Android Open Source - Fast Database

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License

The source code is released under:

GNU General Public License

Java Source Code

package com.example.fast;
/*from w w w.j av  a2  s  . c  o  m*/
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;

/**
 * Object that represents the database.  Abstracts away cursor and contentvalues with simple methods to create and update entries into the database.
 *
 */
public class Database { 

  private DatabaseHelper dbHelper;  
    private SQLiteDatabase database;  
    public final static String TABLE= "fast_table"; 
    public final static String ID = "_id"; 
    public final static String AVERAGE_SPEED = "average_speed", MAX_SPEED = "max_speed", DISTANCE = "distance", USERNAME = "username", AVERAGE_HEARTRATE = "average_heartrate"; 
    
  public Database(Context context){  
      dbHelper = new DatabaseHelper(context);  
      database = dbHelper.getWritableDatabase();  
  }
  
  /**
   *  If user not seen before, create them with all data initialized to 0. */
  public long createRecord(String userName){
    
    /* Create row */
    if(userName != null){
      return createRecords(userName, 0, 0, 0, 0);
    }
    else return -1L;
  }

  /**
   *   Create a bew record with the following initial data.
   */
  private long createRecords(String name, double averageSpeed, double maxSpeed, double distance, double heartrate){  
     
    /* TODO: Query and reinsert */
    
    ContentValues values = new ContentValues();    
     values.put(USERNAME, name);  
     values.put(AVERAGE_SPEED, averageSpeed);  
     values.put(MAX_SPEED, maxSpeed);  
     values.put(DISTANCE, distance);  
     values.put(AVERAGE_HEARTRATE, heartrate);
     
     return database.insert(TABLE, null, values);  
  }
  
  /* Updates current values with new ones */
  public long updateRecords(String userName, double averageSpeed, double maxSpeed, double distance, double heartrate){  
       
    /* Query and reinsert */
    Cursor cursor = selectRecords(userName);
    cursor.moveToFirst();
    if(!cursor.isAfterLast()){    
      /* Annoying NAN check */
      double averageSpeedTmp;
      if(averageSpeed + cursor.getDouble(cursor.getColumnIndex(AVERAGE_SPEED)) == Double.NaN){
        averageSpeedTmp = 0;
      }
      else{
        averageSpeedTmp = (averageSpeed + cursor.getDouble(cursor.getColumnIndex(AVERAGE_SPEED)))/2;
      }
      
      ContentValues values = new ContentValues();    
       values.put(USERNAME, userName);  
       values.put(AVERAGE_SPEED, averageSpeedTmp);  
       values.put(MAX_SPEED, maxSpeed > cursor.getDouble(cursor.getColumnIndex(MAX_SPEED)) ? maxSpeed : cursor.getDouble(cursor.getColumnIndex(MAX_SPEED)));  
       values.put(DISTANCE, distance + cursor.getDouble(cursor.getColumnIndex(DISTANCE)));  
       values.put(AVERAGE_HEARTRATE, (heartrate + cursor.getDouble(cursor.getColumnIndex(AVERAGE_HEARTRATE)))/2);
       
       return database.update(TABLE, values, null, null);  
    }

    return createRecords(userName, averageSpeed, maxSpeed, distance, heartrate);

  }
  
  /**
   * 
   * @param userName Record to select (This user)
   * @return Cursor of all rows found (should only be 1).
   */
  public Cursor selectRecords(String userName) {
    
         String[] cols = new String[] {USERNAME, AVERAGE_SPEED, MAX_SPEED, DISTANCE, AVERAGE_HEARTRATE};  
         Cursor mCursor = database.query(true, TABLE, cols, USERNAME + " = \"" + userName + "\"", null, null, null, null, null);  
         
       return mCursor; // iterate to get each value.
  }
  
  /**
   * 
   * @param name Name of user to grab stats of.
   * @return A statistics object filled with this user's data.
   */
  public Statistics selectStatistics(String name){
    Cursor cursor = selectRecords(name);
    Statistics stat = new Statistics();
    stat.setAverageHeartrate(0.0);
    cursor.moveToFirst();
    
    if(!cursor.isAfterLast()){
      
      stat.setAverageSpeed(cursor.getDouble(cursor.getColumnIndex(AVERAGE_SPEED)));
      stat.setMaxSpeed(cursor.getDouble(cursor.getColumnIndex(MAX_SPEED)));
      stat.setDistanceTravelled(cursor.getDouble(cursor.getColumnIndex(DISTANCE)));
      stat.setAverageHeartrate(cursor.getDouble(cursor.getColumnIndex(AVERAGE_HEARTRATE)));
    }
    return stat;
  }
}

Java Source Code List

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