Get.java :  » Location » recycle-locator » com » net » finditnow » Android Open Source

/***
 * Get.java by Eric Hare
 * This class defines our Retrieve Locations interface with the PHP layer
 * It is called to retrieve items from the database, including categories and buildings
 */

package com.net.finditnow;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONTokener;

import android.util.Log;

import com.google.android.maps.GeoPoint;

public class Get {
  
  // A Constant representing the location of the root of the get files
  private static final String GET_LOCATIONS_ROOT = "http://yinnopiano.com/fin/";
  
  /**
   * This method processes a request to retrieve locations from the database
   * It is used for plotting the locations properly on the map
   * 
   * @param category The category of items to retrieve
   * @param item If the category is supplies, the type of supplies to retrieve
   * @param location The location of the user making the request
   * 
   * @return A JSONArray of locations, categories, or buildings from the database
   */
  public static JSONArray requestFromDB(String category, String item, GeoPoint location) {

    // Initialize input stream and response variables
    String data = "";
      InputStream iStream = null;
      JSONArray infoArray = null;
      
      // Attempt to make the HTTPPOST to the given location
      // DESIGN PATTERN: Exceptions.  In Get/Update/Create, we catch any exception in PHP communication
      //           This also allows us to localize errors that occur during the process
      try {
            HttpClient httpclient = new DefaultHttpClient();
            String suffix = (location == null? (category == null? "getCategories.php" : "getBuildings.php") : "getLocations.php");
            HttpPost httppost = new HttpPost(GET_LOCATIONS_ROOT + suffix);
            
            // If the location is not null, this is a request for items in a category
            if (location != null) {
              
            List<BasicNameValuePair> nameValuePairs = new ArrayList<BasicNameValuePair>();            
            nameValuePairs.add(new BasicNameValuePair("cat", category));
            
            // If the itemName is not null, this is a request for school supplies
            if (item != null) {
              nameValuePairs.add(new BasicNameValuePair("item", item));
            }
            
            // Add the lat and long of the user's location
            nameValuePairs.add(new BasicNameValuePair("lat", location.getLatitudeE6()+""));
            nameValuePairs.add(new BasicNameValuePair("long", location.getLongitudeE6()+""));
                
            httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
            }
            
            HttpResponse response = httpclient.execute(httppost);
            HttpEntity entity = response.getEntity();
            iStream = entity.getContent();
      } catch(Exception e) {
          Log.e("log_tag", "Error in http connection " + e.toString());
      }
      
      // Attempt to convert the response into a string
      try {
            BufferedReader reader = new BufferedReader(new InputStreamReader(iStream,"iso-8859-1"),8);
            StringBuilder sb = new StringBuilder();
            String line = null;
            while ((line = reader.readLine()) != null) {
              sb.append(line + "\n");
            }
            iStream.close();
     
            data = sb.toString();
      } catch(Exception e) {
          Log.e("log_tag", "Error converting result " + e.toString());
      }
      
      // Now try to convert it to a JSONArray
      try {
        
        // If the category is null, we need to retrieve a comma separated list
        if (category == null) {
          JSONTokener jsontok = new JSONTokener(data);
          infoArray = CDL.rowToJSONArray(jsontok);
        } else {
          infoArray = new JSONArray(data);
        }
    } catch (JSONException e) {
      Log.e("log_tag", "Error converting response to JSON " + e.toString());
    }

      return infoArray;
  }
}