Develop Reference

Can't fetch expanded URL from a given shortened URL

I am given a shortened url and I want to get the expanded form. The below java function is used to achieve this.
public String expand(String shortenedUrl){
URL url = null;
try {
url = new URL(shortenedUrl);
} catch (MalformedURLException e) {
e.printStackTrace();
}
// open connection
HttpURLConnection httpURLConnection = null;
try {
httpURLConnection = (HttpURLConnection) url.openConnection(Proxy.NO_PROXY);
} catch (IOException e) {
e.printStackTrace();
}
// stop following browser redirect
httpURLConnection.setInstanceFollowRedirects(false);
// extract location header containing the actual destination URL
String expandedURL = httpURLConnection.getHeaderField("Location");
httpURLConnection.disconnect();
return expandedURL;
}
The code works fine in Eclipse but the same doesn't work in android.
String expandedURL = httpURLConnection.getHeaderField("Location");
The above line throws java.lang.RuntimeException: Unable to start activity ComponentInfo. And the error is pointed to the above line. If I remove the above line no error is encountered. Even I am not able to use getResponseCode() function.
int status = 0;
try {
status = httpURLConnection.getResponseCode();
} catch (IOException e) {
e.printStackTrace();
}
This piece of code also has the same problem. works in eclipse but not in android.
Any kind of help will be greatly appreciated.
Edit: The code using above function is,
ExpandUrl expandUrl = new ExpandUrl();
String expandedUrl = expandUrl.expand(shortenedUrl);
Note: The function expand is defined inside the class ExpandUrl.

Well, the code works in Eclipse but not in android. The reason is that you are doing it in Main thread and blocking it. Android wouldn't allow you to do so and throw runtime error.
I have tried to implement your code using AsyncTask in android. It works fine.
Give it a try.
To know more about AsyncTask follow: Android Documentation on AsyncTask
Good Luck!

Mailchimp Apache Error

im working with mailchimp, my objetive is to send users to the list in the mailchimp, so i used a wrapper from ecwid this one
So i did a method that send a test user to my list, i added my list id and my Api Key , but i have an error
this is my code
private void mailchimp(){
MailchimpClient client = new MailchimpClient("MY_API_KEY");
try {
EditMemberMethod.CreateOrUpdate method = new EditMemberMethod.CreateOrUpdate("MY_LIST_ID", "vasya.pupkin#gmail.com");
method.status = "subscribed";
method.merge_fields = new MailchimpObject();
method.merge_fields.mapping.put("FNAME", "Vasya");
method.merge_fields.mapping.put("LNAME", "Pupkin");
MemberInfo member = null;
Log.e("mailchimpmember",""+member);
member = client.execute(method);
} catch (IOException e) {
e.printStackTrace();
} catch (MailchimpException e) {
e.printStackTrace();
}
}
The problem is when i reach this method i get this from Apache in my android monitor at line MailchimpClient client = new MailchimpClient("MY_API_KEY");
No virtual method setConnectionManagerShared(Z)Lorg/apache/http/impl/client/HttpClientBuilder; in class Lorg/apache/http/impl/client/HttpClientBuilder; or its super classes (declaration of 'org.apache.http.impl.client.HttpClientBuilder' appears in /data/app/com.myapp.app.debug-1/split_lib_dependencies_apk.apk:classes78.dex)
at com.ecwid.maleorang.connector.HttpClientConnector.(HttpClientConnector.kt:71)
and this one
java.lang.NoClassDefFoundError: Failed resolution of: Lorg/apache/http/impl/client/HttpClientBuilder;
im really struggling to get mailchimp running in my project, i cant find a good wrapper and dont know how to properly set it up
thanks

Check this video tutorial about posting new members to MailChimp list
https://www.youtube.com/watch?v=TkRUi_vN12k
Or just try using Volley for the http requests

How to watch file for new content and retrieve that content

I have a file with name foo.txt. This file contains some text. I want to achieve following functionality:
I launch program
write something to the file (for example add one row: new string in foo.txt)
I want to get ONLY NEW content of this file.
Can you clarify the best solution of this problem? Also I want resolve related issues: in case if I modify foo.txt I want to see diff.
The closest tool which I found in Java is WatchService but if I understood right this tool can only detect type of event happened on filesystem (create file or delete or modify).

