Develop Reference

Why are threads using the same variable value? RxJava Mqtt

I'm using rxmqtt (which uses rxjava and paho) to communicate whith a mqtt broker. I'm using javax to accept rest requests and publish some content to the broker and wait for a response. The code below works fine if I make one request at a time, but if I have more than one concurrent requests it only returns a response for the last one and the others fall into the timeout exception.
The mqttConn.getMqttMessages() returns a flowable which is already subscribed to all topics i need:
public Flowable<MqttMessage> getMqttMessages() {
return this.obsClient.subscribe("pahoRx/fa/#", 1);
}
and MqttConnection is a singleton because i only want one single connection to broker and all the publishes are done in this connection
I've noticed that my queryParam id is different in each thread execution of the web service request (expected behavior), but when it enters the subscription part of the code it only considers the last id value and does not pass my validation in the takeUntil method:
mqttConn.getMqttMessages().timeout(20, TimeUnit.SECONDS).takeUntil(msgRcv -> {
System.out.println("received: " + new String(msgRcv.getPayload()) + " ID: " + id);
return id.equals(new String(msgRcv.getPayload()));
}).blockingSubscribe(msgRcv -> {
final byte[] body = msgRcv.getPayload();
System.out.println(new String(body)); //printing... but not sending the reponse
response.set("Message Receiced: " + new String(msgRcv.getPayload()));
return;
}, e -> {
if (e instanceof TimeoutException) {
response.set("Timeout Occured");
} else {
response.set("Some kind of error occured " + e.getLocalizedMessage());
}
});
The thing is, why is it only considering the last id received when each request should have its own independent thread? I've tried getting mqttConn.getMqttConnection() as a ThreadLocal object... doesn't fix.
Full WS code:
#Path("/test")
#GET
public String test(#QueryParam("id") String id) throws InterruptedException, MqttException {
String funcExec = "pahoRx/fe/";
String content = "unlock with single connection to broker";
int qos = 1;
AtomicReference<String> response = new AtomicReference<String>();
response.set("Initial Value");
MqttConnection mqttConn = MqttConnection.getMqttConnection();
ObservableMqttClient obsClient = mqttConn.getBrokerClient();
MqttMessage msg = MqttMessage.create(78, content.getBytes(), qos, false);
String topicPub = funcExec + id;
obsClient.publish(topicPub, msg).subscribe(t -> {
System.out.println("Message Published");
}, e -> {
System.out.println("Failed to publish message: " + e.getLocalizedMessage());
});
mqttConn.getMqttMessages().timeout(20, TimeUnit.SECONDS).takeUntil(msgRcv -> {
System.out.println("received: " + new String(msgRcv.getPayload()) + " ID: " + id);
return id.equals(new String(msgRcv.getPayload()));
}).blockingSubscribe(msgRcv -> {
final byte[] body = msgRcv.getPayload();
System.out.println(new String(body)); //printing... but not sending the reponse
response.set("Message Receiced: " + new String(msgRcv.getPayload()));
return;
}, e -> {
if (e instanceof TimeoutException) {
response.set("Timeout Occured");
} else {
response.set("Some kind of error occured " + e.getLocalizedMessage());
}
});
return response.get();
}
I hope the explanation is clear enough!
Ty in advance

Call a java Rest webservice on email event

I have a webservice x exposed.If I get a mail in my email containing attachment I want to call
this webservice.I am not asking for code.I am asking your suggestion in high level how this can be done?

