);
    }
    
    public static List<Image> getRandomLargeImages(Context context) {
        return getPanoramioImages(context, 500, Size.MEDIUM);
    }
    
    private static List<Image> getRandomImages(Context context, String source) {
        List<Image> images = new ArrayList<Image>();
        
        try {
            SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(context);
            String jsonTag = URLEncoder.encode(source);
            
            String rawJsonStringStream = sharedPreferences.getString(jsonTag, null);
            if (rawJsonStringStream == null) {
                rawJsonStringStream = toString(new URL(source).openStream());
                sharedPreferences.edit().putString(jsonTag, rawJsonStringStream).commit();
            }

            JsonFactory jsonFactory = new JsonFactory();
            JsonParser jsonParser = jsonFactory.createJsonParser(rawJsonStringStream);

            JsonToken current;

            current = jsonParser.nextToken();
            if (current != JsonToken.START_OBJECT) {
                return images;
            }

            while (jsonParser.nextToken() != JsonToken.END_OBJECT) {
                String fieldName = jsonParser.getCurrentName();
                current = jsonParser.nextToken();
                if ("photos".equals(fieldName)) {
                    if (current == JsonToken.START_ARRAY) {
                        while (jsonParser.nextToken() != JsonToken.END_ARRAY) {
                            fieldName = jsonParser.getCurrentName();
                            jsonParser.nextToken();
                            
                            Image image = new Image();
                            while (jsonParser.nextToken() != JsonToken.END_OBJECT) {
                                fieldName = jsonParser.getCurrentName();
                                if ("photo_title".equals(fieldName)) {
                                    image.title = jsonParser.getText();
                                } else if ("photo_file_url".equals(fieldName)) {
                                    image.imageURL = jsonParser.getText();
                                }
                            }
                            images.add(image);
                        }
                    } else {
                        jsonParser.skipChildren();
                    }
                } else {
                    jsonParser.skipChildren();
                }
            }
            jsonParser.close();
            
            if (images.size() == 0) {
                sharedPreferences.edit().putString(jsonTag, null).commit();
            }
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        
        return images;
    }
    
    private static String toString(InputStream input) throws IOException {
        final char[] buffer = new char[0x10000];
        StringBuilder stringBuilder = new StringBuilder();
        Reader reader = new InputStreamReader(input, "UTF-8");
        int i;
        do {
            i = reader.read(buffer, 0, buffer.length);
            if (i > 0) {
                stringBuilder.append(buffer, 0, i);
            }
        } while (i >= 0);
        return stringBuilder.toString();
    }
    
    public static class Image {
        public String title;
        public String imageURL;
    }
}