Java Diff Utils is designed for that purpose.
final List<String> originalFileContents = new ArrayList<String>();
final String filePath = "C:/Users/BackSlash/Desktop/asd.txt";
FileListener fileListener = new FileListener() {
#Override
public void fileDeleted(FileChangeEvent paramFileChangeEvent)
throws Exception {
// use this to handle file deletion event
}
#Override
public void fileCreated(FileChangeEvent paramFileChangeEvent)
throws Exception {
// use this to handle file creation event
}
#Override
public void fileChanged(FileChangeEvent paramFileChangeEvent)
throws Exception {
System.out.println("File Changed");
//get new contents
List<String> newFileContents = new ArrayList<String> ();
getFileContents(filePath, newFileContents);
//get the diff between the two files
Patch patch = DiffUtils.diff(originalFileContents, newFileContents);
//get single changes in a list
List<Delta> deltas = patch.getDeltas();
//print the changes
for (Delta delta : deltas) {
System.out.println(delta);
}
}
};
DefaultFileMonitor monitor = new DefaultFileMonitor(fileListener);
try {
FileObject fileObject = VFS.getManager().resolveFile(filePath);
getFileContents(filePath, originalFileContents);
monitor.addFile(fileObject);
monitor.start();
} catch (InterruptedException ex) {
ex.printStackTrace();
} catch (FileNotFoundException e) {
//handle
e.printStackTrace();
} catch (IOException e) {
//handle
e.printStackTrace();
}
Where getFileContents is :
void getFileContents(String path, List<String> contents) throws FileNotFoundException, IOException {
contents.clear();
BufferedReader reader = new BufferedReader(new InputStreamReader(new FileInputStream(path), "UTF-8"));
String line = null;
while ((line = reader.readLine()) != null) {
contents.add(line);
}
}
What I did:
I loaded the original file contents in a List<String>.
I used Apache Commons VFS to listen for file changes, using FileMonitor. You may ask, why? Because WatchService is only available starting from Java 7, while FileMonitor works with at least Java 5 (personal preference, if you prefer WatchService you can use it). note: Apache Commons VFS depends on Apache Commons Logging, you'll have to add both to your build path in order to make it work.
I created a FileListener, then I implemented the fileChanged method.
That method load new contents form the file, and uses Patch.diff to retrieve all differences, then prints them
I created a DefaultFileMonitor, which basically listens for changes to a file, and I added my file to it.
I started the monitor.
After the monitor is started, it will begin listening for file changes.

Organise Imports Eclipse Method

I need to know which method is called inside eclipse when I press "CTRL+ SHIFT + O" (Organise Imports), in order to invoke it after a code generation. What the name of this method and where can I find it (Package.Interface)
Thanks

"Organize Imports" action is contributed by org.eclipse.jdt.ui.actions.OrganizeImportsAction, which, in turn, calls org.eclipse.jdt.internal.corext.codemanipulation.OrganizeImportsOperation.

Finaly Managed to do it with this code (targetSite is a IWorkbench site initialized at the ame time as shell):
#Override
public void postLaunchAction(final IProject project, final IProgressMonitor monitor) throws CoreException {
super.postLaunchAction(project, monitor);
Runnable job = new Runnable() {
#Override
public void run() {
OrganizeImportsAction org = new OrganizeImportsAction(SpringServicesAction.this.targetSite);
try {
IJavaProject prj = null;
if (project.hasNature("org.eclipse.jdt.core.javanature")) {
prj = JavaCore.create(project);
}
IStructuredSelection selection = new StructuredSelection(prj);
org.run(selection);
} catch (CoreException ce) {
ce.printStackTrace();
}
}
};
this.shell.getDisplay().syncExec(job);
}