You need REST. So - you cant use org.apache.http.client library. (Other way, if you'll have web service you can use wsimport to create WebService java-client.)
Use javax.mail library to open mailbox and iterate letters.
Process letters. Mark or delete processed letters.
Add crontab/sheduler task to run your app. (As for me, It's better, than create a thread app). Dont forget to use run-one option to prevent double execution.
Here some code example that reads "*.xls" files from mailbox messages:
public void processEmail() throws MessagingException {
Store emailStore = null;
Folder emailFolder = null;
try {
// connecting
Properties properties = new Properties();
properties.setProperty("mail.store.protocol", "imaps");
Session emailSession = Session.getDefaultInstance(properties);
Main.getLog().debug("CONNECT TO : " + config.mailServer + " ["
+ config.mailUser + "] DEBUG: "+config.debug);
// check mailbox
emailStore = emailSession.getStore("imaps");
emailStore.connect(config.mailServer, config.mailUser,
config.mailPassword);
Main.getLog().debug("CONNECT DONE");
emailFolder = emailStore.getFolder("INBOX");
emailFolder.open(Folder.READ_WRITE);
Message[] messages = emailFolder.getMessages();
Main.getLog().debug("RECEIVED " + messages.length + " MESSAGSES");
// for each letter
for (Message message : messages) {
try {
Main.getLog().debug("\nPROCESS LETTER : "
+ message.getSubject());
if (message.getFlags().contains(Flags.Flag.DELETED)) {
continue; // don't process such letters
}
if (message.getFlags().contains(Flags.Flag.SEEN)) {
continue; // don't process such letters
}
//
Map<String, String> parseResult = new HashMap<String, String>();
String auditId = "";
// get file
if (message.getContent() instanceof Multipart) {
Multipart multipart = (Multipart) message.getContent();
for (int i = 0; i < multipart.getCount(); i++) {
BodyPart bodyPart = multipart.getBodyPart(i);
if (!Part.ATTACHMENT.equalsIgnoreCase(bodyPart
.getDisposition())) {
continue;
}
// Process file
if (bodyPart.getFileName().contains(".xls")) {
auditId = maintainExcelFile(bodyPart.getInputStream());
}
}
} else if (message.getContent() instanceof BASE64DecoderStream) {
// Process file
if (message.getFileName().contains(".xls")) {
auditId = maintainExcelFile(((BASE64DecoderStream) message
.getContent()));
}
}
if (!config.debug && auditId!=null && !auditId.equals("")) {
message.setFlag(Flags.Flag.SEEN, true);
}
if (!config.debug) {
sendAcceptMail(message, auditId);
}
} catch (Exception e) {
// Process errors
if (!config.debug) {
message.setFlag(Flags.Flag.SEEN, true);
sendErrorMail(message, e);
}
Main.getLog().error(e.getMessage(), e);
throw new Exception(e);
}
}
} catch (Exception e) {
Main.getLog().error(e.getMessage(), e);
} finally {
emailFolder.close(true);
emailStore.close();
}
}

Sporadically getting javax.mail.FolderClosedException while reading gmail emails using javamail

I am trying to read javamail inbox and perform search. For this, I am fetching the latest 100 messages and then I am iterating through each to see if they have the sender for whom I am searching for. If its matching, I get its content via getContent().
Here is my javamail code snippet:
try {
Properties properties = new Properties();
properties.setProperty("mail.store.protocol", "imap");
properties.put("mail.imaps.starttls.enable", "true");
properties.put("mail.imap.socketFactory.port", "587");
System.setProperty("javax.net.debug", "ssl");
System.out.println("prop " + properties.getProperty("mail.smtp.port"));
Session session = Session.getDefaultInstance(properties, null);
// session.setDebug(true);
Store store = null;
store = session.getStore("imaps");
store.connect("imap.gmail.com", username, password);
Folder inbox;
inbox = store.getFolder("Inbox");
/* Others GMail folders :
* [Gmail]/All Mail This folder contains all of your Gmail messages.
* [Gmail]/Drafts Your drafts.
* [Gmail]/Sent Mail Messages you sent to other people.
* [Gmail]/Spam Messages marked as spam.
* [Gmail]/Starred Starred messages.
* [Gmail]/Trash Messages deleted from Gmail.
*/
inbox.open(Folder.READ_WRITE);
Message msgs[] = inbox.getMessages(inbox.getMessageCount() - lastHistory, inbox.getMessageCount());
System.out.println("MSgs.length " + msgs.length);
ArrayList<Message> aList = new ArrayList<Message>();
appendTextToConsole("Searching for appropriate messages!!");
for (int ii = msgs.length - 1; ii >= 0; ii--) {
Message msg = msgs[ii];
Address[] in = msg.getFrom();
String sender = InternetAddress.toString(in);
System.out.println((++index) + "Sender: " + sender);
boolean read = msg.isSet(Flags.Flag.SEEN);
if (sender.contains(googleId) && !read) {
//This line below gives FolderClosedException sporadically
Object content = msg.getContent();
if (content instanceof Multipart) {
Multipart mp = (Multipart) content;
for (int i = 0; i < mp.getCount(); i++) {
BodyPart bp = mp.getBodyPart(i);
if (Pattern
.compile(Pattern.quote("text/html"),
Pattern.CASE_INSENSITIVE)
.matcher(bp.getContentType()).find()) {
// found html part
String html = (String) bp.getContent();
Element element = Jsoup.parse(html);
List<Element> anchors = element.getElementsByTag("a");
for (Element e : anchors) {
if (e.attr("href").startsWith("https://www.google.com/url?rct=j&sa=t&url=")
&& !e.attr("style").equalsIgnoreCase("text-decoration:none")) {
String url = e.attr("href");
String title = e.text();
String agency = e.parent().parent().child(1).child(0).child(0).text();
String message = e.parent().parent().child(1).child(0).child(1).text();
String flagUrl = e.parent().parent().child(1).child(1).child(0).child(0).child(3).child(0).attr("href");
System.out.println("URL: " + url);
System.out.println("Title: " + title);
System.out.println("agency: " + agency);
System.out.println("Message: " + message);
System.out.println("flagURL: " + flagUrl);
AbstractMessage ams = new AbstractMessage(url, title, agency, message, flagUrl);
aMsgs.add(ams);
}
}
//System.out.println((String) bp.getContent());
} else {
// some other bodypart...
}
}
try {
inbox.close(true);
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
appendTextToConsole("Done searching for appropriate messages!!");
} catch (Exception mex) {
appendTextToConsole(mex.getMessage());
mex.printStackTrace();
}
But the most irritating thing is that after fetching a few messages, sporadically a javax.mail.FolderClosedException is thrown due to unknown reasons. Now my question is that how do I deal with this scenario? And how do ideal mail clients made using javamail deal with it?

