Develop Reference

AWS Android PubSub

I cannot get the official aws-pubsub sdk to run. I have replaced all the necessary credentials. How can I set publishing and subscribing using my Android device on Amazon IoT? I have seen every link available on the web but still cannot get it to work. Here is an idea of my project:
The company is creating air filters that transmit data on regular basis through BLE module to the android app. Now I have to use this app to publish data to Amazon IoT as soon as it gets data from the BLE.
package com.example.parasrawat2124.amazonmqtt;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import com.amazonaws.auth.CognitoCachingCredentialsProvider;
import com.amazonaws.mobileconnectors.iot.AWSIotKeystoreHelper;
import com.amazonaws.mobileconnectors.iot.AWSIotMqttClientStatusCallback;
import com.amazonaws.mobileconnectors.iot.AWSIotMqttLastWillAndTestament;
import com.amazonaws.mobileconnectors.iot.AWSIotMqttManager;
import com.amazonaws.mobileconnectors.iot.AWSIotMqttNewMessageCallback;
import com.amazonaws.mobileconnectors.iot.AWSIotMqttQos;
import com.amazonaws.regions.Region;
import com.amazonaws.regions.Regions;
import com.amazonaws.services.iot.AWSIotClient;
import com.amazonaws.services.iot.model.AttachPrincipalPolicyRequest;
import com.amazonaws.services.iot.model.CreateKeysAndCertificateRequest;
import com.amazonaws.services.iot.model.CreateKeysAndCertificateResult;
import java.io.UnsupportedEncodingException;
import java.security.KeyStore;
import java.util.UUID;
public class MainActivity extends AppCompatActivity {
static final String LOG_TAG = MainActivity.class.getCanonicalName();
// --- Constants to modify per your configuration ---
// IoT endpoint
// AWS Iot CLI describe-endpoint call returns: XXXXXXXXXX.iot.<region>.amazonaws.com
private static final String CUSTOMER_SPECIFIC_ENDPOINT = "a1j3ds5m9dpp07.iot.us-west-2.amazonaws.com";
// Cognito pool ID. For this app, pool needs to be unauthenticated pool with
// AWS IoT permissions.
private static final String COGNITO_POOL_ID = "us-west-2_iQ1FI8tfj";
// Name of the AWS IoT policy to attach to a newly created certificate
private static final String AWS_IOT_POLICY_NAME = "PMQTT";
// Region of AWS IoT
private static final Regions MY_REGION = Regions.US_EAST_1;
// Filename of KeyStore file on the filesystem
private static final String KEYSTORE_NAME = "iot_keystore";
// Password for the private key in the KeyStore
private static final String KEYSTORE_PASSWORD = "password";
// Certificate and key aliases in the KeyStore
private static final String CERTIFICATE_ID = "default";
EditText txtSubcribe;
EditText txtTopic;
EditText txtMessage;
TextView tvLastMessage;
TextView tvClientId;
TextView tvStatus;
Button btnConnect;
Button btnSubscribe;
Button btnPublish;
Button btnDisconnect;
AWSIotClient mIotAndroidClient;
AWSIotMqttManager mqttManager;
String clientId;
String keystorePath;
String keystoreName;
String keystorePassword;
KeyStore clientKeyStore = null;
String certificateId;
CognitoCachingCredentialsProvider credentialsProvider;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
txtSubcribe = (EditText) findViewById(R.id.txtSubsribe);
txtTopic = (EditText) findViewById(R.id.txtTopic);
txtMessage = (EditText) findViewById(R.id.txtMessage);
tvLastMessage = (TextView) findViewById(R.id.tvLastMessage);
tvClientId = (TextView) findViewById(R.id.tvClientId);
tvStatus = (TextView) findViewById(R.id.tvStatus);
btnConnect = (Button) findViewById(R.id.btnConnect);
btnConnect.setOnClickListener(connectClick);
btnConnect.setEnabled(false);
btnSubscribe = (Button) findViewById(R.id.btnSubscribe);
btnSubscribe.setOnClickListener(subscribeClick);
btnPublish = (Button) findViewById(R.id.btnPublish);
btnPublish.setOnClickListener(publishClick);
btnDisconnect = (Button) findViewById(R.id.btnDisconnect);
btnDisconnect.setOnClickListener(disconnectClick);
// MQTT client IDs are required to be unique per AWS IoT account.
// This UUID is "practically unique" but does not _guarantee_
// uniqueness.
clientId = UUID.randomUUID().toString();
tvClientId.setText(clientId);
// Initialize the AWS Cognito credentials provider
credentialsProvider = new CognitoCachingCredentialsProvider(
getApplicationContext(), // context
COGNITO_POOL_ID, // Identity Pool ID
MY_REGION // Region
);
Region region = Region.getRegion(MY_REGION);
// MQTT Client
mqttManager = new AWSIotMqttManager(clientId, CUSTOMER_SPECIFIC_ENDPOINT);
// Set keepalive to 10 seconds. Will recognize disconnects more quickly but will also send
// MQTT pings every 10 seconds.
mqttManager.setKeepAlive(10);
// Set Last Will and Testament for MQTT. On an unclean disconnect (loss of connection)
// AWS IoT will publish this message to alert other clients.
