Mega Code Archive
Chain Pattern
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//[C] 2002 Sun Microsystems, Inc.---
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.ArrayList;
import java.io.File;
import java.util.ArrayList;
import java.util.Iterator;
public class RunChainPattern {
public static void main(String [] arguments){
System.out.println("Example for the Chain of Responsibility pattern");
System.out.println();
System.out.println("This code uses chain of responsibility to obtain");
System.out.println(" the owner for a particular ProjectItem, and to");
System.out.println(" build up a list of project details. In each case,");
System.out.println(" a call to the appropriate getter method, getOwner");
System.out.println(" or getDetails, will pass the method call up the");
System.out.println(" project tree.");
System.out.println("For getOwner, the call will return the first non-null");
System.out.println(" owner field encountered. For getDetails, the method");
System.out.println(" will build a series of details, stopping when it");
System.out.println(" reaches a ProjectItem that is designated as a");
System.out.println(" primary task.");
System.out.println();
System.out.println("Deserializing a test Project for Visitor pattern");
System.out.println();
if (!(new File("data.ser").exists())){
DataCreator.serialize("data.ser");
}
Project project = (Project)(DataRetriever.deserializeData("data.ser"));
System.out.println("Retrieving Owner and details for each item in the Project");
System.out.println();
getItemInfo(project);
}
private static void getItemInfo(ProjectItem item){
System.out.println("ProjectItem: " + item);
System.out.println(" Owner: " + item.getOwner());
System.out.println(" Details: " + item.getDetails());
System.out.println();
if (item.getProjectItems() != null){
Iterator subElements = item.getProjectItems().iterator();
while (subElements.hasNext()){
getItemInfo((ProjectItem)subElements.next());
}
}
}
}
interface Contact extends Serializable{
public static final String SPACE = " ";
public String getFirstName();
public String getLastName();
public String getTitle();
public String getOrganization();
public void setFirstName(String newFirstName);
public void setLastName(String newLastName);
public void setTitle(String newTitle);
public void setOrganization(String newOrganization);
}
class ContactImpl implements Contact{
private String firstName;
private String lastName;
private String title;
private String organization;
public ContactImpl(){}
public ContactImpl(String newFirstName, String newLastName,
String newTitle, String newOrganization){
firstName = newFirstName;
lastName = newLastName;
title = newTitle;
organization = newOrganization;
}
public String getFirstName(){ return firstName; }
public String getLastName(){ return lastName; }
public String getTitle(){ return title; }
public String getOrganization(){ return organization; }
public void setFirstName(String newFirstName){ firstName = newFirstName; }
public void setLastName(String newLastName){ lastName = newLastName; }
public void setTitle(String newTitle){ title = newTitle; }
public void setOrganization(String newOrganization){ organization = newOrganization; }
public String toString(){
return firstName + SPACE + lastName;
}
}
class Task implements ProjectItem{
private String name;
private ArrayList projectItems = new ArrayList();
private Contact owner;
private String details;
private ProjectItem parent;
private boolean primaryTask;
public Task(ProjectItem newParent){
this(newParent, "", "", null, false);
}
public Task(ProjectItem newParent, String newName,
String newDetails, Contact newOwner, boolean newPrimaryTask){
parent = newParent;
name = newName;
owner = newOwner;
details = newDetails;
primaryTask = newPrimaryTask;
}
public Contact getOwner(){
if (owner == null){
return parent.getOwner();
}
else{
return owner;
}
}
public String getDetails(){
if (primaryTask){
return details;
}
else{
return parent.getDetails() + EOL_STRING + "\t" + details;
}
}
public String getName(){ return name; }
public ArrayList getProjectItems(){ return projectItems; }
public ProjectItem getParent(){ return parent; }
public boolean isPrimaryTask(){ return primaryTask; }
public void setName(String newName){ name = newName; }
public void setOwner(Contact newOwner){ owner = newOwner; }
public void setParent(ProjectItem newParent){ parent = newParent; }
public void setPrimaryTask(boolean newPrimaryTask){ primaryTask = newPrimaryTask; }
public void setDetails(String newDetails){ details = newDetails; }
