Fly weight Factory
/*
Software Architecture Design Patterns in Java
by Partha Kuchana
Auerbach Publications
*/
import java.util.HashMap;
import java.util.StringTokenizer;
import java.util.Vector;
public class FlyweightTest {
public static void main(String[] args) throws Exception {
Vector empList = initialize();
FlyweightFactory factory = FlyweightFactory.getInstance();
for (int i = 0; i < empList.size(); i++) {
String s = (String) empList.elementAt(i);
StringTokenizer st = new StringTokenizer(s, ",");
String name = st.nextToken();
String title = st.nextToken();
String division = st.nextToken();
FlyweightIntr flyweight = factory.getFlyweight(division);
//associate the flyweight
//with the extrinsic data object.
VCard card = new VCard(name, title, flyweight);
card.print();
}
}
private static Vector initialize() {
//for simplicity values are being hardcoded.
Vector v = new Vector();
v.add("name1,title1,North");
v.add("name2,title2,South");
v.add("name3,title1,North");
v.add("name4,title3,East");
v.add("name5,title4,East");
v.add("name6,title2,East");
v.add("name7,title1,West");
v.add("name8,title3,West");
v.add("name9,title1,West");
v.add("name10,title6,South");
v.add("name11,title5,North");
v.add("name12,title1,North");
return v;
}
}
class FlyweightFactory {
private HashMap lstFlyweight;
private static FlyweightFactory factory = new FlyweightFactory();
private FlyweightFactory() {
lstFlyweight = new HashMap();
}
public synchronized FlyweightIntr getFlyweight(String divisionName) {
if (lstFlyweight.get(divisionName) == null) {
FlyweightIntr fw = new Flyweight(divisionName);
lstFlyweight.put(divisionName, fw);
return fw;
} else {
return (FlyweightIntr) lstFlyweight.get(divisionName);
}
}
public static FlyweightFactory getInstance() {
return factory;
}
//Inner flyweight class
private class Flyweight implements FlyweightIntr {
private String company;
private String address;
private String city;
private String state;
private String zip;
private void setValues(String cmp, String addr, String cty, String st,
String zp) {
company = cmp;
address = addr;
city = cty;
state = st;
zip = zp;
}
private Flyweight(String division) {
// values are hard coded
//for simplicity
if (division.equals("North")) {
setValues("CMP", "addr1", "cty1", "st1", "10000");
}
if (division.equals("South")) {
setValues("CMP", "addr2", "cty2", "st2", "20000");
}
if (division.equals("East")) {
setValues("CMP", "addr3", "cty3", "st3", "30000");
}
if (division.equals("West")) {
setValues("CMP", "addr4", "cty4", "st4", "40000");
}
}
public String getCompany() {
return company;
}
public String getAddress() {
return address;
}
public String getCity() {
return city;
}
public String getState() {
return state;
}
public String getZip() {
return zip;
}
}// end of Flyweight
}// end of FlyweightFactory
interface FlyweightIntr {
public String getCompany();
public String getAddress();
public String getCity();
public String getState();
public String getZip();
}
class VCard {
String name;
String title;
FlyweightIntr objFW;
public VCard(String n, String t, FlyweightIntr fw) {
name = n;
title = t;
objFW = fw;
}
public void print() {
System.out.println(name);
System.out.println(title);
System.out.println(objFW.getAddress() + "-" + objFW.getCity() + "-"
+ objFW.getState() + "-" + objFW.getZip());
System.out.println("----------------");
}
}
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