95-733 Internet Technologies

1. 95-733 Internet Technologies • JAXB Java API for XML Binding • JavaMail

2. JAXB • The Java Architecture for XML Binding • Notes taken from the JAXB User’s Guide from Sun Microsystems

3. JAXB • Like SAX and DOM in that the application developer does not have to parse the XML • Unlike SAX and DOM it is tied to a particular document schema • Fast like SAX • In memory representation like DOM but without all the general tree manipulation facilities

4. JAXB • An XML Document is an instance of a schema • A Java object is an instance of a class • JAXB reads a schema and produces a class • Currently, the only schema supported is the Document Type Definition (DTD)

5. JAXB • Augments the standard DTD by providing type conversion <!ELEMENT notional (#PCDATA)> : : <notional>100.00</notional> • With JAXB we can make sure that Java converts this to a BigDecimal automatically

6. The Binding Schema • JAXB requires that we use a DTD AND a “Binding Schema” • The Binding Schema is an XML document JAXB .java file(s) DTD Binding Schema javac javac .class files

7. The Binding Schema • The binding schema contains instructions on how to bind a schema to classes. • It might say that : • this attribute (in the XML document) should be treated as an int • this element’s content is a BigDecimal • this element’s content is a String • this element should be treated as a class • and so on …

8. Running JAXB C:\McCarthy\www\95-733\examples\jaxb>java -jar D:\jaxb\jaxb-1.0-ea\lib\jaxb-xjc-1.0-ea.jar -help Usage: xjc <schema> [ <binding-schema> ] [ -d <directory> ] [ -roots <element-list> ] Options: -d <directory> Specify the destination directory for the Java output -roots <element-list> Designate one or more root elements (comma separated) -version Print the compiler's version number and exit -help Print this message and exit

9. Book.xml <?xml version="1.0" encoding="UTF-8" standalone="no"?> <!DOCTYPE book SYSTEM "book.dtd"> <book> <title>The Catcher in the Rye </title> <author>J.D. Salinger </author> <chapter>If you really want to hear about it... </chapter> </book>

10. Book.dtd <!ELEMENT book (title,author, chapter)> <!ELEMENT title (#PCDATA)> <!ELEMENT author (#PCDATA)> <!ELEMENT chapter (#PCDATA)>

11. A minimal binding schema Book.xjc <xml-java-binding-schema> <element name = "book" type = "class" root = "true" /> </xml-java-binding-schema>

12. Run JAXB C:\McCarthy\www\95-733\examples\jaxb>java -jar D:\jaxb\jaxb-1.0-ea\lib\jaxb-xjc-1.0-ea.jar book0.dtd book.xjc .\Book.java C:\McCarthy\www\95-733\examples\jaxb>

13. Resulting Book.java file import java.io.IOException; import java.io.InputStream; import javax.xml.bind.ConversionException; import javax.xml.bind.Dispatcher; import javax.xml.bind.InvalidAttributeException; import javax.xml.bind.LocalValidationException; import javax.xml.bind.MarshallableRootElement; import javax.xml.bind.Marshaller; import javax.xml.bind.MissingContentException; import javax.xml.bind.RootElement; import javax.xml.bind.StructureValidationException; import javax.xml.bind.UnmarshalException; import javax.xml.bind.Unmarshaller; import javax.xml.bind.Validator; import javax.xml.marshal.XMLScanner; import javax.xml.marshal.XMLWriter;

14. public class Book extends MarshallableRootElement implements RootElement { private String _Title; private String _Author; private String _Chapter; public String getTitle() { return _Title; } public void setTitle(String _Title) { this._Title = _Title; if (_Title == null) { invalidate(); } }

15. public String getAuthor() { return _Author; } public void setAuthor(String _Author) { this._Author = _Author; if (_Author == null) { invalidate(); } } public String getChapter() { return _Chapter; } public void setChapter(String _Chapter) { this._Chapter = _Chapter; if (_Chapter == null) { invalidate(); } }

