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package tutorial.message;
import net.jxta.document.AdvertisementFactory;
import net.jxta.document.MimeMediaType;
import net.jxta.document.StructuredDocumentFactory;
import net.jxta.document.XMLDocument;
import net.jxta.endpoint.ByteArrayMessageElement;
import net.jxta.endpoint.Message;
import net.jxta.endpoint.Message.ElementIterator;
import net.jxta.endpoint.MessageElement;
import net.jxta.endpoint.StringMessageElement;
import net.jxta.endpoint.TextDocumentMessageElement;
import net.jxta.endpoint.WireFormatMessage;
import net.jxta.endpoint.WireFormatMessageFactory;
import net.jxta.id.IDFactory;
import net.jxta.peergroup.PeerGroupID;
import net.jxta.pipe.PipeService;
import net.jxta.protocol.PipeAdvertisement;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.RandomAccessFile;
import java.util.zip.GZIPInputStream;
import java.util.zip.GZIPOutputStream;
/**
* A simple and re-usable example of manipulating JXATA Messages. Included in
* this tutorial are:
* <p/>
* <ul>
* <li>Adding and reading {@code String}, {@code int} and {@code long} with Message elements.</li>
* <li>Adding and reading Java {@code Object} with Message Elements.
* <li>Adding and reading byte arrays with Message Elements.</li>
* <li>Adding and reading JXTA Advertisements with Message Elements.</li>
* <li>Compressing message element content with gzip.</li>
* </ul>
*/
public class MessageTutorial {
private final static MimeMediaType GZIP_MEDIA_TYPE = new MimeMediaType("application/gzip").intern();
/**
* Adds a String to a Message as a StringMessageElement
*
* @param message The message to add to
* @param nameSpace The namespace of the element to add. a null value assumes default namespace.
* @param elemName Name of the Element.
* @param string The string to add
*/
public static void addStringToMessage(Message message, String nameSpace, String elemName, String string) {
message.addMessageElement(nameSpace, new StringMessageElement(elemName, string, null));
}
/**
* Adds a long to a message
*
* @param message The message to add to
* @param nameSpace The namespace of the element to add. a null value assumes default namespace.
* @param elemName Name of the Element.
* @param data The feature to be added to the LongToMessage attribute
*/
public static void addLongToMessage(Message message, String nameSpace, String elemName, long data) {
message.addMessageElement(nameSpace, new StringMessageElement(elemName, Long.toString(data), null));
}
/**
* Adds a int to a message
*
* @param message The message to add to
* @param nameSpace The namespace of the element to add. a null value assumes default namespace.
* @param elemName Name of the Element.
* @param data The feature to be added to the IntegerToMessage attribute
*/
public static void addIntegerToMessage(Message message, String nameSpace, String elemName, int data) {
message.addMessageElement(nameSpace, new StringMessageElement(elemName, Integer.toString(data), null));
}
/**
* Adds an byte array to a message
*
* @param message The message to add to
* @param nameSpace The namespace of the element to add. a null value assumes default namespace.
* @param elemName Name of the Element.
* @param data the byte array
* @param compress indicates whether to use GZIP compression
* @throws IOException if an io error occurs
*/
public static void addByteArrayToMessage(Message message, String nameSpace, String elemName, byte[] data, boolean compress) throws IOException {
byte[] buffer = data;
MimeMediaType mimeType = MimeMediaType.AOS;
if (compress) {
ByteArrayOutputStream outStream = new ByteArrayOutputStream();
GZIPOutputStream gos = new GZIPOutputStream(outStream);
gos.write(data, 0, data.length);
gos.finish();
gos.close();
buffer = outStream.toByteArray();
mimeType = GZIP_MEDIA_TYPE;
}
message.addMessageElement(nameSpace, new ByteArrayMessageElement(elemName, mimeType, buffer, null));
}
/**
* Adds an Object to message within the specified name space and with the specified element name
* @param message the message to add the object to
* @param nameSpace the name space to add the object under
* @param elemName the given element name
* @param object the object
* @throws IOException if an io error occurs
*/
public static void addObjectToMessage(Message message, String nameSpace, String elemName, Object object) throws IOException {
ByteArrayOutputStream bos = new ByteArrayOutputStream();
ObjectOutputStream oos = new ObjectOutputStream(bos);
oos.writeObject(object);
oos.close();
bos.close();
addByteArrayToMessage(message, nameSpace, elemName, bos.toByteArray(), false);
}
/**
* Returns a String from a message
*
* @param message The message to retrieve from
* @param nameSpace The namespace of the element to get.
* @param elemName Name of the Element.
* @return The string value or {@code null} if there was no element matching the specified name.
*/
public static String getStringFromMessage(Message message, String nameSpace, String elemName) {
MessageElement me = message.getMessageElement(nameSpace, elemName);
if (null != me) {
return me.toString();
} else {
return null;
}
}
/**
* Returns an long from a message
*
* @param message The message to retrieve from
* @param nameSpace The namespace of the element to get.
* @param elemName Name of the Element.
* @return The long value
* @throws NumberFormatException If the String does not contain a parsable int.
*/
public static long getLongFromMessage(Message message, String nameSpace, String elemName) throws NumberFormatException {
String longStr = getStringFromMessage(message, nameSpace, elemName);
if (null != longStr) {
return Long.parseLong(longStr);
} else {
throw new NumberFormatException("No such Message Element.");
}
}
/**
* Returns an int from a message
*
* @param message The message to retrieve from
* @param nameSpace The namespace of the element to get.
* @param elemName Name of the Element.
* @return The int value
* @throws NumberFormatException If the String does not contain a parsable long.