AWSIotMqttLastWillAndTestament lwt = new AWSIotMqttLastWillAndTestament("my/lwt/topic",
"Android client lost connection", AWSIotMqttQos.QOS0);
mqttManager.setMqttLastWillAndTestament(lwt);
// IoT Client (for creation of certificate if needed)
mIotAndroidClient = new AWSIotClient(credentialsProvider);
mIotAndroidClient.setRegion(region);
keystorePath = getFilesDir().getPath();
keystoreName = KEYSTORE_NAME;
keystorePassword = KEYSTORE_PASSWORD;
certificateId = CERTIFICATE_ID;
// To load cert/key from keystore on filesystem
try {
if (AWSIotKeystoreHelper.isKeystorePresent(keystorePath, keystoreName)) {
if (AWSIotKeystoreHelper.keystoreContainsAlias(certificateId, keystorePath,
keystoreName, keystorePassword)) {
Log.i(LOG_TAG, "Certificate " + certificateId
+ " found in keystore - using for MQTT.");
// load keystore from file into memory to pass on connection
clientKeyStore = AWSIotKeystoreHelper.getIotKeystore(certificateId,
keystorePath, keystoreName, keystorePassword);
btnConnect.setEnabled(true);
} else {
Log.i(LOG_TAG, "Key/cert " + certificateId + " not found in keystore.");
}
} else {
Log.i(LOG_TAG, "Keystore " + keystorePath + "/" + keystoreName + " not found.");
}
} catch (Exception e) {
Log.e(LOG_TAG, "An error occurred retrieving cert/key from keystore.", e);
}
if (clientKeyStore == null) {
Log.i(LOG_TAG, "Cert/key was not found in keystore - creating new key and certificate.");
new Thread(new Runnable() {
#Override
public void run() {
try {
// Create a new private key and certificate. This call
// creates both on the server and returns them to the
// device.
CreateKeysAndCertificateRequest createKeysAndCertificateRequest =
new CreateKeysAndCertificateRequest();
createKeysAndCertificateRequest.setSetAsActive(true);
final CreateKeysAndCertificateResult createKeysAndCertificateResult;
createKeysAndCertificateResult =
mIotAndroidClient.createKeysAndCertificate(createKeysAndCertificateRequest);
Log.i(LOG_TAG,
"Cert ID: " +
createKeysAndCertificateResult.getCertificateId() +
" created.");
// store in keystore for use in MQTT client
// saved as alias "default" so a new certificate isn't
// generated each run of this application
AWSIotKeystoreHelper.saveCertificateAndPrivateKey(certificateId,
createKeysAndCertificateResult.getCertificatePem(),
createKeysAndCertificateResult.getKeyPair().getPrivateKey(),
keystorePath, keystoreName, keystorePassword);
// load keystore from file into memory to pass on
// connection
clientKeyStore = AWSIotKeystoreHelper.getIotKeystore(certificateId,
keystorePath, keystoreName, keystorePassword);
// Attach a policy to the newly created certificate.
// This flow assumes the policy was already created in
// AWS IoT and we are now just attaching it to the
// certificate.
AttachPrincipalPolicyRequest policyAttachRequest =
new AttachPrincipalPolicyRequest();
policyAttachRequest.setPolicyName(AWS_IOT_POLICY_NAME);
policyAttachRequest.setPrincipal(createKeysAndCertificateResult
.getCertificateArn());
mIotAndroidClient.attachPrincipalPolicy(policyAttachRequest);
runOnUiThread(new Runnable() {
#Override
public void run() {
btnConnect.setEnabled(true);
}
});
} catch (Exception e) {
Log.e(LOG_TAG,
"Exception occurred when generating new private key and certificate.",
e);
}
}
}).start();
}
}
View.OnClickListener connectClick = new View.OnClickListener() {
#Override
public void onClick(View v) {
Log.d(LOG_TAG, "clientId = " + clientId);
try {
mqttManager.connect(clientKeyStore, new AWSIotMqttClientStatusCallback() {
#Override
public void onStatusChanged(final AWSIotMqttClientStatus status,
final Throwable throwable) {
Log.d(LOG_TAG, "Status = " + String.valueOf(status));
runOnUiThread(new Runnable() {
#Override
public void run() {
if (status == AWSIotMqttClientStatus.Connecting) {
tvStatus.setText("Connecting...");
} else if (status == AWSIotMqttClientStatus.Connected) {
tvStatus.setText("Connected");
} else if (status == AWSIotMqttClientStatus.Reconnecting) {
if (throwable != null) {
Log.e(LOG_TAG, "Connection error.", throwable);
}
tvStatus.setText("Reconnecting");
} else if (status == AWSIotMqttClientStatus.ConnectionLost) {
if (throwable != null) {
Log.e(LOG_TAG, "Connection error.", throwable);
}
