FilteredRowSet is a disconnected RowSet implementation used to display only the rows that satisfy a particular filtering condition. It extends WebRowSet and allows filtering without requiring a separate SQL query for every filtering operation.
For example, if the RowSet contains all employees, a filter can be used to display only employees from the IT department.
Key Features
- Works in disconnected mode.
- Supports filtering of rows.
- Uses a
Predicateobject to define filtering rules. - Can reduce the amount of data that needs to be processed by the application.
- The filter can be applied dynamically.
Program Using FilteredRowSet
FilteredRowSet is used to filter rows according to a condition. It works in disconnected mode and uses a Predicate object to determine which rows should be visible.
import javax.sql.RowSet;
import javax.sql.rowset.FilteredRowSet;
import javax.sql.rowset.RowSetProvider;
import javax.sql.rowset.Predicate;
import java.sql.SQLException;
public class FilteredRowSetExample {
public static void main(String[] args) {
try {
// Create FilteredRowSet
FilteredRowSet rowSet =
RowSetProvider.newFactory()
.createFilteredRowSet();
// Set database properties
rowSet.setUrl(
"jdbc:mysql://localhost:3306/jdbc_demo");
rowSet.setUsername("root");
rowSet.setPassword("password");
rowSet.setCommand(
"SELECT employee_id, employee_name, " +
"department, salary FROM employee");
// Retrieve all data
rowSet.execute();
// Create filter
Predicate filter = new Predicate() {
public boolean evaluate(
RowSet rs) {
try {
String department =
rs.getString("department");
return "IT".equalsIgnoreCase(
department);
} catch (SQLException e) {
return false;
}
}
public boolean evaluate(
Object value,
int column)
throws SQLException {
return true;
}
public boolean evaluate(
Object value,
String columnName)
throws SQLException {
return true;
}
};
// Apply filter
rowSet.setFilter(filter);
System.out.println(
"Employees in IT Department");
System.out.println(
"-----------------------------");
// Display filtered records
while (rowSet.next()) {
System.out.println(
rowSet.getInt("employee_id") + " " +
rowSet.getString("employee_name") + " " +
rowSet.getString("department") + " " +
rowSet.getDouble("salary"));
}
rowSet.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}Execution and Output:
PS D:\test> javac -classpath ".;D:\test\mysql-connector.jar" FilteredRowSetExample.java
PS D:\test> java -classpath ".;D:\test\mysql-connector.jar" FilteredRowSetExample
Employees in IT Department
-----------------------------
107 Suresh IT 46500.0
110 Sai IT 45000.0Code language: CSS (css)