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Applying Enterprise JavaBeans 2nd
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A.2 EnrollmentBean Source CodeHere is the complete class implementation for the EnrollmentBean session bean coded for the session bean application example in Chapter 4. Code Example A.2 EnrollmentBean Source Code
package com.star.benefits;
import javax.ejb.*;
import java.util.Date;
import java.io.Serializable;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.sql.DataSource;
import java.sql.SQLException;
import com.star.benefits.db.DBQueryEmployee;
import com.star.benefits.db.DBQuerySelection;
import com.star.benefits.db.DBInsertSelection;
import com.star.benefits.db.DBUpdateSelection;
// The Employee class is used internally to represent the employee
// information in the instance's conversational state.
//
class Employee implements Serializable {
int emplNumber;
String firstName;
String lastName;
Date birthDate;
Date startDate;
}
// The Selection class is used internally to represent the benefits
// selections in the instance's conversational state.
//
class Selection implements Serializable {
int emplNumber;
int coverage;
String medicalPlanId;
String dentalPlanId;
boolean smokerStatus;
}
// EnrollmentBean is a stateful session bean that implements
// the benefits enrollment business process.
//
public class EnrollmentBean implements SessionBean
{
private final static String[] coverageDescriptions = {
"Employee Only",
"Employee and Spouse",
"Employee, Spouse, and Children"
};
// Tables of Java classes that are used for calculation of
// of cost of medical and dental benefits
private HealthPlan[] medicalPlans;
private HealthPlan[] dentalPlans;
// Portion of the benefits cost paid by the employee (A
// real-life application would read this value from the
// database.)
private double employeeCostFactor = 0.10;
// Employee number that uniquely identifies an employee
private int employeeNumber;
// Employee information read from database
private Employee employee;
// Employee's current benefits selections
private Selection selection;
// Indication if beans need to create selection record
private boolean createSelection;
// The following variables are calculated values and are
// used for programming convenience.
private int age; // employee's age
private int medicalSelection = -1; // index to medicalPlans
private int dentalSelection = -1; // index to dentalPlans
private double totalCost; // total benefits cost
private double payrollDeduction; // payroll deduction
// JDBC data sources
private DataSource employeeDS; // Employee database
private DataSource benefitsDS; // Benefits database
// public no-arg constructor
public EnrollmentBean() { }
// business methods
// Get employee information.
public EmployeeInfo getEmployeeInfo() {
return new EmployeeInfo(employeeNumber,
employee.firstName, employee.lastName);
}
// Get coverage options.
public Options getCoverageOptions() {
Options opt = new Options(coverageDescriptions.length);
opt.setOptionDescription(coverageDescriptions);
opt.setSelectedOption(selection.coverage);
return opt;
}
// Set selected coverage option.
public void setCoverageOption(int choice)
throws EnrollmentException {
if (choice >= 0 && choice < coverageDescriptions.length) {
selection.coverage = choice;
} else {
throw new EnrollmentException(
EnrollmentException.INVAL_PARAM);
}
}
// Get list of available medical options.
public Options getMedicalOptions() {
Options opt = new Options(medicalPlans.length);
for (int i = 0; i < medicalPlans.length; i++) {
HealthPlan plan = medicalPlans[i];
opt.setOptionDescription(i, plan.getDescription());
opt.setOptionCost(i,
plan.getCost(selection.coverage,
age, selection.smokerStatus));
}
opt.setSelectedOption(medicalSelection);
return opt;
}
// Set selected medical option.
public void setMedicalOption(int choice)
throws EnrollmentException {
if (choice >= 0 && choice < medicalPlans.length) {
medicalSelection = choice;
selection.medicalPlanId =
medicalPlans[choice].getPlanId();
} else {
throw new EnrollmentException(
EnrollmentException.INVAL_PARAM);
}
}
// Get list of available dental options.
public Options getDentalOptions() {
Options opt = new Options(dentalPlans.length);
for (int i = 0; i < dentalPlans.length; i++) {
HealthPlan plan = dentalPlans[i];
opt.setOptionDescription(i, plan.getDescription());
opt.setOptionCost(i,
plan.getCost(selection.coverage,
age, selection.smokerStatus));
}
opt.setSelectedOption(dentalSelection);
return opt;
}
// Set selected dental option.