tvStatus.setText("Disconnected");
} else {
tvStatus.setText("Disconnected");
}
}
});
}
});
} catch (final Exception e) {
Log.e(LOG_TAG, "Connection error.", e);
tvStatus.setText("Error! " + e.getMessage());
}
}
};
View.OnClickListener subscribeClick = new View.OnClickListener() {
#Override
public void onClick(View v) {
final String topic = txtSubcribe.getText().toString();
Log.d(LOG_TAG, "topic = " + topic);
try {
mqttManager.subscribeToTopic(topic, AWSIotMqttQos.QOS0,
new AWSIotMqttNewMessageCallback() {
#Override
public void onMessageArrived(final String topic, final byte[] data) {
runOnUiThread(new Runnable() {
#Override
public void run() {
try {
String message = new String(data, "UTF-8");
Log.d(LOG_TAG, "Message arrived:");
Log.d(LOG_TAG, " Topic: " + topic);
Log.d(LOG_TAG, " Message: " + message);
tvLastMessage.setText(message);
} catch (UnsupportedEncodingException e) {
Log.e(LOG_TAG, "Message encoding error.", e);
}
}
});
}
});
} catch (Exception e) {
Log.e(LOG_TAG, "Subscription error.", e);
}
}
};
View.OnClickListener publishClick = new View.OnClickListener() {
#Override
public void onClick(View v) {
final String topic = txtTopic.getText().toString();
final String msg = txtMessage.getText().toString();
try {
mqttManager.publishString(msg, topic, AWSIotMqttQos.QOS0);
} catch (Exception e) {
Log.e(LOG_TAG, "Publish error.", e);
}
}
};
View.OnClickListener disconnectClick = new View.OnClickListener() {
#Override
public void onClick(View v) {
try {
mqttManager.disconnect();
} catch (Exception e) {
Log.e(LOG_TAG, "Disconnect error.", e);
}
}
};
}
And my console message:
07-23 12:06:20.595 18136-18168/com.example.parasrawat2124.amazonmqtt D/CognitoCachingCredentialsProvider: Clearing credentials from SharedPreferences
07-23 12:06:20.898 18136-18168/com.example.parasrawat2124.amazonmqtt E/com.example.parasrawat2124.amazonmqtt.MainActivity: Exception occurred when generating new private key and certificate.
com.amazonaws.AmazonServiceException: 1 validation error detected: Value 'us-west-2_iQ1FI8tfj' at 'identityPoolId' failed to satisfy constraint: Member must satisfy regular expression pattern: [\w-]+:[0-9a-f-]+ (Service: AmazonCognitoIdentity; Status Code: 400; Error Code: ValidationException; Request ID: b696c58e-8e42-11e8-b181-f1f1e5db8378)
at com.amazonaws.http.AmazonHttpClient.handleErrorResponse(AmazonHttpClient.java:730)
at com.amazonaws.http.AmazonHttpClient.executeHelper(AmazonHttpClient.java:405)
at com.amazonaws.http.AmazonHttpClient.execute(AmazonHttpClient.java:212)
at com.amazonaws.services.cognitoidentity.AmazonCognitoIdentityClient.invoke(AmazonCognitoIdentityClient.java:566)
at com.amazonaws.services.cognitoidentity.AmazonCognitoIdentityClient.getId(AmazonCognitoIdentityClient.java:448)
at com.amazonaws.auth.AWSAbstractCognitoIdentityProvider.getIdentityId(AWSAbstractCognitoIdentityProvider.java:172)
at com.amazonaws.auth.AWSEnhancedCognitoIdentityProvider.refresh(AWSEnhancedCognitoIdentityProvider.java:76)
at com.amazonaws.auth.CognitoCredentialsProvider.retryRefresh(CognitoCredentialsProvider.java:693)
at com.amazonaws.auth.CognitoCredentialsProvider.startSession(CognitoCredentialsProvider.java:665)
at com.amazonaws.auth.CognitoCredentialsProvider.getCredentials(CognitoCredentialsProvider.java:444)
at com.amazonaws.auth.CognitoCachingCredentialsProvider.getCredentials(CognitoCachingCredentialsProvider.java:485)
at com.amazonaws.auth.CognitoCachingCredentialsProvider.getCredentials(CognitoCachingCredentialsProvider.java:77)
at com.amazonaws.services.iot.AWSIotClient.invoke(AWSIotClient.java:7048)
at com.amazonaws.services.iot.AWSIotClient.createKeysAndCertificate(AWSIotClient.java:1119)
at com.example.parasrawat2124.amazonmqtt.MainActivity$1.run(MainActivity.java:177)
at java.lang.Thread.run(Thread.java:764)

I am sorry for asking a question based on such few credentials. I figured out the actual problem. The steps given in the official Github Readme file are correct but you need to consider some options below in case you encounter errors:
Don't use the default value of keystore credentials as written in the readme file. Create your own Keystore and then put those new credentials and alias in the app.