For reference, this is how I did it:
I made a large automated refactor in the codebase in our project. Due to a (i think so) bug in eclipse with refactoring static methods which are staticly imported in another file, i had to call organize imports after each refactor (also because I commit every move to git automaticly):
private void organizeImports(ICompilationUnit cu)
throws OperationCanceledException, CoreException {
cu.becomeWorkingCopy(null);
CompilationUnit unit = cu.reconcile(AST.JLS4, false, null, pm);
NullProgressMonitor pm = new NullProgressMonitor();
OrganizeImportsOperation op = new OrganizeImportsOperation(cu, unit,
true, true, true, null);
TextEdit edit = op.createTextEdit(pm);
if (edit == null) {
return;
}
JavaModelUtil.applyEdit(cu, edit, true, pm);
cu.commitWorkingCopy(true, pm);
cu.save(pm, true);
}
Disadvantagde: Discouraged access. If somebody has an idea to call this action properly without creating a new runnable and without using a shell etc., please comment.

How do I discover peers and send messages in JXTA-JXSE 2.6?

Using JXTA 2.6 from http://jxse.kenai.com/ I want to create application that can run multiple peers on one or more hosts. The peers should be able to find each other in a group and send direct messages as well as propagate messages.
What would a simple hello world type of application look like that meet these requirements?
I created this question with the intention of supplying a tutorial like answer, an answer I tried very hard to find two months ago when starting to look at JXTA for a uni project. Feel free to add your own answers or improve on mine. I will wait a few days and accept the best one.