public void addProjectItem(ProjectItem element){
if (!projectItems.contains(element)){
projectItems.add(element);
}
}
public void removeProjectItem(ProjectItem element){
projectItems.remove(element);
}
public String toString(){
return name;
}
}
class DataCreator{
private static final String DEFAULT_FILE = "data.ser";
public static void main(String [] args){
String fileName;
if (args.length == 1){
fileName = args[0];
}
else{
fileName = DEFAULT_FILE;
}
serialize(fileName);
}
public static void serialize(String fileName){
try{
serializeToFile(createData(), fileName);
}
catch (IOException exc){
exc.printStackTrace();
}
}
private static Serializable createData(){
Contact contact1 = new ContactImpl("Dennis", "Moore", "Managing Director", "Highway Man, LTD");
Contact contact2 = new ContactImpl("Joseph", "Mongolfier", "High Flyer", "Lighter than Air Productions");
Contact contact3 = new ContactImpl("Erik", "Njoll", "Nomad without Portfolio", "Nordic Trek, Inc.");
Contact contact4 = new ContactImpl("Lemming", "", "Principal Investigator", "BDA");
Project project = new Project("IslandParadise", "Acquire a personal island paradise", contact2);
Task task1 = new Task(project, "Fortune", "Acquire a small fortune", contact4, true);
Task task2 = new Task(project, "Isle", "Locate an island for sale", null, true);
Task task3 = new Task(project, "Name", "Decide on a name for the island", contact3, false);
project.addProjectItem(task1);
project.addProjectItem(task2);
project.addProjectItem(task3);
Task task4 = new Task(task1, "Fortune1", "Use psychic hotline to predict winning lottery numbers", null, false);
Task task5 = new Task(task1, "Fortune2", "Invest winnings to ensure 50% annual interest", contact1, true);
Task task6 = new Task(task2, "Isle1", "Research whether climate is better in the Atlantic or Pacific", contact1, true);
Task task7 = new Task(task2, "Isle2", "Locate an island for auction on EBay", null, false);
Task task8 = new Task(task2, "Isle2a", "Negotiate for sale of the island", null, false);
Task task9 = new Task(task3, "Name1", "Research every possible name in the world", null, true);
Task task10 = new Task(task3, "Name2", "Eliminate any choices that are not coffee-related", contact4, false);
task1.addProjectItem(task4);
task1.addProjectItem(task5);
task2.addProjectItem(task6);
task2.addProjectItem(task7);
task2.addProjectItem(task8);
task3.addProjectItem(task9);
task3.addProjectItem(task10);
return project;
}
private static void serializeToFile(Serializable content, String fileName) throws IOException{
ObjectOutputStream serOut = new ObjectOutputStream(new FileOutputStream(fileName));
serOut.writeObject(content);
serOut.close();
}
}
interface ProjectItem extends Serializable{
public static final String EOL_STRING = System.getProperty("line.separator");
public ProjectItem getParent();
public Contact getOwner();
public String getDetails();
public ArrayList getProjectItems();
}
class Project implements ProjectItem{
private String name;
private Contact owner;
private String details;
private ArrayList projectItems = new ArrayList();
public Project(){ }
public Project(String newName, String newDetails, Contact newOwner){
name = newName;
owner = newOwner;
details = newDetails;
}
public String getName(){ return name; }
public String getDetails(){ return details; }
public Contact getOwner(){ return owner; }
public ProjectItem getParent(){ return null; }
public ArrayList getProjectItems(){ return projectItems; }
public void setName(String newName){ name = newName; }
public void setOwner(Contact newOwner){ owner = newOwner; }
public void setDetails(String newDetails){ details = newDetails; }
public void addProjectItem(ProjectItem element){
if (!projectItems.contains(element)){
projectItems.add(element);
}
}
public void removeProjectItem(ProjectItem element){
projectItems.remove(element);
}
public String toString(){
return name;
}
}
class DataRetriever{
public static Object deserializeData(String fileName){
Object returnValue = null;
try{
File inputFile = new File(fileName);
if (inputFile.exists() && inputFile.isFile()){
ObjectInputStream readIn = new ObjectInputStream(new FileInputStream(fileName));
returnValue = readIn.readObject();
readIn.close();
}
else {
System.err.println("Unable to locate the file " + fileName);
}
}
catch (ClassNotFoundException exc){
exc.printStackTrace();
}
catch (IOException exc){
exc.printStackTrace();
}
return returnValue;
}
}
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