After the last step which is creating a policy in IoT , I would recommend creating a thing and a certificate and attach this policy to that certificate. This was the problem that occurred in my case.

Sending Email in Android using JavaMail API without using mailing APP

Sending Email in Android using JavaMail API without using the default/built-in app
Using this tutorial, I've loaded up the code into a sample android project and imported the libraries. Changed the parameters in the lines:
send.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
try {
GMailSender sender = new GMailSender("sender#gmail.com", "sender_password");
sender.sendMail("This is Subject", "This is Body", "sender#gmail.com", "recipient#gmail.com");
} catch (Exception e) {
Log.e("SendMail", e.getMessage(), e);
}
}
});
Wanted to test it out and in this code, the try block of code gets executed successfully when I press the button, but I don't receive the mail, nor do I get any errors. Since there's no readme or any guidelines as to how to use this code, I have no choice but to ask what I'm doing wrong.
Just to clear the confusion, I've put the senders email instead of sender#gmail.com, same goes for password and recipient#gmail.com.
I've also added the INTERNET permission to the manifest.

If you want to use mailgun instead you can do it like this:
public void sendEmailInBackground(final String subject, final String body, final String... toAddress) {
AsyncTask task = new AsyncTask() {
#Override
protected Object doInBackground(Object[] objects) {
String hostname = "smpt.mailgun.org";
int port = 25;
String login = "login";
String password = "password";
String from = "from#example.com";
AuthenticatingSMTPClient client = null;
try {
client = new AuthenticatingSMTPClient();
// optionally set a timeout to have a faster feedback on errors
client.setDefaultTimeout(10 * 1000);
// you connect to the SMTP server
client.connect(hostname, port);
// you say helo and you specify the host you are connecting from, could be anything
client.ehlo("localhost");
// if your host accepts STARTTLS, we're good everything will be encrypted, otherwise we're done here
if (client.execTLS()) {
client.auth(AuthenticatingSMTPClient.AUTH_METHOD.LOGIN, login, password);
checkReply(client);
client.setSender(from);
checkReply(client);
String address = "";
if (toAddress != null) {
for (String to : toAddress) {
if(to != null && to.length() > 0) {
client.addRecipient(to);
if (address.length() == 0) {
address += ",";
}
address += to;
}
}
}
if(address.length() == 0){
logger.warning("No address specified for mail message");
return null;
}
checkReply(client);
Writer writer = client.sendMessageData();
if (writer != null) {
SimpleSMTPHeader header = new SimpleSMTPHeader(from, address, subject);
writer.write(header.toString());
writer.write(body);
writer.close();
if (!client.completePendingCommand()) {// failure
throw new IOException("Failure to send the email " + client.getReply() + client.getReplyString());
}
} else {
throw new IOException("Failure to send the email " + client.getReply() + client.getReplyString());
}
} else {
throw new IOException("STARTTLS was not accepted " + client.getReply() + client.getReplyString());
}
} catch (IOException | NoSuchAlgorithmException | InvalidKeyException | InvalidKeySpecException e) {
logger.severe("Error sending email",e);
} finally {
if (client != null) {
try {
client.logout();
client.disconnect();
} catch (Exception e) {
logger.warning("Error closing email client: " + e.getMessage());
}
}
}
return null;
}
};
task.execute();
}
private static void checkReply(SMTPClient sc) throws IOException {
if (SMTPReply.isNegativeTransient(sc.getReplyCode())) {
throw new IOException("Transient SMTP error " + sc.getReplyString());
} else if (SMTPReply.isNegativePermanent(sc.getReplyCode())) {
throw new IOException("Permanent SMTP error " + sc.getReplyString());
}
}

RxJava- RxAndroid form validation on dynamic EditText

I have form that can have variable number of EditText that needs to be validated before form submission. I can perform validation check if EditTexts are fixed in number like following -
Observable<CharSequence> emailObservable = RxTextView.textChanges(editEmail).skip(1);
Observable<CharSequence> passwordObservable = RxTextView.textChanges(editPassword).skip(1);
mFormValidationSubscription = Observable.combineLatest(emailObservable, passwordObservable,
(newEmail, newPassword) -> {
boolean emailValid = !TextUtils.isEmpty(newEmail) && android.util.Patterns.EMAIL_ADDRESS.matcher(newEmail).matches();
if(!emailValid) {
emailInputLayout.setError(getString(R.string.error_invalid_email));
emailInputLayout.setErrorEnabled(true);
}else {
emailInputLayout.setError(null);
emailInputLayout.setErrorEnabled(false);
}
boolean passValid = !TextUtils.isEmpty(newPassword) && newPassword.length() > 4;
if (!passValid) {
passwordInputLayout.setError(getString(R.string.error_invalid_password));
passwordInputLayout.setErrorEnabled(true);
} else {
passwordInputLayout.setError(null);
passwordInputLayout.setErrorEnabled(true);
}
return emailValid && passValid;
}).subscribe(isValid ->{
mSubmitButton.setEnabled(isValid);
});
But now as there are variable number of inputs I tried creating a list of Observable<CharSequence> and Observable.combineLatest() but I'm stuck as to proceed with that.