Introduction to JXTA 2.6 Peer discovery and pipe messaging
The guide I wish I had 2 months ago =)
After spending a lot of time during a university course building
a JXTA p2p application I feel a lot of the frustrations and
confusion I went through could have been avoided with a good
starting point.
The jar files you will need can be found here:
https://oss.sonatype.org/content/repositories/comkenaijxse-057/com/kenai/jxse/jxse/2.6/jxse-2.6.jar
http://sourceforge.net/projects/practicaljxta/files/lib-dependencies-2.6.zip/download
Throw them into Yourproject/lib, open up eclipse, create a new project "Yourproject" and it should sort out
importing the libraries for you.
You will soon come to realize that almost any information on the web is out dated, very out dated.
You will also run into a lot of very confusing error messages and most of them can be avoided by
going through this check list.
Is your firewall turned off or at least open for the ports you use?
You can disable iptables using "sudo service iptables stop" under Fedora.
Check spelling! Many times when joining groups or trying to send messages spelling the group name wrong or not using the
exact same advertisement when looking for peers and services or opening pipes will cause very confusing messages.
Was trying to figure out why my pipe connections timed out when I spotted the group names being "Net info" and "Net_info".
Are you using a JXTA home directory? One per each peer you run on the same computer?
Do you really use a unique peer id? The seed provided to IDFactory need to be long enough or else you will get duplicates.
Turn off SELinux. I have had SELinux turned off during the development but can imagine it causing errors.
While it is common to group all fields together I introduce them as I go to show where they are needed.
Note: This will not work in 2.7. Some issue with PSE membership I think.
public class Hello implements DiscoveryListener, PipeMsgListener {
// When developing you should handle these exceptions, I don't to lessen the clutter of start()
public static void main(String[] args) throws PeerGroupException, IOException {
// JXTA logs a lot, you can configure it setting level here
Logger.getLogger("net.jxta").setLevel(Level.ALL);
// Randomize a port to use with a number over 1000 (for non root on unix)
// JXTA uses TCP for incoming connections which will conflict if more than
// one Hello runs at the same time on one computer.
int port = 9000 + new Random().nextInt(100);
Hello hello = new Hello(port);
hello.start();
hello.fetch_advertisements();
}
private String peer_name;
private PeerID peer_id;
private File conf;
private NetworkManager manager;
public Hello(int port) {
// Add a random number to make it easier to identify by name, will also make sure the ID is unique
peer_name = "Peer " + new Random().nextInt(1000000);
// This is what you will be looking for in Wireshark instead of an IP, hint: filter by "jxta"
peer_id = IDFactory.newPeerID(PeerGroupID.defaultNetPeerGroupID, peer_name.getBytes());
// Here the local peer cache will be saved, if you have multiple peers this must be unique
conf = new File("." + System.getProperty("file.separator") + peer_name);
// Most documentation you will find use a deprecated network manager setup, use this one instead
// ADHOC is usually a good starting point, other alternatives include Edge and Rendezvous
try {
manager = new NetworkManager(
NetworkManager.ConfigMode.ADHOC,
peer_name, conf.toURI());
}
catch (IOException e) {
// Will be thrown if you specify an invalid directory in conf
e.printStackTrace();
}
NetworkConfigurator configurator;
try {
// Settings Configuration
configurator = manager.getConfigurator();
configurator.setTcpPort(port);
configurator.setTcpEnabled(true);
configurator.setTcpIncoming(true);
configurator.setTcpOutgoing(true);
configurator.setUseMulticast(true);
configurator.setPeerID(peer_id);
}
catch (IOException e) {
// Never caught this one but let me know if you do =)
e.printStackTrace();
}
}
private static final String subgroup_name = "Make sure this is spelled the same everywhere";
private static final String subgroup_desc = "...";
private static final PeerGroupID subgroup_id = IDFactory.newPeerGroupID(PeerGroupID.defaultNetPeerGroupID, subgroup_name.getBytes());
private static final String unicast_name = "This must be spelled the same too";
private static final String multicast_name = "Or else you will get the wrong PipeID";
private static final String service_name = "And dont forget it like i did a million times";
private PeerGroup subgroup;
private PipeService pipe_service;
private PipeID unicast_id;
private PipeID multicast_id;
private PipeID service_id;
private DiscoveryService discovery;
private ModuleSpecAdvertisement mdadv;
public void start() throws PeerGroupException, IOException {
// Launch the missiles, if you have logging on and see no exceptions
// after this is ran, then you probably have at least the jars setup correctly.
PeerGroup net_group = manager.startNetwork();
// Connect to our subgroup (all groups are subgroups of Netgroup)
// If the group does not exist, it will be automatically created
// Note this is suggested deprecated, not sure what the better way is
ModuleImplAdvertisement mAdv = null;
try {
mAdv = net_group.getAllPurposePeerGroupImplAdvertisement();