public void setDentalOption(int choice)
throws EnrollmentException {
if (choice >= 0 && choice < dentalPlans.length) {
dentalSelection = choice;
selection.dentalPlanId =
dentalPlans[choice].getPlanId();
} else {
throw new EnrollmentException(
EnrollmentException.INVAL_PARAM);
}
}
// Get smoker status.
public boolean getSmokerStatus() {
return selection.smokerStatus;
}
// Set smoker status.
public void setSmokerStatus(boolean status) {
selection.smokerStatus = status;
}
// Get summary of selected options and their cost.
public Summary getSummary() {
calculateTotalCostAndPayrollDeduction();
Summary s = new Summary();
s.setCoverageDescription(
coverageDescriptions[selection.coverage]);
s.setSmokerStatus(selection.smokerStatus);
s.setMedicalDescription(
medicalPlans[medicalSelection].getDescription());
s.setMedicalCost(
medicalPlans[medicalSelection].getCost(
selection.coverage, age,
selection.smokerStatus));
s.setDentalDescription(
dentalPlans[dentalSelection].getDescription());
s.setDentalCost(
dentalPlans[dentalSelection].getCost(
selection.coverage, age,
selection.smokerStatus));
s.setTotalCost(totalCost);
s.setPayrollDeduction(payrollDeduction);
return s;
}
// Update corporate databases with the new selections.
public void commitSelections() {
// Insert new or update existing benefits selection record.
if (createSelection) {
DBInsertSelection cmd1 = null;
try {
cmd1 = new DBInsertSelection(benefitsDS);
cmd1.setEmplNumber(employeeNumber);
cmd1.setCoverage(selection.coverage);
cmd1.setMedicalPlanId(selection.medicalPlanId);
cmd1.setDentalPlanId(selection.dentalPlanId);
cmd1.setSmokerStatus(selection.smokerStatus);
cmd1.execute();
createSelection = false;
} catch (SQLException ex) {
throw new EJBException(ex);
} finally {
if (cmd1 != null)
cmd1.release();
}
} else {
DBUpdateSelection cmd2 = null;
try {
cmd2 = new DBUpdateSelection(benefitsDS);
cmd2.setEmplNumber(employeeNumber);
cmd2.setCoverage(selection.coverage);
cmd2.setMedicalPlanId(selection.medicalPlanId);
cmd2.setDentalPlanId(selection.dentalPlanId);
cmd2.setSmokerStatus(selection.smokerStatus);
cmd2.execute();
} catch (SQLException ex) {
throw new EJBException(ex);
} finally {
if (cmd2 != null)
cmd2.release();
}
}
// Update information in the payroll system.
DeductionUpdateBean deductionBean = null;
try {
deductionBean = new DeductionUpdateBean();
deductionBean.setBenefitsDeduction(employeeNumber,
payrollDeduction);
deductionBean.execute();
} finally {
if (deductionBean != null)
deductionBean.release();
}
}
// Initialize the state of the EmployeeBean instance.
public void ejbCreate(int emplNum) throws EnrollmentException {
employeeNumber = emplNum;
// Obtain values from bean's environment.
readEnvironmentEntries();
// Obtain JDBC data sources from environment.
getDataSources();
// Read employee information.
DBQueryEmployee cmd1 = null;
try {
cmd1 = new DBQueryEmployee(employeeDS);
cmd1.setEmployeeNumber(emplNum);
cmd1.execute();
if (cmd1.next()) {
employee = new Employee();
employee.emplNumber = emplNum;
employee.firstName = cmd1.getFirstName();
employee.lastName = cmd1.getLastName();
employee.startDate = cmd1.getStartDate();
employee.birthDate = cmd1.getBirthDate();
} else {
throw new EnrollmentException(
"no employee record");
}
} catch (SQLException ex) {
throw new EJBException(ex);
} finally {
if (cmd1 != null)
cmd1.release();
}
// Read the previous benefits selections.
