studentcmpclient.java

J2EE开发与Weblogic一书中的源代码

package com.learnweblogic.examples.ch9.cmp;


import java.rmi.RemoteException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.Properties;

import javax.ejb.CreateException;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.rmi.PortableRemoteObject;

import com.learnweblogic.examples.BaseClient;


public final class StudentCMPClient extends BaseClient {

  private final static boolean debug   = true;
  private final static boolean verbose = true;

  private StudentHome studentHome;
  private BookHome bookHome;
  private TeacherHome teacherHome;
  private LockerHome lockerHome;

  private int studentCount;
  private int booksPerStudent;

  private Context ctx;

  public StudentCMPClient(String [] argv)
    throws NamingException
  {
    super(argv);

    ctx = getInitialContext();

    studentHome = 
      (StudentHome) narrow(ctx.lookup("StudentCMPEJB"), StudentHome.class);

    bookHome = (BookHome) narrow(ctx.lookup("BookCMPEJB"), BookHome.class);
    teacherHome = 
      (TeacherHome) narrow(ctx.lookup("TeacherCMPEJB"), TeacherHome.class);
    
    lockerHome = (LockerHome) narrow(ctx.lookup("LockerCMPEJB"),
      LockerHome.class);

  }

  ///////////////////////////////////////////////////////////////////////
  // Utility code

  private void deleteOldLockers(int N) {
    
    for (int i=0; i<N; i++) {
      try {
        lockerHome.remove(new Integer(i));
      } catch (Exception ignore) {}
    }
  }

  private void deleteOldStudents(int N) {
    
    for (int i=0; i<N; i++) {
      try {
        studentHome.remove(new Integer(i));
      } catch (Exception ignore) {}
    }
  }

  private void deleteOldTeachers(int N) {
    
    for (int i=0; i<N; i++) {
      try {
        teacherHome.remove(new Integer(i));
      } catch (Exception ignore) {}
    }
  }

  private void deleteOldBooks(int N, int numCopies) {
    
    BookPK pk;

    for (int i=0; i<N; i++) {
      
      for (int j=0; j<numCopies; j++) {
        try {
          pk = new BookPK(String.valueOf(i), j); 
          bookHome.remove(pk);
        } catch (Exception ignore) {}
      }
    }
  }

  private void pause() {
    try {
      Thread.sleep(10000);
    } catch (Exception e) {}
  }

  ///////////////////////////////////////////////////////////////////////
  // Create Beans For CMP Examples


  private Student [] createStudents() 
    throws CreateException, RemoteException
  {
    System.err.println("Creating Student CMP Entity beans.....");

    String [] names = { "Andrew", "Evelyn", "Joe", "Matt", "Jim" };

    deleteOldStudents(names.length);

    Student [] students = new Student[names.length];

    for (int i=0; i<names.length; i++) {
      
      // create stuydents in the 10th grade
      students[i] = studentHome.create(names[i], i, 10);

    }

    return students;
  }

  private Locker [] createLockers(int N) 
    throws CreateException, RemoteException
  {
    System.err.println("Creating Locker CMP Entity beans.....");

    deleteOldLockers(N);

    Locker [] lockers = new Locker[N];

    for (int i=0; i<N; i++) {
      
      // create stuydents in the 10th grade
      lockers[i] = lockerHome.create(new Integer(i));

    }

    return lockers;
  }

  private Teacher [] createTeachers() 
    throws CreateException, RemoteException
  {
    System.err.println("Creating Teacher CMP Entity beans.....");

    String [] names = { "George", "John", "Thomas", "James"};

    deleteOldTeachers(names.length);

    Teacher [] teachers = new Teacher[names.length];

    for (int i=0; i<names.length; i++) {
      
      // create our teachers
      teachers[i] = teacherHome.create(names[i], new Integer(i));

    }

    return teachers;
  }

  private Book [] createBooks(int numCopies) 
    throws CreateException, RemoteException
  {
    System.err.println("Creating Book CMP Entity beans.....");

    String [] titles = {"Hamlet", "Moby Dick", "The Stranger"};
    String [] authors = {"Shakespeare", "Melville", "Camus"};

    deleteOldBooks(titles.length, numCopies);