List<Observable<CharSequence>> observableList = new ArrayList<>();
for(InputRule inputRule : mMaterial.getRules()) {
View vInputRow = inflater.inflate(R.layout.item_material_input_row, null, false);
StyledEditText styledEditText = ((StyledEditText)vInputRow.findViewById(R.id.edit_input));
styledEditText.setHint(inputRule.getName());
Observable<CharSequence> observable = RxTextView.textChanges(styledEditText).skip(1);
observableList.add(observable);
linearLayout.addView(vInputRow);
}
Observable.combineLatest(observableList,......); // What should go in place of these "......"
How can I perform checks for a valid charsequence for each input field. I looked into flatMap(), map(), filter() methods but I don't know how to use them.

Yes, you process abitrary number of Observables in .combineLatest(), but there is still workaround. I got interested in this problem and came up with following solution- we can store information about some data source - last value and source ID (String and resource id) and tunnell all data into some common pipe. For that we can use PublishSubject. We also need to track connection state, for that we should save Subscription to each source on subscription and sever it when we unsubscribe from that source.
We store last data from each source, so we can tell user what source just emitted new value, callback will only contain source id. User can get last value of any source by source id.
I came up with the following code:
import android.util.Log;
import android.widget.EditText;
import com.jakewharton.rxbinding.widget.RxTextView;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
import rx.Observable;
import rx.Subscription;
import rx.functions.Action1;
import rx.subjects.PublishSubject;
public class MultiSourceCombinator {
String LOG_TAG = MultiSourceCombinator.class.getSimpleName();
/**
* We can't handle arbitrary number of sources by CombineLatest, but we can pass data along
* with information about source (sourceId)
*/
private static class SourceData{
String data = "";
Integer sourceId = 0;
}
/**
* Keep id of source, subscription to that source and last value emitted
* by source. This value is passed when source is attached
*/
private class SourceInfo{
Subscription sourceTracking;
Integer sourceId;
SourceData lastData;
SourceInfo(int sourceId, String data){
this.sourceId = sourceId;
// initialize last data with empty value
SourceData d = new SourceData();
d.data = data;
d.sourceId = sourceId;
this.lastData = d;
}
}
/**
* We can tunnel data from all sources into single pipe. Subscriber can treat it as
* Observable<SourceData>
*/
private PublishSubject<SourceData> dataDrain;
/**
* Stores all sources by their ids.
*/
Map<Integer, SourceInfo> sources;
/**
* Callback, notified whenever source emit new data. it receives source id.
* When notification is received by client, it can get value from source by using
* getLastSourceValue(sourceId) method
*/
Action1<Integer> sourceUpdateCallback;
public MultiSourceCombinator(){
dataDrain = PublishSubject.create();
sources = new HashMap<>();
sourceUpdateCallback = null;
// We have to process data, ccoming from common pipe
dataDrain.asObservable()
.subscribe(newValue -> {
if (sourceUpdateCallback == null) {
Log.w(LOG_TAG, "Source " + newValue.sourceId + "emitted new value, " +
"but used did't set callback ");
} else {
sourceUpdateCallback.call(newValue.sourceId);
}
});
}
/**
* Disconnect from all sources (sever Connection (s))
*/
public void stop(){
Log.i(LOG_TAG, "Unsubscribing from all sources");
// copy references to aboid ConcurrentModificatioinException
ArrayList<SourceInfo> t = new ArrayList(sources.values());
for (SourceInfo si : t){
removeSource(si.sourceId);
}
// right now there must be no active sources
if (!sources.isEmpty()){
throw new RuntimeException("There must be no active sources");
}
}
/**
* Create new source from edit field, subscribe to this source and save subscription for
* further tracking.
* #param editText
*/
public void addSource(EditText editText, int sourceId){
if (sources.containsKey(sourceId)){
Log.e(LOG_TAG, "Source with id " + sourceId + " already exist");
return;
}
Observable<CharSequence> source = RxTextView.textChanges(editText).skip(1);
String lastValue = editText.getText().toString();
Log.i(LOG_TAG, "Source with id " + sourceId + " has data " + lastValue);
// Redirect data coming from source to common pipe, to do that attach source id to
// data string
Subscription sourceSubscription = source.subscribe(text -> {
String s = new String(text.toString());
SourceData nextValue = new SourceData();
nextValue.sourceId = sourceId;
nextValue.data = s;
Log.i(LOG_TAG, "Source " + sourceId + "emits new value: " + s);
// save vlast value
sources.get(sourceId).lastData.data = s;
// pass new value down pipeline
dataDrain.onNext(nextValue);
});
// create SourceInfo
SourceInfo sourceInfo = new SourceInfo(sourceId, lastValue);
sourceInfo.sourceTracking = sourceSubscription;
sources.put(sourceId, sourceInfo);
}
/**
* Unsubscribe source from common pipe and remove it from list of sources
* #param sourceId
* #throws IllegalArgumentException
*/
public void removeSource(Integer sourceId) throws IllegalArgumentException {
if (!sources.containsKey(sourceId)){
throw new IllegalArgumentException("There is no source with id: " + sourceId);
}
SourceInfo si = sources.get(sourceId);
Subscription s = si.sourceTracking;
if (null != s && !s.isUnsubscribed()){
Log.i(LOG_TAG, "source " + sourceId + " is active, unsubscribing from it");
si.sourceTracking.unsubscribe();
si.sourceTracking = null;
}
// source is disabled, remove it from list
Log.i(LOG_TAG, "Source " + sourceId + " is disabled ");
sources.remove(sourceId);
}
/**
* User can get value from any source by using source ID.