} catch (Exception ex) {
System.err.println(ex.toString());
}
subgroup = net_group.newGroup(subgroup_id, mAdv, subgroup_name, subgroup_desc);
// A simple check to see if connecting to the group worked
if (Module.START_OK != subgroup.startApp(new String[0]))
System.err.println("Cannot start child peergroup");
// We will spice things up to a more interesting level by sending unicast and multicast messages
// In order to be able to do that we will create to listeners that will listen for
// unicast and multicast advertisements respectively. All messages will be handled by Hello in the
// pipeMsgEvent method.
unicast_id = IDFactory.newPipeID(subgroup.getPeerGroupID(), unicast_name.getBytes());
multicast_id = IDFactory.newPipeID(subgroup.getPeerGroupID(), multicast_name.getBytes());
pipe_service = subgroup.getPipeService();
pipe_service.createInputPipe(get_advertisement(unicast_id, false), this);
pipe_service.createInputPipe(get_advertisement(multicast_id, true), this);
// In order to for other peers to find this one (and say hello) we will
// advertise a Hello Service.
discovery = subgroup.getDiscoveryService();
discovery.addDiscoveryListener(this);
ModuleClassAdvertisement mcadv = (ModuleClassAdvertisement)
AdvertisementFactory.newAdvertisement(ModuleClassAdvertisement.getAdvertisementType());
mcadv.setName("STACK-OVERFLOW:HELLO");
mcadv.setDescription("Tutorial example to use JXTA module advertisement Framework");
ModuleClassID mcID = IDFactory.newModuleClassID();
mcadv.setModuleClassID(mcID);
// Let the group know of this service "module" / collection
discovery.publish(mcadv);
discovery.remotePublish(mcadv);
mdadv = (ModuleSpecAdvertisement)
AdvertisementFactory.newAdvertisement(ModuleSpecAdvertisement.getAdvertisementType());
mdadv.setName("STACK-OVERFLOW:HELLO");
mdadv.setVersion("Version 1.0");
mdadv.setCreator("sun.com");
mdadv.setModuleSpecID(IDFactory.newModuleSpecID(mcID));
mdadv.setSpecURI("http://www.jxta.org/Ex1");
service_id = IDFactory.newPipeID(subgroup.getPeerGroupID(), service_name.getBytes());
PipeAdvertisement pipeadv = get_advertisement(service_id, false);
mdadv.setPipeAdvertisement(pipeadv);
// Let the group know of the service
discovery.publish(mdadv);
discovery.remotePublish(mdadv);
// Start listening for discovery events, received by the discoveryEvent method
pipe_service.createInputPipe(pipeadv, this);
}
private static PipeAdvertisement get_advertisement(PipeID id, boolean is_multicast) {
PipeAdvertisement adv = (PipeAdvertisement )AdvertisementFactory.
newAdvertisement(PipeAdvertisement.getAdvertisementType());
adv.setPipeID(id);
if (is_multicast)
adv.setType(PipeService.PropagateType);
else
adv.setType(PipeService.UnicastType);
adv.setName("This however");
adv.setDescription("does not really matter");
return adv;
}
#Override public void discoveryEvent(DiscoveryEvent event) {
// Found another peer! Let's say hello shall we!
// Reformatting to create a real peer id string
String found_peer_id = "urn:jxta:" + event.getSource().toString().substring(7);
send_to_peer("Hello", found_peer_id);
}
private void send_to_peer(String message, String found_peer_id) {
// This is where having the same ID is important or else we wont be
// able to open a pipe and send messages
PipeAdvertisement adv = get_advertisement(unicast_id, false);
// Send message to all peers in "ps", just one in our case
Set<PeerID> ps = new HashSet<PeerID>();
try {
ps.add((PeerID)IDFactory.fromURI(new URI(found_peer_id)));
}
catch (URISyntaxException e) {
// The JXTA peer ids need to be formatted as proper urns
e.printStackTrace();
}
// A pipe we can use to send messages with
OutputPipe sender = null;
try {
sender = pipe_service.createOutputPipe(adv, ps, 10000);
}
catch (IOException e) {
// Thrown if there was an error opening the connection, check firewall settings
e.printStackTrace();
}
Message msg = new Message();
MessageElement fromElem = null;
MessageElement msgElem = null;
try {
fromElem = new ByteArrayMessageElement("From", null, peer_id.toString().getBytes("ISO-8859-1"), null);
msgElem = new ByteArrayMessageElement("Msg", null, message.getBytes("ISO-8859-1"), null);
} catch (UnsupportedEncodingException e) {
// Yepp, you want to spell ISO-8859-1 correctly
e.printStackTrace();
}
msg.addMessageElement(fromElem);
msg.addMessageElement(msgElem);
try {
sender.send(msg);
} catch (IOException e) {
// Check, firewall, settings.
e.printStackTrace();
}
}
#Override public void pipeMsgEvent(PipeMsgEvent event) {
// Someone is sending us a message!
try {
Message msg = event.getMessage();
byte[] msgBytes = msg.getMessageElement("Msg").getBytes(true);
byte[] fromBytes = msg.getMessageElement("From").getBytes(true);
String from = new String(fromBytes);
String message = new String(msgBytes);
System.out.println(message + " says " + from);
}
catch (Exception e) {
// You will notice that JXTA is not very specific with exceptions...
e.printStackTrace();
}
}
/**
* We will not find anyone if we are not regularly looking
*/
private void fetch_advertisements() {
new Thread("fetch advertisements thread") {
public void run() {
while(true) {
discovery.getRemoteAdvertisements(null, DiscoveryService.ADV, "Name", "STACK-OVERFLOW:HELLO", 1, null);
try {
sleep(10000);
}
catch(InterruptedException e) {}
}
}
}.start();
}
}