16. public void validateThis() throws LocalValidationException { if (_Title == null) { throw new MissingContentException("title"); } if (_Author == null) { throw new MissingContentException("author"); } if (_Chapter == null) { throw new MissingContentException("chapter"); } } public void validate(Validator v) throws StructureValidationException { }

17. public void marshal(Marshaller m) throws IOException { XMLWriter w = m.writer(); w.start("book"); w.leaf("title", _Title.toString()); w.leaf("author", _Author.toString()); w.leaf("chapter", _Chapter.toString()); w.end("book"); } public void unmarshal(Unmarshaller u) throws UnmarshalException { XMLScanner xs = u.scanner(); Validator v = u.validator(); xs.takeStart("book"); while (xs.atAttribute()) { String an = xs.takeAttributeName(); throw new InvalidAttributeException(an); }

18. if (xs.atStart("title")) { xs.takeStart("title"); String s; if (xs.atChars(XMLScanner.WS_COLLAPSE)) { s = xs.takeChars(XMLScanner.WS_COLLAPSE); } else { s = ""; } try { _Title = String.valueOf(s); } catch (Exception x) { throw new ConversionException("title", x); } xs.takeEnd("title"); } if (xs.atStart("author")) { xs.takeStart("author"); String s; if (xs.atChars(XMLScanner.WS_COLLAPSE)) { s = xs.takeChars(XMLScanner.WS_COLLAPSE); } else { s = ""; }

19. try { _Author = String.valueOf(s); } catch (Exception x) { throw new ConversionException("author", x); } xs.takeEnd("author"); } if (xs.atStart("chapter")) { xs.takeStart("chapter"); String s; if (xs.atChars(XMLScanner.WS_COLLAPSE)) { s = xs.takeChars(XMLScanner.WS_COLLAPSE); } else { s = ""; } try { _Chapter = String.valueOf(s); } catch (Exception x) { throw new ConversionException("chapter", x); } xs.takeEnd("chapter"); }

20. xs.takeEnd("book"); } public static Book unmarshal(InputStream in) throws UnmarshalException { return unmarshal(XMLScanner.open(in)); } public static Book unmarshal(XMLScanner xs) throws UnmarshalException { return unmarshal(xs, newDispatcher()); } public static Book unmarshal(XMLScanner xs, Dispatcher d) throws UnmarshalException { return ((Book) d.unmarshal(xs, (Book.class))); }

21. public boolean equals(Object ob) { if (this == ob) { return true; } if (!(ob instanceof Book)) { return false; } Book tob = ((Book) ob); if (_Title!= null) { if (tob._Title == null) { return false; } if (!_Title.equals(tob._Title)) { return false; } } else { if (tob._Title!= null) { return false; } }

22. if (_Author!= null) { if (tob._Author == null) { return false; } if (!_Author.equals(tob._Author)) { return false; } } else { if (tob._Author!= null) { return false; } } if (_Chapter!= null) { if (tob._Chapter == null) { return false; } if (!_Chapter.equals(tob._Chapter)) { return false; }

23. } else { if (tob._Chapter!= null) { return false; } } return true; } public int hashCode() { int h = 0; h = ((127 *h)+((_Title!= null)?_Title.hashCode(): 0)); h = ((127 *h)+((_Author!= null)?_Author.hashCode(): 0)); h = ((127 *h)+((_Chapter!= null)?_Chapter.hashCode(): 0)); return h; }

24. public String toString() { StringBuffer sb = new StringBuffer("<<book"); if (_Title!= null) { sb.append(" title="); sb.append(_Title.toString()); } if (_Author!= null) { sb.append(" author="); sb.append(_Author.toString()); } if (_Chapter!= null) { sb.append(" chapter="); sb.append(_Chapter.toString()); } sb.append(">>"); return sb.toString(); }

25. public static Dispatcher newDispatcher() { Dispatcher d = new Dispatcher(); d.register("book", (Book.class)); d.freezeElementNameMap(); return d; } }