* #param sourceId
* #return
* #throws IllegalArgumentException
*/
public String getLastSourceValue(Integer sourceId) throws IllegalArgumentException{
if (!sources.containsKey(sourceId)){
throw new IllegalArgumentException("There is no source with id: " + sourceId);
}
String lastValue = sources.get(sourceId).lastData.data;
return lastValue;
}
public void setSourceUpdateCallback(Action1<Integer> sourceUpdateFeedback) {
this.sourceUpdateCallback = sourceUpdateFeedback;
}
}
And we can use it in UI like this:
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.widget.EditText;
import android.widget.Toast;
import butterknife.BindView;
import butterknife.ButterKnife;
public class EdiTextTestActivity extends Activity {
#BindView(R.id.aet_et1)
public EditText et1;
#BindView(R.id.aet_et2)
public EditText et2;
#BindView(R.id.aet_et3)
public EditText et3;
private MultiSourceCombinator multiSourceCombinator;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_edit_text_test);
ButterKnife.bind(this);
multiSourceCombinator = new MultiSourceCombinator();
multiSourceCombinator.setSourceUpdateCallback(id -> {
Toast.makeText(EdiTextTestActivity.this, "New value from source: " + id + " : " +
multiSourceCombinator.getLastSourceValue(id), Toast.LENGTH_SHORT).show();
});
}
#Override
protected void onPause() {
// stop tracking all fields
multiSourceCombinator.stop();
super.onPause();
}
#Override
protected void onResume() {
super.onResume();
// Register fields
multiSourceCombinator.addSource(et1, R.id.aet_et1);
multiSourceCombinator.addSource(et2, R.id.aet_et2);
multiSourceCombinator.addSource(et3, R.id.aet_et3);
}
}

I have a solution for you without using lambda expressions (as I could not compile it with lambdas).
Use the same operator as you wanted:
public static <T, R> Observable<R> combineLatest(List<? extends Observable<? extends T>> sources, FuncN<? extends R> combineFunction)
Observable.combineLatest(observableList, new FuncN<Boolean>() {
#Override
public Boolean call(Object... objects) {
boolean isValid = true;
CharSequence input;
for (int i = 0; i < objects.length; i++) {
input = (CharSequence) objects[i];
switch (i) {
case 1:
//First text field value
break;
case 2:
//Second text field value
break;
default:
isValid = false;
}
}
return isValid;
}
})
The reason lambda expressions don't work is probably in second parameter of the function combineLatest(...):
public interface FuncN<R> extends Function {
R call(Object... args);
}
According to this post implementing Arbitrary Number of Arguments is hard to do and workarounds need to be created.
RxJava v2 is compatible with Java 8 and has a different implementation of combineLatest

I used R. Zagórski's answer as guide on how to do this with Kotlin
This is what worked for me in the end.
val ob1 = RxTextView.textChanges(field1).skip(1)
val ob2 = RxTextView.textChanges(field2).skip(1)
val ob3 = RxTextView.textChanges(field3).skip(1)
val observableList = arrayListOf<Observable<CharSequence>>()
observableList.add(ob1)
observableList.add(ob3)
val formValidator = Observable.combineLatest(observableList, {
var isValid = true
it.forEach {
val string = it.toString()
if (string.isEmpty()) {
isValid = false
}
}
return#combineLatest isValid
})
formValidator.subscribe { isValid ->
if (isValid) {
//do something
} else {
//do something
}
}

building, authenticating, and parsing with the Smack library

I am trying to connect to Firebase Cloud Messaging by using smack library.
I don't have much knowledge of the Smack API. After reading the Firebase docs, I see that the connection must be authenticated and there are a series of responses back and forth between "app server" and Cloud Connection Servers. According to the docs, I must create a Sasl Plain authentication. I don't know how to implement this. But after reading some posts by other StackOverFlow users I see that I must create an authentication class. Specifically, I was reviewing the answers and comments on "Gtalk XMPP SASL authentication failed using mechanism X-OAUTH2?" These responses that are between CCS and the "app server" are enclosed in and tags. I dont know how to use Smack to get or build these responses. I do have my connection set up with XMPP, and I've tried setting a addAsyncStanzListener to my XMPP connection with the hopes of getting some of these responses from CCS. But, nothing comes in. The responses between "app server" and CCS could be found in this link https://firebase.google.com/docs/cloud-messaging/server#connecting
Does anyone here know how to proceed from here. I think that Smack is not well documented and having little knowledge of XMPP makes it even worse. There are all these classes, Packets, extensions, IQ class, XML pull parsers etc.
