Performing Partial Rollback (Undo Changes) operation in ADF, Stay on current row after rollback

Hello All ,
This post talks about a common requirement of using partial rollback in ADF

Suppose there is two tables on page Departments and Employees, and i have changed one row in Departments table and same time created a row in Employees table, now i want to rollback the changes done in Departments table only

In this case if i use default Rollback operation then it will not only undo the changes of Department table but also remove the newly created row of Employees table
but this was not my purpose.

So to do this kind of things we can use partial rollback operation

• I have created a fusion web application (Model & VC) using Departments & Employees Table of Oracle's default HR Schema



• Now drop departments & employees VO on page with it's default operations (CreateInsert, Delete, Execute, Commit & Rollback) and a button to execute partial rollback of departments ViewObject





• Here in this example i am creating partial rollback for Departments VO only, so to do this add a new transient attribute in Departments Vo to get current state of each row







• How to get state of each row , in RowImpl class of departments ViewObject , write this code in getter of transient attribute or see my previous blog-post Identifying Modified/newely added row in af:table, get all modified rows of viewobject in bean



    /**
     * Gets the attribute value for the calculated attribute RowStatusTrans.
     * @return the RowStatusTrans
     */
    public Integer getRowStatusTrans() {
        /*here row is reference variable of collection, this expression returns an int value if it is
         2-Modified
         0-New
         1-Unmodified
        -1-Initialized
        */
        byte entityState = this.getEntity(0).getEntityState();
        return new Integer(entityState);
    }



• Have created a method to remove newly added row , and to undo changes in existing rows of departments VO in Impl class



    /**Method to revert changes of current row
     * @param curRow
     */
    public void revertChangesCurrentRow(Row curRow) {
        if (curRow != null) {
            curRow.refresh(Row.REFRESH_UNDO_CHANGES | Row.REFRESH_WITH_DB_FORGET_CHANGES);
        }
    }

    /**Method to check whether row should be removed or not 
     * If it is new - removed
     * If old one- Undo Changes
     * */
    public void revertOrremoveRowValues() {
        ViewObject deptVo = this;
        RowSetIterator deptIter = deptVo.createRowSetIterator(null);
        while (deptIter.hasNext()) {
            Row nextRow = deptIter.next();
            if (nextRow.getAttribute("RowStatusTrans") != null) {
                Integer rowStatus = (Integer) nextRow.getAttribute("RowStatusTrans");
                if (rowStatus == 2) {
                    System.out.println("Modified Rows-" + nextRow.getAttribute("DepartmentId"));
                    revertChangesCurrentRow(nextRow);
                } else if (rowStatus == 0) {
                    System.out.println("New Row Removed");
                    nextRow.remove();
                }
            }
        }
        this.executeQuery();
    }



• To read more about REFRESH_UNDO_CHANGES and other constants -http://docs.oracle.com/cd/B14099_19/web.1012/b14022/oracle/jbo/Row.html
• Exposed this method to client and added it to page bindings then called it on Partial Rollback button






• After running application, i have changed some rows of Departments table and created a new row in employees table





• Now if i use rollback, it will also remove the new row of employees table, this is the dis-advantage of using rollback





• Again i have changed some rows of departments table and created a new row in employees table





• Now see when i click on partial rollback button, it will only undo changes done in department table and employee table is untouched





• And to stay on current row after partial rollback operation just remove executeQuery from revertOrremoveRowValues() method

Download Sample App
Cheers :-)  Happy Learning

Executing SQL query in an ADF Application using DBTransaction & JDBC DataSource

hello all,
this post is about executing SQL query in your ADF Application
Sometimes we need to execute some query in our managed bean or any of implementation class of Model, this is quite easy

• I have a fusion web application having connection with hr schema of Oracle DB
• now i have to get Max Department Id of Departments Table using this statement



SELECT max(DEPARTMENT_ID) CODE FROM DEPARTMENTS



• So to execute this query i have created a method in AMImpl class using DBTransaction