Turn on session debugging and you might get more clues as to what's going on.
Note that the server will close the connection if you're not using it.
And of course all sorts of network failures are possible.

Blackberry Connection Nightmare

I'm busy writing a Program that Transmits GPS Coordinates to a Server from a mobile phone where the coordinates are then used for calculations. But I'm constantly hitting a wall with blackberry. I have built the Android App and it works great but can't seem to contact the server on a real blackberry device. I have tested the application in a simulator and it works perfectly but when I install it on a real phone I get no request the phone.
I have read quite a bit about the secret strings to append at the end of the url so I adapted some demo code to get me the first available transport but still nothing ...
The Application is Signed and I normally then either install it by debugging through eclipse or directly on the device from the .jad file and allow the application the required permissions.
The current code was adapted from the HTTP Connection Demo in the Blackberry SDK.
Could you have a look and give me some direction. I'm losing too much hair here ...
The Backend Service that keeps running:
public void run() {
System.out.println("Starting Loop");
Criteria cr = new Criteria();
cr.setHorizontalAccuracy(Criteria.NO_REQUIREMENT);
cr.setVerticalAccuracy(Criteria.NO_REQUIREMENT);
cr.setCostAllowed(false);
cr.setPreferredPowerConsumption(Criteria.NO_REQUIREMENT);
cr.setPreferredResponseTime(1000);
LocationProvider lp = null;
try {
lp = LocationProvider.getInstance(cr);
} catch (LocationException e) {
System.out.println("*****************Exception" + e);
}
if (lp == null) {
UiApplication.getUiApplication().invokeLater(new Runnable() {
public void run() {
Dialog.alert("GPS not supported!");
return;
}
});
} else {
System.out
.println(lp.getState() + "-" + LocationProvider.AVAILABLE);
switch (lp.getState()) {
case LocationProvider.AVAILABLE:
// System.out.println("Provider is AVAILABLE");
while (true) {
Location l = null;
int timeout = 120;
try {
l = lp.getLocation(timeout);
final Location fi = l;
System.out.println("Got a Coordinate "
+ l.getQualifiedCoordinates().getLatitude()
+ ", "
+ l.getQualifiedCoordinates().getLongitude());
System.out.println("http://" + Constants.website_base
+ "/apis/location?device_uid=" + Constants.uid
+ "&lat="
+ l.getQualifiedCoordinates().getLatitude()
+ "&lng="
+ l.getQualifiedCoordinates().getLongitude());
if (!_connectionThread.isStarted()) {
fetchPage("http://"
+ Constants.website_base
+ "/apis/location?device_uid="
+ Constants.uid
+ "&lat="
+ l.getQualifiedCoordinates().getLatitude()
+ "&lng="
+ l.getQualifiedCoordinates()
.getLongitude());
} else {
createNewFetch("http://"
+ Constants.website_base
+ "/apis/location?device_uid="
+ Constants.uid
+ "&lat="
+ l.getQualifiedCoordinates().getLatitude()
+ "&lng="
+ l.getQualifiedCoordinates()
.getLongitude());
}
Thread.sleep(1000 * 60);
} catch (LocationException e) {
System.out.println("Location timeout");
} catch (InterruptedException e) {
System.out.println("InterruptedException"
+ e.getMessage());
} catch (Exception ex) {
System.err.println(ex.getMessage());
ex.printStackTrace();
}
}
}
}
My Connection is Made with:
ConnectionFactory connFact = new ConnectionFactory();
ConnectionDescriptor connDesc = connFact.getConnection(getUrl());
// Open the connection and extract the data.
try {
// StreamConnection s = null;
// s = (StreamConnection) Connector.open(getUrl());
HttpConnection httpConn = (HttpConnection) connDesc.getConnection();
/* Data is Read here with a Input Stream */
Any Ideas ?

Figured it out!
Using a function I found online to determine which ; extension to use when connecting by using numerous Try / Catch. Then had to set the Internet APN settings. I'm in South-Africa using Vodacom so the APN is "Internet" with no Password.
Barely have hair left ....