Any rough structure on the set up would be ideal.
Thanks

Here is a snippet of my server code that I use with Firebase. If you want to understand in more detail try this blog post (it is how I figured out how to get everything to work in the end): http://www.grokkingandroid.com/xmpp-server-google-cloud-messaging/
In order to get the code below to work you will need to go to the Firebase console and go to project settings
From here you will need to take note of your Server Key and Sender ID and replace it in the code snippet below (it is near the bottom of the code) and save it in your path as SmackCcsClient.class
After doing that you can compile and run your server through the command promt:
// Set up java file (replace PATH_TO_WHERE_YOUR_CLASS_IS with your own path and make sure to put the json and smack JARs there as well
javac -d PATH_TO_WHERE_YOUR_CLASS_IS -sourcepath src -cp PATH_TO_WHERE_YOUR_CLASS_IS\json-simple-1.1.1.jar;PATH_TO_WHERE_YOUR_CLASS_IS\smack-3.4.1-0cec571.jar PATH_TO_WHERE_YOUR_CLASS_IS\SmackCcsClient.java
// Run
java -cp PATH_TO_WHERE_YOUR_CLASS_IS;PATH_TO_WHERE_YOUR_CLASS_IS\json-simple-1.1.1.jar;PATH_TO_WHERE_YOUR_CLASS_IS\smack-3.4.1-0cec571.jar SmackCcsClient
/*
SmackCcsClient:
import org.jivesoftware.smack.ConnectionConfiguration;
import org.jivesoftware.smack.ConnectionConfiguration.SecurityMode;
import org.jivesoftware.smack.ConnectionListener;
import org.jivesoftware.smack.PacketInterceptor;
import org.jivesoftware.smack.PacketListener;
import org.jivesoftware.smack.XMPPConnection;
import org.jivesoftware.smack.XMPPException;
import org.jivesoftware.smack.filter.PacketTypeFilter;
import org.jivesoftware.smack.packet.DefaultPacketExtension;
import org.jivesoftware.smack.packet.Message;
import org.jivesoftware.smack.packet.Packet;
import org.jivesoftware.smack.packet.PacketExtension;
import org.jivesoftware.smack.provider.PacketExtensionProvider;
import org.jivesoftware.smack.provider.ProviderManager;
import org.jivesoftware.smack.util.StringUtils;
import org.json.simple.JSONValue;
import org.json.simple.parser.ParseException;
import org.xmlpull.v1.XmlPullParser;
import java.util.HashMap;
import java.util.Map;
import java.util.Random;
import java.util.logging.Level;
import java.util.logging.Logger;
import java.io.*;
import javax.net.ssl.SSLSocketFactory;
/**
* Sample Smack implementation of a client for GCM Cloud Connection Server.
*
* For illustration purposes only.
*/
public class SmackCcsClient {
static final String REG_ID_STORE = "gcmchat.txt";
static final String MESSAGE_KEY = "SM";
Logger logger = Logger.getLogger("SmackCcsClient");
public static final String GCM_SERVER = "fcm-xmpp.googleapis.com";
public static final int GCM_PORT = 5235;
public static final String GCM_ELEMENT_NAME = "gcm";
public static final String GCM_NAMESPACE = "google:mobile:data";
static Random random = new Random();
XMPPConnection connection;
ConnectionConfiguration config;
/**
* XMPP Packet Extension for GCM Cloud Connection Server.
*/
class GcmPacketExtension extends DefaultPacketExtension {
String json;
public GcmPacketExtension(String json) {
super(GCM_ELEMENT_NAME, GCM_NAMESPACE);
this.json = json;
}
public String getJson() {
return json;
}
#Override
public String toXML() {
return String.format("<%s xmlns=\"%s\">%s</%s>", GCM_ELEMENT_NAME,
GCM_NAMESPACE, json, GCM_ELEMENT_NAME);
}
#SuppressWarnings("unused")
public Packet toPacket() {
return new Message() {
// Must override toXML() because it includes a <body>
#Override
public String toXML() {
StringBuilder buf = new StringBuilder();
buf.append("<message");
if (getXmlns() != null) {
buf.append(" xmlns=\"").append(getXmlns()).append("\"");
}
if (getLanguage() != null) {
buf.append(" xml:lang=\"").append(getLanguage())
.append("\"");
}
if (getPacketID() != null) {
buf.append(" id=\"").append(getPacketID()).append("\"");
}
if (getTo() != null) {
buf.append(" to=\"")
.append(StringUtils.escapeForXML(getTo()))
.append("\"");
}
if (getFrom() != null) {
buf.append(" from=\"")
.append(StringUtils.escapeForXML(getFrom()))
.append("\"");
}
buf.append(">");
buf.append(GcmPacketExtension.this.toXML());
buf.append("</message>");
return buf.toString();
}
};
}
}
public SmackCcsClient() {
// Add GcmPacketExtension
ProviderManager.getInstance().addExtensionProvider(GCM_ELEMENT_NAME,
GCM_NAMESPACE, new PacketExtensionProvider() {
#Override
public PacketExtension parseExtension(XmlPullParser parser)
throws Exception {
String json = parser.nextText();
GcmPacketExtension packet = new GcmPacketExtension(json);
return packet;
}
});
}
/**
* Returns a random message id to uniquely identify a message.