    Book [] books = new Book[titles.length * numCopies];

    for (int i=0; i<titles.length; i++) {
      
      for (int j=0; j<numCopies; j++) {

        books[i*numCopies+j] = 
          bookHome.create(authors[i], titles[i], String.valueOf(i), j);
      }
    }

    return books;
  }


  private void runClient() 
    throws Exception
  {

    System.err.println("");
    System.err.println("Running EJB 2.0 CMP Example:");
    System.err.println("");


    Student [] students = null;
    Locker  [] lockers  = null;
    Book    [] books    = null;
    Teacher [] teachers = null;


    try {
      students = createStudents();
    
      // create 1 locker for each student
      lockers  = createLockers(students.length);

      // create 1 book for each student;
      books    = createBooks(students.length);

      teachers = createTeachers();

    } catch (Exception e) {
      System.err.println("Unable to create the example beans.");
      System.err.println("The error was: ");
      e.printStackTrace();
      throw e;
    }


    System.err.println("");
    System.err.println("Updating relationships....");

    System.err.println("");


    // Assign each Student a Locker

    System.err.println("Assigning each Student to a Locker.");

    for (int i=0; i<students.length; i++) {
      students[i].assignLocker(lockers[i]);
    }

    // Assign the books out to the students

    System.err.println("Assigning books to each Student.");

    for (int i=0; i<books.length; i++) {
      
      students[i % students.length].assignBook(books[i]);
    }
    

    // Assign students to teachers
    // Student 0 gets student 0
    // Student 1 gets students 0,1 etc.

    System.err.println("Assigning Students to Teachers.");

    for (int i=0; i<teachers.length; i++) {
      
      for (int j=0; j<i; j++) {
        students[j].assignTeacher(teachers[i]);
      }
    }

    System.err.println("");
    System.err.println("Finding All the Students in grade 10.");
    System.err.println("");

    try {
      Collection c = studentHome.findStudentsInGrade(10);

      if (c.isEmpty()) {
        System.err.println("No Students were found in grade 10.");
      } else {

        Iterator it = c.iterator();

        while (it.hasNext()) {
          Student s = (Student) narrow(it.next(), Student.class);

          System.err.println("Found student named: "+s.getName()+
            " in grade 10.");
        }

        System.err.println("");

      }
    } catch (Exception e) {
      System.err.println("Unable to find students in grade 10.");
      System.err.println("The error was: ");
      e.printStackTrace();
      throw e;
    }

    System.err.println("");
    System.err.println("Finding All the Students with a Locker.");
    System.err.println("");


    try {
      Collection c = studentHome.findStudentsWithALocker();

      if (c.isEmpty()) {
        System.err.println("No Students were found with Lockers.");
      } else {

        Iterator it = c.iterator();

        while (it.hasNext()) {
          Student s = (Student) narrow(it.next(), Student.class);

          System.err.println("Found student named: "+s.getName()+
            " with a Locker.");
        }

        System.err.println("");

      }
    } catch (Exception e) {
      System.err.println("Unable to find students WITH Lockers.");
      System.err.println("The error was: ");
      e.printStackTrace();
      throw e;
    }

    System.err.println("");
    System.err.println("Finding All the Students with a Locker.");
    System.err.println("");


    try {
      Collection c = studentHome.findStudentsWithBooksTitled("Hamlet");

      if (c.isEmpty()) {
        System.err.println("No Students were found with books named Hamlet.");
      } else {

        Iterator it = c.iterator();

        while (it.hasNext()) {
          Student s = (Student) narrow(it.next(), Student.class);

          System.err.println("Found student named: "+s.getName()+
            " with a book named Hamlet.");
        }

        System.err.println("");

      }
    } catch (Exception e) {
      System.err.println("Unable to find students WITH books named Hamlet.");
      System.err.println("The error was: ");
      e.printStackTrace();
      throw e;
    }



  }
      

  public static void main(String[] argv) 
    throws Exception
  {
    StudentCMPClient sc = new StudentCMPClient(argv);

    sc.runClient();

  }
}