DBQuerySelection cmd2 = null;
try {
cmd2 = new DBQuerySelection(benefitsDS);
cmd2.setEmployeeNumber(emplNum);
cmd2.execute();
if (cmd2.next()) {
selection = new Selection();
selection.emplNumber = emplNum;
selection.coverage = cmd2.getCoverage();
selection.medicalPlanId =
cmd2.getMedicalPlanId();
selection.dentalPlanId =
cmd2.getDentalPlanId();
selection.smokerStatus =
cmd2.getSmokerStatus();
createSelection = false;
} else {
// No previous selections exist in
// the database. Initial selections to
// default values.
selection = new Selection();
selection.emplNumber = emplNum;
selection.coverage = 0;
selection.medicalPlanId =
medicalPlans[0].getPlanId();
selection.dentalPlanId =
dentalPlans[0].getPlanId();
selection.smokerStatus = false;
createSelection = true;
}
} catch (SQLException ex) {
throw new EJBException(ex);
} finally {
if (cmd2 != null)
cmd2.release();
}
// Calculate employee's age.
java.util.Date today = new java.util.Date();
age = (int)((today.getTime() -
employee.birthDate.getTime()) /
((long)365 * 24 * 60 * 60 * 1000));
// Translate the medical plan ID to an index
// into the medicalPlans table.
for (int i = 0; i < medicalPlans.length; i++) {
if (medicalPlans[i].getPlanId().equals(
selection.medicalPlanId)) {
medicalSelection = i;
break;
}
}
// Translate the dental plan ID to an index
// into the dentalPlans table.
for (int i = 0; i < dentalPlans.length; i++) {
if (dentalPlans[i].getPlanId().equals(
selection.dentalPlanId)) {
dentalSelection = i;
break;
}
}
}
// Clean up any resource held by the instance.
public void ejbRemove() {
}
// Release state that cannot be preserved across passivation.
public void ejbPassivate() {
// All instance variables are either Serializable or one of the
// special objects that are managed by the container
// (e.g., DataSource).
}
// Reacquire state released before passivation.
public void ejbActivate() {
}
public void setSessionContext(SessionContext sc) {}
// Helper methods follow
// Calculate total benefits cost and payroll deduction.
private void calculateTotalCostAndPayrollDeduction() {
double medicalCost =
medicalPlans[medicalSelection].getCost(
selection.coverage,
age, selection.smokerStatus);
double dentalCost =
dentalPlans[dentalSelection].getCost(
selection.coverage,
age, selection.smokerStatus);
totalCost = medicalCost + dentalCost;
payrollDeduction = totalCost * employeeCostFactor;
}
// Read and process enterprise bean's environment entries.
private void readEnvironmentEntries() {
try {
Context ictx = new InitialContext();
String medicalPlanList = (String)
ictx.lookup("java:comp/env/medicalPlans");
String[] medicalPlanClassNames =
parseClassNames(medicalPlanList);
medicalPlans =
new HealthPlan[medicalPlanClassNames.length];
for (int i = 0; i < medicalPlanClassNames.length; i++) {
medicalPlans[i] = (HealthPlan)Class.forName(
medicalPlanClassNames[i]).newInstance();
}
String dentalPlanList = (String)
ictx.lookup("java:comp/env/dentalPlans");
String[] dentalPlanClassNames =
parseClassNames(dentalPlanList);
dentalPlans =
new HealthPlan[dentalPlanClassNames.length];
for (int i = 0; i < dentalPlanClassNames.length; i++) {
dentalPlans[i] = (HealthPlan)Class.forName(
dentalPlanClassNames[i]).newInstance();
}
} catch (Exception ex) {
ex.printStackTrace();
throw new EJBException(ex);
}
}
private void getDataSources() {
try {
Context ictx = new InitialContext();
employeeDS = (DataSource)ictx.lookup(
"java:comp/env/jdbc/EmployeeDB");
benefitsDS = (DataSource)ictx.lookup(
"java:comp/env/jdbc/BenefitsDB");
} catch (Exception ex) {
ex.printStackTrace();
throw new EJBException(ex);
}
}
// Parse ':' separated class names.
//
private static String[] parseClassNames(String list) {
String[] rv = new String[0];
while (list.length() != 0) {
int x = list.indexOf(':');
String name;
if (x < 0) {
name = list;
list = "";
} else {
name = list.substring(0, x);
list = list.substring(x + 1);
}
if (name.length() == 0) {
continue;
}
String[] orv = rv;
rv = new String[rv.length + 1];
for (int i = 0; i < orv.length; i++)
rv[i] = orv[i];
rv[rv.length - 1] = name;
}
return rv;
}
}
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