Java writing to a text file not working properly

The Java application that I support is logging some details in a flat file. the problem I face some times is that, the entry is very low compared to the previous day. This entry is most essential because our reports are generated based on the file. I went thro code for writing I couldn't figure out any issues. the method which is writing is sync method.
Any suggestions? I can also provide the code for you is you may need?
public synchronized void log (String connID, String hotline, String callerType,
String cli, String lastMenu, String lastInput,
String status, String reason)
{
//String absoluteFP = LOG_LOC + ls + this.getFilename();
//PrintWriter pw = this.getPrintWriter(absoluteFP, true, true);
try
{
pw.print (this.getDateTime ()+ ","+connID +","+hotline+","+callerType+","+ cli+"," + lastMenu + "," + lastInput + "," + status + "," + reason);
//end 1006
pw.print (ls);
pw.flush ();
//pw.close();
}
catch (Exception e)
{
e.printStackTrace ();
return;
}
}
private synchronized PrintWriter getPrintWriter (String absoluteFileName,
boolean append, boolean autoFlush)
{
try
{
//set absolute filepath
File folder = new File (absoluteFileName).getParentFile ();//2009-01-23
File f = new File (absoluteFileName);
if (!folder.exists ())//2009-01-23
{
//System.out.println ("Call Detailed Record folder NOT FOUND! Creating a new);
folder.mkdirs ();
//System.out.println ("Configure log folder");
this.setHiddenFile (LOG_LOC);//set tmp directory to hidden folder
if (!f.exists ())
{
//System.out.println ("Creating a new Call Detailed Record...");//2009-01-23
f.createNewFile ();//2009-01-23
}
}
else
{
if (!f.exists ())
{
//System.out.println ("Creating a new Call Detailed Record...");//2009-01-23
f.createNewFile ();//2009-01-23
}
}
FileOutputStream tempFOS = new FileOutputStream (absoluteFileName, append);
if (tempFOS != null)
{
return new PrintWriter (tempFOS, autoFlush);
}
else
{
return null;
}
}
catch (Exception ex)
{
ex.printStackTrace ();
return null;
}
}
/**
* Set the given absolute file path as a hidden file.
* #param absoluteFile String
*/
private void setHiddenFile (String absoluteFile)
{
//set hidden file
//2009-01-22, KC
Runtime rt = Runtime.getRuntime ();
absoluteFile = absoluteFile.substring (0, absoluteFile.length () - 1);//2009-01-23
try
{
System.out.println (rt.exec ("attrib +H " + "\"" + absoluteFile + "\"").getInputStream ().toString ());
}
catch (IOException e)
{
e.printStackTrace ();
}
}
private String getDateTime ()
{
//2011-076-09, KC-format up to milliseconds to prevent duplicate PK in CDR table.
//return DateUtils.now ("yyyy/MM/dd HH:mm:ss");
return DateUtils.now ("yyyy/MM/dd HH:mm:ss:SSS");
//end 0609
}
private String getFilename ()
{
///return "CDR_" + port + ".dat";//2010-10-01
return port + ".dat";//2010-10-01
}
public void closePW ()
{
if (pw != null)
{
pw.close ();
}
}

You've created a FileOutputStream, but aren't closing that stream. Close that stream and try again. That might be causing the problem.
Messages are getting logged sometime because the garbage collector kicks in at some intervals and closes the FileOutStream. This then allows messages to be logged again. You're getting the unreachable error since you have a return statement in both the if & else blocks. You'll have to take the PrintWriter and FileOutStreamWriter out of the getPrintWriter put it where you usually call the getPrintWriter(). Then you'll be able to close the streams correctly. getPrintWriter should only ensure file exists, so rename it to ensureFileExistance

If you can use Apache Common IO, try this:
public synchronized void log(String connID, String hotline, String callerType,
String cli, String lastMenu, String lastInput,
String status, String reason) {
String absoluteFP = LOG_LOC + ls + this.getFilename();
File file = new File(absoluteFP);
String message = this.getDateTime() + "," + connID + "," + hotline + "," + callerType + "," + cli + "," + lastMenu + "," + lastInput + "," + status + "," + reason;
try {
// note that you must explicitly add new line character if you want the line to end with newline
FileUtils.write(file, message + "\n", "UTF-8", true);
} catch (IOException ex) {
ex.printStackTrace ();
}
}
In Common IO 2.1, you can append a file that you are writting to. You can now get rid of the closePW and getPrintwriter and since the log method is synchronized, the file can be written one at a time from the same object. However, if you try to write the same file from different object at the same time, you will end up having overwritting problem.
Also, Common IO create the missing parent folder for you automatically. There is no need to explicitly check and create the folder.