I have a sqlite helper class which basically handles all the DML operations wrt to a sqlite db. I now have a requirement to send this sqlite data (or particular rows from the tables of the db) to a server and need to serialize the data to xml before doing so. One way I have found out is to wrap the db with a content provider, expose the endpoint, serialize the data and send it. How do I wrap the SQLite helper to do this ?
EDIT: I need to just expose the endpoint and dont really need to override DML operations. Is there a way I can do this without wrapping it in content provider? I dont need to expose data to other apps.
The helper is basically in this form
package com.MyPackage;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.UUID;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
public class AnyDBAdapter {
private static final String TAG = "AnyDBAdapter";
private DatabaseHelper mDbHelper;
private static SQLiteDatabase mDb;
//make sure this matches the
//package com.MyPackage;
//at the top of this file
private static String DB_PATH = "/data/data/com.MyPackage/databases/";
//make sure this matches your database name in your assets folder
// my database file does not have an extension on it
// if yours does
// add the extention
private static final String DATABASE_NAME = "data";
//Im using an sqlite3 database, I have no clue if this makes a difference or not
private static final int DATABASE_VERSION = 3;
private final Context adapterContext;
public AnyDBAdapter(Context context) {
this.adapterContext = context;
}
public AnyDBAdapter open() throws SQLException {
mDbHelper = new DatabaseHelper(adapterContext);
try {
mDbHelper.createDataBase();
} catch (IOException ioe) {
throw new Error("Unable to create database");
}
try {
mDbHelper.openDataBase();
} catch (SQLException sqle) {
throw sqle;
}
return this;
}
//Usage from outside
// AnyDBAdapter dba = new AnyDBAdapter(contextObject); //in my case contextObject is a Map
// dba.open();
// Cursor c = dba.ExampleSelect("Rawr!");
// contextObject.startManagingCursor(c);
// String s1 = "", s2 = "";
// if(c.moveToFirst())
// do {
// s1 = c.getString(0);
// s2 = c.getString(1);
// } while (c.moveToNext());
// dba.close();
public Cursor ExampleSelect(string myVariable)
{
String query = "SELECT locale, ? FROM android_metadata";
return mDb.rawQuery(query, new String[]{myVariable});
}
//Usage
// AnyDBAdatper dba = new AnyDBAdapter(contextObjecT);
// dba.open();
// dba.ExampleCommand("en-CA", "en-GB");
// dba.close();
public void ExampleCommand(String myVariable1, String myVariable2)
{
String command = "INSERT INTO android_metadata (locale) SELECT ? UNION ALL SELECT ?";
mDb.execSQL(command, new String[]{ myVariable1, myVariable2});
}
public void close() {
mDbHelper.close();
}
private static class DatabaseHelper extends SQLiteOpenHelper {
Context helperContext;
DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
helperContext = context;
}
@Override
public void onCreate(SQLiteDatabase db) {
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
Log.w(TAG, "Upgrading database!!!!!");
//db.execSQL("");
onCreate(db);
}
public void createDataBase() throws IOException {
boolean dbExist = checkDataBase();
if (dbExist) {
} else {
//make sure your database has this table already created in it
//this does not actually work here
/*
* db.execSQL("CREATE TABLE IF NOT EXISTS \"android_metadata\" (\"locale\" TEXT DEFAULT 'en_US')"
* );
* db.execSQL("INSERT INTO \"android_metadata\" VALUES ('en_US')"
* );
*/
this.getReadableDatabase();
try {
copyDataBase();
} catch (IOException e) {
throw new Error("Error copying database");
}
}
}
public SQLiteDatabase getDatabase() {
String myPath = DB_PATH + DATABASE_NAME;
return SQLiteDatabase.openDatabase(myPath, null,
SQLiteDatabase.OPEN_READONLY);
}
private boolean checkDataBase() {
SQLiteDatabase checkDB = null;
try {
String myPath = DB_PATH + DATABASE_NAME;
checkDB = SQLiteDatabase.openDatabase(myPath, null,
SQLiteDatabase.OPEN_READONLY);
} catch (SQLiteException e) {
}
if (checkDB != null) {
checkDB.close();
}
return checkDB != null ? true : false;
}
private void copyDataBase() throws IOException {
// Open your local db as the input stream
InputStream myInput = helperContext.getAssets().open(DATABASE_NAME);
// Path to the just created empty db
String outFileName = DB_PATH + DATABASE_NAME;
// Open the empty db as the output stream
OutputStream myOutput = new FileOutputStream(outFileName);
// transfer bytes from the inputfile to the outputfile
byte[] buffer = new byte[1024];
int length;
while ((length = myInput.read(buffer)) > 0) {
myOutput.write(buffer, 0, length);
}
// Close the streams
myOutput.flush();
myOutput.close();
myInput.close();
}
public void openDataBase() throws SQLException {
// Open the database
String myPath = DB_PATH + DATABASE_NAME;
mDb = SQLiteDatabase.openDatabase(myPath, null,
SQLiteDatabase.OPEN_READWRITE);
}
@Override
public synchronized void close() {
if (mDb != null)
mDb.close();
super.close();
}
}
}
If you don’t need to expose a subset of your data to other apps on the device (say read only, or a single table), you generally don’t need a content provider. Simply access your data using your helper class and then transform it as necessary. In your case you would need to use one of the XML APIs to generate the documents your server expects. There is nothing that will do this automatically for you though, if that is what you are looking for (such as JAXB, etc. other Java platforms).