*/
public static int getIntegerFromMessage(Message message, String nameSpace, String elemName) throws NumberFormatException {
String intStr = getStringFromMessage(message, nameSpace, elemName);
if (null != intStr) {
return Integer.parseInt(intStr);
} else {
throw new NumberFormatException("No such Message Element.");
}
}
/**
* Returns an InputStream for a byte array
*
* @param message The message to retrieve from
* @param nameSpace The namespace of the element to get.
* @param elemName Name of the Element.
* @return The {@code InputStream} or {@code null} if the message has no such element, String elemName) throws IOException {
* @throws IOException if an io error occurs
*/
public static InputStream getInputStreamFromMessage(Message message, String nameSpace, String elemName) throws IOException {
InputStream result = null;
MessageElement element = message.getMessageElement(nameSpace, elemName);
if (null == element) {
return null;
}
if (element.getMimeType().equals(GZIP_MEDIA_TYPE)) {
result = new GZIPInputStream(element.getStream());
} else if (element.getMimeType().equals(MimeMediaType.AOS)) {
result = element.getStream();
}
return result;
}
/**
* Reads a single Java Object from a Message.
*
* @param message The message containing the object.
* @param nameSpace The name space of the element containing the object.
* @param elemName The name of the element containing the object.
* @return The Object or {@code null} if the Message contained no such element.
* @throws IOException if an io error occurs
* @throws ClassNotFoundException if an object could not constructed from the message element
*/
public static Object getObjectFromMessage(Message message, String nameSpace, String elemName) throws IOException, ClassNotFoundException {
InputStream is = getInputStreamFromMessage(message, nameSpace, elemName);
if (null == is) {
return null;
}
ObjectInputStream ois = new ObjectInputStream(is);
return ois.readObject();
}
/**
* Prints message element names and content and some stats
*
* @param msg message to print
* @param verbose indicates whether to print elment content
*/
public static void printMessageStats(Message msg, boolean verbose) {
try {
System.out.println("------------------Begin Message---------------------");
WireFormatMessage serialed = WireFormatMessageFactory.toWire(msg, new MimeMediaType("application/x-jxta-msg"), null);
System.out.println("Message Size :" + serialed.getByteLength());
ElementIterator it = msg.getMessageElements();
while (it.hasNext()) {
MessageElement el = it.next();
System.out.println("Element : " + it.getNamespace() + " :: " + el.getElementName());
if (verbose) {
System.out.println("[" + el + "]");
}
}
System.out.println("-------------------End Message----------------------");
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* Illustrates adding and retrieving a String to and from a Message
*/
public static void stringExample() {
Message message = new Message();
addStringToMessage(message, "TutorialNameSpace", "String Test", "This is a test");
printMessageStats(message, true);
System.out.println("String Value :" + getStringFromMessage(message, "TutorialNameSpace", "String Test"));
}
/**
* Illustrates adding and retrieving a long to and from a Message
*/
public static void longExample() {
Message message = new Message();
addLongToMessage(message, "TutorialNameSpace", "long test", Long.MAX_VALUE);
printMessageStats(message, true);
System.out.println("long Value :" + getLongFromMessage(message, "TutorialNameSpace", "long test"));
}
/**
* Illustrates adding and retrieving an integer to and from a Message
*/
public static void intExample() {
Message message = new Message();
addIntegerToMessage(message, "TutorialNameSpace", "int test", Integer.MAX_VALUE);
printMessageStats(message, true);
System.out.println("int Value :" + getIntegerFromMessage(message, "TutorialNameSpace", "int test"));
}
/**
* Illustrates adding and retrieving byte-array to and from a Message
*/
public static void byteArrayExample() {
Message message = new Message();
try {
File file = new File("message.tst");
file.createNewFile();
RandomAccessFile raf = new RandomAccessFile(file, "rw");
raf.setLength(1024 * 4);
int size = 4096;
byte[] buf = new byte[size];
raf.read(buf, 0, size);
addByteArrayToMessage(message, "TutorialNameSpace", "byte test", buf, true);
printMessageStats(message, true);
InputStream is = getInputStreamFromMessage(message, "TutorialNameSpace", "byte test");
int count = 0;
while (is.read() != -1) {
count++;
}
System.out.println("Read " + count + " byte back");
} catch (IOException io) {
io.printStackTrace();
}
}
/**
* Illustrates adding and retrieving advertisements to and from a Message
*/
public static void xmlDocumentExample() {
Message message = new Message();
PipeAdvertisement pipeAdv = (PipeAdvertisement) AdvertisementFactory.newAdvertisement(PipeAdvertisement.getAdvertisementType());
pipeAdv.setPipeID(IDFactory.newPipeID(PeerGroupID.defaultNetPeerGroupID));
pipeAdv.setType(PipeService.UnicastType);
message.addMessageElement("MESSAGETUT",
new TextDocumentMessageElement("MESSAGETUT", (XMLDocument) pipeAdv.getDocument(MimeMediaType.XMLUTF8), null));
MessageElement msgElement = message.getMessageElement("MESSAGETUT", "MESSAGETUT");
try {
XMLDocument asDoc = (XMLDocument) StructuredDocumentFactory.newStructuredDocument(msgElement.getMimeType(),
msgElement.getStream());
PipeAdvertisement newPipeAdv = (PipeAdvertisement) AdvertisementFactory.newAdvertisement(asDoc);
System.out.println(newPipeAdv.toString());
} catch (IOException e) {
// This is thrown if the message element could not be read.
e.printStackTrace();
} catch (IllegalArgumentException e) {
// This is thrown if the document or advertisement is invalid (illegal values, missing tags, etc.)
e.printStackTrace();
}
}
/**
* Main method
*
* @param args command line arguments. None defined
*/
public static void main(String args[]) {
stringExample();
longExample();
intExample();
byteArrayExample();
xmlDocumentExample();
}
}