    /**Method to Execute DB SQL Query using DBTransaction
     * @param query
     * @return
     */
    protected Integer executeQuery(String query) {
        ResultSet rs;
        Integer code = null;
        try {
            rs = getDBTransaction().createStatement(0).executeQuery(query);
            if (rs.next()) {
                code = ((BigDecimal) rs.getObject(1)).intValue();
            }

            rs.close();
            return code;

        } catch (SQLException e) {
            throw new JboException(e);
        }
    }



• now called this method and passed my SQL statement





        Integer deptID = executeQuery("SELECT max(DEPARTMENT_ID) CODE FROM DEPARTMENTS");
        System.out.println("Department Id-" + deptID);


And Output is-



• Second way is by using JDBC DataSource , for this first we have to get Connection using DataSource Name- see this method



    /**Method to get Connection using JDBC DataSource Name
     * @param dsName
     * @return
     * @throws NamingException
     * @throws SQLException
     */
    public static Connection getConnectionDS(String dsName) throws NamingException, SQLException {
        Connection con = null;
        DataSource datasource = null;

        Context initialContext = new InitialContext();
        if (initialContext == null) {
        }
        datasource = (DataSource) initialContext.lookup(dsName);
        if (datasource != null) {
            con = datasource.getConnection();
        } else {
            System.out.println("Failed to Find JDBC DataSource.");
        }
        return con;
    }



• Now after getting connection , we can execute SQL query using Statement or PreparedStatement
• Go to your ApplicationModule to get DataSource Name, in Configuration tab open AMLocal

•  Copy DataSource Name , and use it to get Connection and to execute query



        Connection con = null;
        try {
            con = getConnectionDS("java:comp/env/jdbc/APPDS");
        } catch (SQLException e) {
        } catch (NamingException e) {
        }
        try {
            PreparedStatement stmt = con.prepareStatement("SELECT * FROM DEPARTMENTS");
            ResultSet rs = stmt.executeQuery();
            while (rs.next()) {
                System.out.println("Department Id-" + rs.getInt(1) + " and Department Name-" + rs.getString(2));
            }

            rs.close();


        } catch (SQLException e) {
            throw new JboException(e);
        }



• After executing see the output- 

 Cheers :-) happy coding

Iterating ViewObject vertically (get all attributes of ViewObject) programmatically

Hello All,
This post talks about a requirement of getting all attributes (column names) of a viewObject programmatically

• Create a fusion web application and business component using department table

• you can see all attributes in  Departments entity object

• Now to get ViewObject's attributes name , there is a method written in AMImpl class , see it, i have added a facesMessage to show all names on a Message Board





    /**Method to get all attributes of a viewObject
     * */
    public void iterateVoVertically() {
        ViewObjectImpl vo = this.getDepartments1();
        ViewAttributeDefImpl[] attrDefs = vo.getViewAttributeDefImpls();
        int count = 0;
        StringBuilder infoMsg =
            new StringBuilder("<html><body><b><p style='color:red'> Attribute of Department ViewObject are-</p></b>");
        infoMsg.append("<ul>");


        for (ViewAttributeDefImpl attrDef : attrDefs) {
            byte attrKind =
                attrDefs[count].getAttributeKind(); //checks attribute kind for each element in an array of AttributeDefs
            if (attrKind != AttributeDef.ATTR_ASSOCIATED_ROW && attrKind != AttributeDef.ATTR_ASSOCIATED_ROWITERATOR) {
                String columnName = attrDef.getName();
                infoMsg.append("<li> <b>" + attrDef.getName() + "</b></li>");
                System.out.println("Column Name-" + columnName);
            }
        }
        infoMsg.append("</ul><br>");
        infoMsg.append("</body></html>");
        FacesMessage msg = new FacesMessage(infoMsg.toString());
        msg.setSeverity(FacesMessage.SEVERITY_INFO);
        FacesContext.getCurrentInstance().addMessage(null, msg);
    }



• I have called this method through page binding and AM Client on a button of page

• now on click of button all attributes of Departments ViewObject are shown in FacesMessage, you can use it in your code

 Cheers :-)