"A Beginner's Guide to Writing Applications for the MID Profile"
Vol. 6, Issue 9, p. 114

	


Listing 1 PhoneEJB.java

import java.io.*;
import java.g.*;
import javax.ejb.*;


public class PhoneEJB implements SessionBean {


  String user;
  Map phoneBook;


  public void ejbCreate(String user) throws CreateException {


    DataInputStream dis = null;


    try {
      if (user == null) {
        throw new CreateException("Null user not allowed.");
      }
      else {
        this.user = user;
      }


      phoneBook = new HashMap();


      File f = new File(user + ".dat");
      if (f.exists() && f.canRead()) {
        dis = new DataInputStream(new FileInputStream(f));


        while (dis.available() > 0) {
          String name = dis.readUTF();
          String phone = dis.readUTF();


          phoneBook.put(name,phone);
        }
      }
    }
    catch (IOException e) {
      throw new CreateException("unable to read data file : " + e.getMessage());
    }
    finally {
      if (dis != null) {
        try { dis.close(); } catch (Exception e) { }
        dis = null;
      }
    } 


  }


  public void ejbRemove() {
    DataOutputStream dos = null;
    try {
      dos = new DataOutputStream(new FileOutputStream(user + ".dat"));


      Iterator iter = phoneBook.keySet().iterator();
      String name, phone;
      while (iter.hasNext()) {
        name = (String)iter.next();
        phone = (String)phoneBook.get(name);


        dos.writeUTF(name);
        dos.writeUTF(phone);
      }


    }
    catch (IOException e) {
      e.printStackTrace();
    }
    finally {
      if (dos != null) {
        try { dos.close(); } catch (Exception e) { }
        dos = null;
      }
    }


  }



  public void add(String name, String phone) {
    phoneBook.put(name, phone);
  }


  public void remove(String name) {
    if (phoneBook.containsKey(name)) {
      phoneBook.remove(name);
    }
  }


  public Map getPhoneBook() {
    return phoneBook;
  }


  public PhoneEJB() {}
  public void ejbActivate() {}
  public void ejbPassivate() {}
  public void setSessionContext(SessionContext sc) {}


}




Listing 2 : TestPhoneServlet.java (part of doGet method)

1.    Context initial = new InitialContext();
2.    Object objref   = initial.lookup("MyPhoneEJB");
3.
4.    PhoneHome home  = (PhoneHome)PortableRemoteObject.narrow(objref, PhoneHome.class);
5.
6.    phoneejb  = home.create("test");
7.
8.    action    = request.getParameter("action");
9.    if (action == null || action.equals("")) {
10.
11.     Map phoneBook   = phoneejb.getPhoneBook();
12.
13.     Iterator iter = phoneBook.keySet().iterator();
14.     while (iter.hasNext()) {
15.       String name = (String)iter.next();
16.       String phone = (String)phoneBook.get(name);
17.
18.       out.println(name + phone);
19.     }
20.
21.   }
22.   else if (action.equals("add")) {
23.     String name = request.getParameter("name");
24.     String phone = request.getParameter("phone");
25.     if (name == null || phone == null) {
26.       throw new Exception("missing name and/or phone");
27.     }
28.
29.     phoneejb.add(name,phone);
30.
31.     out.println("");
32.   }
33.   else if (action.equals("remove")) {
34.     String name = request.getParameter("name");
35.     if (name == null) {
36.       throw new Exception("missing name");
37.     }
38.
39.     phoneejb.remove(name);
40.
41.     out.println("");
42.   }
43.   else {
44.     out.println("%ERROR : unrecognized command");
45.   }



Listing 3 : PhoneBook.java (initRecordStore method)

private final void initRecordStore() throws Exception {
    store = RecordStore.openRecordStore("PhoneBook",true);


    String s = sendToServer("http://localhost:8080/servlet/TestPhoneServlet");


    if (s != null && !s.equals("") && !s.startsWith("%ERROR")) {
      recordEnum = store.enumerateRecords(null, pbcomp, false);
      while (recordEnum.hasNextElement()) {
        int id = recordEnum.nextRecordId();


        store.deleteRecord(id);
      }


      String line = "";
      for (int i = 0; i < s.length(); i++) {
        if (s.charAt(i) == '\n') {
          if (line.length() > 0) {
save(line.substring(0,MAX_NAME_LENGTH),line.substring(MAX_NAME_LENGTH), false);
          }


          line = "";
        }
        else {
          line += s.charAt(i);
        }
      }
      if (line.length() > 0) {
save(line.substring(0,MAX_NAME_LENGTH),line.substring(MAX_NAME_LENGTH), false);
      }
    }


    recordEnum = store.enumerateRecords(null, pbcomp, false);
  }




Listing 4 : PhoneBook.java (save and erase methods)

/**
  * save a name and phone number to the record store
  */
  private final void save(String name, String phone, boolean sendToServer) throws Exception {
    if (isEmpty(name)) {
      throw new Exception("No name entered");
    }
    else if (isEmpty(phone)) {
      throw new Exception("No phone entered");
    }
    else if (name.length() > MAX_NAME_LENGTH) {
      throw new Exception("Name too long, max=" + MAX_NAME_LENGTH);
    }
    else {
      byte n[] = rpad(name,10,' ').getBytes();
      byte p[] = rpad(phone,0,' ').getBytes();
      byte rec[] = new byte[n.length + p.length];
      System.arraycopy(n,0,rec,0,n.length);
      System.arraycopy(p,0,rec,n.length,p.length);


      if (sendToServer) {
        String send = "http://localhost:8080/servlet/TestPhoneServlet?action=add&name=" + rpad(replace(name,' ','+'),10,'+') + "&phone=" + phone;
        String rtn = sendToServer(send);


        if (rtn != null && !rtn.trim().equals("")) {
          throw new Exception("Server error : "+ rtn);
        }
      }


      store.addRecord(rec,0,rec.length);



      n = null;
      p = null;
      rec = null;
    }
  }


 /**
  * erase the current record
  */
  private final void erase(boolean sendToServer) throws Exception {
    if (currentRecordID < 0) {
      return;
    }


    try {
      if (sendToServer) {
        String send = "http://localhost:8080/servlet/TestPhoneServlet?action=remove&name=" + rpad(replace(list.getName(),' ','+'),10,'+');
        String rtn = sendToServer(send);


        if (rtn != null && !rtn.trim().equals("")) {
          throw new Exception("Server error : "+ rtn);
        }
      }



      store.deleteRecord(currentRecordID);
      if (store.getNumRecords() < 1) {
        currentRecordID = -1;
        set(null);
      }
    }
    catch (InvalidRecordIDException irie) {
      throw new Exception("Invalid record");
    }
    catch (Exception e) {
      throw new Exception("Unhandled.");
    }


  }