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
