Practical Java Source Code

class Employee { private String EmpName; private String EmpTitle; private int EmpNumber; public Employee() {} public Employee(String name, String title, int number) { EmpName = name; EmpTitle = title; EmpNumber = number; } public int salary() { int salary = 100; //query database based on Employee object to get salary. //salary = querydb(this); return salary; } public void setName(String name) { EmpName = name; } public void setTitle(String title) { EmpTitle = title; } public void setNumber(int number) { EmpNumber = number; } public void reinitialize(String name, String title, int number) { EmpName = name; EmpTitle = title; EmpNumber = number; } //... } class test { public int computePayroll1(String[] name, String[] title, int[] number) { int size = name.length; int totalPayroll = 0; if (size > 0) { Employee emp = new Employee(); for (int i=0; i<size; i++) { emp.setName(name[i]); emp.setTitle(title[i]); emp.setNumber(number[i]); totalPayroll += emp.salary(); } } return totalPayroll; } public int computePayroll2(String[] name, String[] title, int[] number) { int size = name.length; int totalPayroll = 0; if (size > 0) { Employee emp = new Employee(); for (int i=0; i<size; i++) { emp.reinitialize(name[i], title[i], number[i]); totalPayroll += emp.salary(); } } return totalPayroll; } public static void main(String args[]) { int val = Integer.parseInt(args[0]); test t = new test(); String[] name = new String[10]; String[] title = new String[10]; int[] number = new int[10]; for (int i=0; i<10; i++) { name[i]="Peter"; title[i]="Advisory"; number[i]= 123; } System.gc(); long start = System.currentTimeMillis(); for (int i=0; i<val; i++) t.computePayroll1(name, title, number); long end = System.currentTimeMillis(); System.out.println("normal reuse" + (end-start)); long num = end-start; System.gc(); start = System.currentTimeMillis(); for (int i=0; i<val; i++) t.computePayroll2(name, title, number); end = System.currentTimeMillis(); System.out.println("reinit method " + (end-start)); num = ((num-(end-start))*100)/num; System.out.println("reinit is " + num + " percent faster"); } }