26. A Driver Program // demo JAXB import java.io.*; public class TestJaxb { public static void main(String args[]) throws java.io.FileNotFoundException, javax.xml.bind.UnmarshalException, java.io.IOException { DataInputStream in = new DataInputStream( new BufferedInputStream( new FileInputStream(args[0]))); DataOutputStream out = new DataOutputStream( new FileOutputStream(args[1]));

27. // read in the book Book catcher = Book.unmarshal(in); // change its title catcher.setTitle("Gone With The Wind"); // write out the book catcher.marshal(out); } }

28. Compile and Run C:\McCarthy\www\95-733\examples\jaxb>javac Book.java C:\McCarthy\www\95-733\examples\jaxb>javac TestJaxb.java C:\McCarthy\www\95-733\examples\jaxb>java TestJaxb book.xml out.xml

29. Out.xml <?xml version="1.0" encoding="UTF-8"?> <book> <title>Gone With The Wind</title> <author>J.D. Salinger</author> <chapter>If you really want to hear about it...</chapter></book>

30. Writing Simple Email Clients in Java • Email Using Sockets • Email using the JavaMail API

31. Email Using Sockets (Linden Chapter 17) // See page 571 of Linden's Just Java Fifth Edition import java.io.*; import java.net.*; public class SimpleEmailClient { public static void main(String args[]) throws IOException { Socket sock; DataInputStream dis; PrintStream ps;

32. // open a socket to an email server on port 25 sock = new Socket("cyrus.andrew.cmu.edu",25); dis = new DataInputStream(sock.getInputStream()); ps = new PrintStream(sock.getOutputStream()); // talk email ps.println("mail from: mm6@andrew.cmu.edu"); System.out.println(dis.readLine()); String Addressee = "mm6@andrew.cmu.edu"; ps.println("rcpt to: " + Addressee); System.out.println(dis.readLine());

33. ps.println("data"); System.out.println(dis.readLine()); ps.println("A message sent by a Java client using sockets"); ps.println("."); System.out.println(dis.readLine()); ps.flush(); sock.close(); } }

34. Output Echos from Cyrus D:\McCarthy\www\95-713\JavaMail>java SimpleEmailClient 220-mail-fe2.andrew.cmu.edu ESMTP Sendmail 8.12.3.Beta2/8.12.3. Beta2 220-Mis-identifing the sender of mail is an abuse of computing facilites. 220 ESMTP spoken here 250 2.1.0 mm6@andrew.cmu.edu... Sender ok

35. Using JavaMail // A simple example using JavaMail import java.io.*; import java.net.InetAddress; import java.util.Properties; import java.util.Date; import javax.mail.*; import javax.mail.internet.*; public class Mailer { String to, from, msg;

36. public Mailer(String to, String from, String msg) { this.to = to; this.from = from; this.msg = msg; } public void send() { Session s = createSession(); try { Message mess = createMessage(s, msg); Transport.send(mess); } catch(MessagingException e) { System.out.println("Messaging Exception: "+e); }

37. catch(Exception e ) { System.out.println("Exception thrown" + e); } } private Session createSession() { Properties p = System.getProperties(); p.setProperty("mail.transport.protocol", "smtp"); p.setProperty("mail.smtp.host","cyrus.andrew.cmu.edu"); Session sess = Session.getDefaultInstance(p); return sess; }

38. private Message createMessage(Session sess, String msg)throws MessagingException{ Message mess = new MimeMessage(sess); mess.setFrom(new InternetAddress(from)); mess.setRecipients(Message.RecipientType.TO, InternetAddress.parse(to, false)); mess.setSubject("Warning"); mess.setText(msg); mess.setSentDate(new Date()); return mess; }

39. public static void main(String a[]) { Mailer mailman = new Mailer("mm6@andrew.cmu.edu", "mccarthy@cs.pitt.edu", "It's hot"); mailman.send(); } }

40. JavaMail Installation Instructions Visit http://java.sun.com/products/javamail • Download the JavaMail API Implementation Version 1.3ea • Download the JavaBeans Activation Framework 1.0.2ea • Unzip both files. • Add the following files to your classpath: • mail.jar (JavaMail) • activation.jar (JAF file)