Chain模式例子

  
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;   
    }   
}