DatabaseUtil.java

package com.core.storage;

import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.database.sqlite.SQLiteStatement;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;

public class DatabaseUtil {
 
    private static DatabaseHelper mOpenHelper = null;
 
    private static Context context;
 
    private static final String DATABASE_RESOURCE_FILE_NAME = "database.sql";
    /**
     * Initialize the DatabaseUtil instance for the app
     *
     *            {@link Context}
     *
     *            databasename
     */
    public static void init(Context mcontext, String databasename, int version, DatabaseConfig config) {
 
        if (mOpenHelper == null) {
            context = mcontext;
            mOpenHelper = new DatabaseHelper(mcontext, databasename, version, config);
             
            try {
                mOpenHelper.getWritableDatabase().close();
            }catch (Exception e) {
                 
            }
 
        }
 
    }
 
    /**
     * this method is used to get the current database instance
     * 
     * @return SQLiteDatabase instance to access current database
     * @throws DbException 
     */
    public static SQLiteDatabase getDatabaseInstance() throws DbException {
         
        if (mOpenHelper == null) throw new DbException("DatabaseUtil.init() is not called.");
         
        return mOpenHelper.getWritableDatabase();
 
    }
 
    /**
     * Use this static method to release database related resource. Pass
     * <code>null</code> if not particular argument is not applicable.
     * 
     * @param
     *            {@link SQLiteDatabase}
     * @param stmt
     *            {@link  }
     * @param cursor
     *            {@link Cursor}
     */
    public static void closeResource(SQLiteStatement stmt,
            Cursor cursor) {
 
        if (stmt != null) {
            try {
                stmt.close();
            } catch (Exception e) {
            }
        }
 
        if (cursor != null) {
            try {
                cursor.close();
            } catch (Exception e) {
            }
        }
 
         
    }
 
    /**
     * This class helps open, create, and upgrade the database file.
     */
    public static class DatabaseHelper extends SQLiteOpenHelper {
 
        DatabaseConfig config = null;
         
        public DatabaseHelper(Context context, String datbaseName, int version, DatabaseConfig config) {
            super(context, datbaseName, null, version);
            this.config = config;
        }
 
        @Override
        public void onCreate(SQLiteDatabase db) {
            executeStatement(db);
             
            if(config != null) {
                try {
                    config.onCreate(db);
                } catch (Exception e) {
                }
            }
        }
 
        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
            if(config != null) {
                try {
                    config.onUpgrade(db);
                } catch (Exception e) {
                }
            }
             
            onCreate(db);
        }
    }
     
    /**
     * executes the statements from the file which is in the asset folder
     * if line in the file starts with # then it consider it as the comments 
     * @param db 
     */
    private static void executeStatement(SQLiteDatabase db)
    {
        try {
            InputStream inputStream = context.getAssets().open(DATABASE_RESOURCE_FILE_NAME);
            if(inputStream != null) {
                 
                BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
                String statement;
                while((statement = reader.readLine()) != null) {
                    if(statement.trim().length() > 0 && !statement.startsWith("#")) {
                        db.execSQL(statement);  
                    }                       
                }
                 
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
     
    /**
     * Delete Database and releases all resources.
     */
    public static void deleteDatabase(String dbName) {
         
        if(mOpenHelper != null) {
            mOpenHelper.close();
            mOpenHelper = null;
            context.deleteDatabase(dbName);
            context = null;         
        }       
    }
     
     
    /**
     * Close DatabaseUtil and releases all resources.
     */
    public static void destroy() {
         
        if(mOpenHelper != null) {
            mOpenHelper.close();
            mOpenHelper = null;
            context = null;         
        }       
    }
     
    public static DatabaseHelper getmOpenHelper() {
        return mOpenHelper;
    }
     
}