Skip to main content

Push Notification to delete local data

Power of PUSH

In this blog I will explain how you can use Push Notification to delete data saved in local SQLLite database.

What I'll explain :
  1. Simple MAF app, which will create a table and put some data in it while loading for the first time.
  2. It will have one page to display the data stored in the local database.
  3. I will configure MCS to send Push notification to the MAF app.
  4. On receive the MAF app will fire a delete statement to remove all the data form local database.
Requirements :
  1. MAF 2.2
  2. MCS or any push server
GitHub link : https://github.com/sohamda/PushAndDelete/
The basic architecture of this solution is :



Step #1 : Configure MCS Backend with Google Project ID and Prepare your MAF code

You need to create a Google project and enable messaging API. Then configure the MCS backend with the details. Then create your MAF application to register with MCS to receive push notifications.

Step #2 : Create table and add sample data while app loaded for the first time

Add a DB script to create a table and add some sample data, put the script inside ApplicationController > META-INF

initializedb.sql
PRAGMA auto_vacuum = FULL;
CREATE TABLE PUSH_AND_DEL (PAD_ID NUMBER(6) PRIMARY KEY, FIRST_NAME VARCHAR2(20), LAST_NAME VARCHAR2(25) NOT NULL);
INSERT INTO PUSH_AND_DEL (PAD_ID, FIRST_NAME, LAST_NAME) VALUES (100,'Natalie','Cole');
INSERT INTO PUSH_AND_DEL (PAD_ID, FIRST_NAME, LAST_NAME) VALUES (101,'Dean','Jones');
INSERT INTO PUSH_AND_DEL (PAD_ID, FIRST_NAME, LAST_NAME) VALUES (102,'Billy','Joe Royal');
INSERT INTO PUSH_AND_DEL (PAD_ID, FIRST_NAME, LAST_NAME) VALUES (103,'David','Bowie');


In LifeCycleListenerImpl.start() : try executing a select * query on the one of tables your app is/will be using, if it throws an SQLException create required tables and fill in with sample data.

For example : my app is using the table PUSH_AND_DEL. Also I have used "DBConnectionFactory" class, it is a custom class to initialize and create a connection. (detailed code is in the GitHub link)

try {
  Statement stat = DBConnectionFactory.getConnection().createStatement();
  ResultSet rs = stat.executeQuery("SELECT PAD_ID FROM PUSH_AND_DEL WHERE PAD_ID = -1;");
} catch (SQLException sqle) {
   try {
     initializeDatabaseFromScript();
   } catch (Exception e) {
     e.printStackTrace();
  }
}

initializeDatabaseFromScript() : Will initialize the DB, create table and put sample data in it. the snippet is as follows :

Connection conn = DBConnectionFactory.getConnection();

conn.setAutoCommit(false);

scriptStream = Thread.currentThread().getContextClassLoader().getResourceAsStream("META-INF/initializedb.sql");
BufferedReader scriptReader = new BufferedReader(new InputStreamReader(scriptStream));
String nextLine;
StringBuffer nextStatement = new StringBuffer();

// The while loop iterates over all the lines in the SQL script,
// assembling them into valid SQL statements and executing them as
// a terminating semicolon is encountered
Statement stmt = conn.createStatement();
while ((nextLine = scriptReader.readLine()) != null) {
    if (nextLine.length() < 1) {
        continue;
    }
    nextStatement.append(nextLine);
    if (nextLine.endsWith(";")) {
        stmt.execute(nextStatement.toString());
        nextStatement = new StringBuffer();
    }
}


conn.commit();

 

Step #3 : Create a AMX page to display the data stored in the local DB

I have created one feature linked to an TaskFlow which has only one view associated with it to display the data stored in the local DB in a list view.




Step #4 : Update PushNotificationListener to delete data on receive of push message

Call the below snippet from PushNotificationListener.onMessage().

Connection conn = DBConnectionFactory.getConnection();
Statement stmt = conn.createStatement();
stmt.executeQuery("DELETE FROM PUSH_AND_DEL");
conn.commit();

You should add some extra logic to invoke the delete operation on receive of a special push message, i.e., some pre-defined text. Because your app should be able to distinguish between normal push message and delete push message.

The before and after receiving the push message, this is how it looks on my mobile 



Comments

  1. The push notification will appear on the app? Is there any way to not show the notification?

    ReplyDelete
    Replies
    1. Yes it will appear on the app. I don't think you can suppress that. Could be some custom code in onMessage(), but I haven't tried it.

      Delete
    2. Here is the suggestion to a new post "How to sent silent push".

      Delete

Post a Comment

Popular posts from this blog

ADF Utility : Find UIComponent from Managed Bean

Many a times, it is required to find an UIComponent from ADF managed bean, to do something with it, for example : change the value of an af:outputText, change readOnly property of an af:inputText etc.     private UIComponent getUIComponent(String id) {                  FacesContext facesCtx = FacesContext.getCurrentInstance();          return findComponent(facesCtx.getViewRoot(), id);     }          private UIComponent findComponent(UIComponent base, String id) {                 if (id.equals(base.getId())) {             return base;         }         UIComponent children = null;         UIComponent result = null;         Iterator childrens = base.getFacetsAndChildren();         while (childrens.hasNext() && (result == null)) {             children = (UIComponent)childrens.next();             if (id.equals(children.getId())) {                 result = children;                 break;             }             result = findComponent(children, id);             if (result != nu

Exception Handling in ADF

This blog will give you an overview on how you can successfully deal with unhandled Runtime exceptions in an ADF application. This will give you an idea of: How to catch the unhandled exceptions. Write a separate log file with stacktrace and thread dumps. Redirect the user to an static error page #1. Catch unhandled exceptions :  Create a class "MyExceptionHandler" which extends : oracle.adf.view.rich.context.ExceptionHandler. Override handleException() method.     public void handleException(FacesContext facesContext, Throwable throwable, PhaseId phaseId) throws Throwable {         // this method is going to create a separate file with stacktrace and thread dumps         writeException(throwable);         // redirect to error page         redirectToErrorPage(facesContext);     }  Create a folder "services" inside : ViewController\src\META-INF and then create a file named "oracle.adf.view.rich.context.ExceptionHandler". In the file, add

Font Awesome with ADF

For people who are not aware of Font Awesome , it  gives you scalable vector icons that can instantly be customized — size, color, drop shadow, and anything that can be done with the power of CSS. Their whole icon library is based on CSS not Images. Recently, we had to build a tree table based on Webcenter content's folder and file structure. And we needed to show proper icons for files (pdf, word etc.) and folders. Which should look like this   We choose Font Awesome, because it is scalable and easy to use. But front-end was ADF, so we were a bit sceptical  about how to integrate both. Turned out it was quite easy. Special thanks for Casper Overweter to do the implementation. 1. Create an ADF Skin : Create a custom skin, via New > Gallery. Base it on alta-v1 skin. 2. Download Font Awesome : Download the zip form their website . It's free. Unzip it inside the "customSkin" folder. Next to your CSS. 3. Extend Font Awesome to your c