*
* <p>
* Note: This is generated by a pseudo random number generator for
* illustration purpose, and is not guaranteed to be unique.
*
*/
public String getRandomMessageId() {
return "m-" + Long.toString(random.nextLong());
}
/**
* Sends a downstream GCM message.
*/
public void send(String jsonRequest) {
Packet request = new GcmPacketExtension(jsonRequest).toPacket();
connection.sendPacket(request);
}
/**
* Handles an upstream data message from a device application.
*
* <p>
* This sample echo server sends an echo message back to the device.
* Subclasses should override this method to process an upstream message.
*/
public void handleIncomingDataMessage(Map<String, Object> jsonObject) {
String from = jsonObject.get("from").toString();
// PackageName of the application that sent this message.
String category = jsonObject.get("category").toString();
// Use the packageName as the collapseKey in the echo packet
String collapseKey = "echo:CollapseKey";
#SuppressWarnings("unchecked")
Map<String, String> payload = (Map<String, String>) jsonObject
.get("data");
String messageText = payload.get("message_text");
String messageFrom = payload.get("message_userfrom");
String messageTime = payload.get("message_timestamp");
String toUser = payload.get("message_recipient");
payload.put("message_text", messageText);
payload.put("message_userfrom", messageFrom);
payload.put("message_timestamp", messageTime);
String message = createJsonMessage(toUser, getRandomMessageId(),
payload, collapseKey, null, false);
send(message);
}
/**
* Handles an ACK.
*
* <p>
* By default, it only logs a INFO message, but subclasses could override it
* to properly handle ACKS.
*/
public void handleAckReceipt(Map<String, Object> jsonObject) {
String messageId = jsonObject.get("message_id").toString();
String from = jsonObject.get("from").toString();
logger.log(Level.INFO, "handleAckReceipt() from: " + from
+ ", messageId: " + messageId);
}
/**
* Handles a NACK.
*
* <p>
* By default, it only logs a INFO message, but subclasses could override it
* to properly handle NACKS.
*/
public void handleNackReceipt(Map<String, Object> jsonObject) {
String messageId = jsonObject.get("message_id").toString();
String from = jsonObject.get("from").toString();
logger.log(Level.INFO, "handleNackReceipt() from: " + from
+ ", messageId: " + messageId);
}
/**
* Creates a JSON encoded GCM message.
*
* #param to
* RegistrationId of the target device (Required).
* #param messageId
* Unique messageId for which CCS will send an "ack/nack"
* (Required).
* #param payload
* Message content intended for the application. (Optional).
* #param collapseKey
* GCM collapse_key parameter (Optional).
* #param timeToLive
* GCM time_to_live parameter (Optional).
* #param delayWhileIdle
* GCM delay_while_idle parameter (Optional).
* #return JSON encoded GCM message.
*/
public static String createJsonMessage(String to, String messageId,
Map<String, String> payload, String collapseKey, Long timeToLive,
Boolean delayWhileIdle) {
Map<String, Object> message = new HashMap<String, Object>();
message.put("to", to);
if (collapseKey != null) {
message.put("collapse_key", collapseKey);
}
if (timeToLive != null) {
message.put("time_to_live", timeToLive);
}
if (delayWhileIdle != null && delayWhileIdle) {
message.put("delay_while_idle", true);
}
message.put("message_id", messageId);
message.put("data", payload);
return JSONValue.toJSONString(message);
}
/**
* Creates a JSON encoded ACK message for an upstream message received from
* an application.
*
* #param to
* RegistrationId of the device who sent the upstream message.
* #param messageId
* messageId of the upstream message to be acknowledged to CCS.
* #return JSON encoded ack.
*/
public static String createJsonAck(String to, String messageId) {
Map<String, Object> message = new HashMap<String, Object>();
message.put("message_type", "ack");
message.put("to", to);
message.put("message_id", messageId);
return JSONValue.toJSONString(message);
}
/**
* Connects to GCM Cloud Connection Server using the supplied credentials.
*
* #param username
* GCM_SENDER_ID#gcm.googleapis.com
* #param password
* API Key
* #throws XMPPException
*/
public void connect(String username, String password) throws XMPPException {
config = new ConnectionConfiguration(GCM_SERVER, GCM_PORT);
config.setSecurityMode(SecurityMode.enabled);
config.setReconnectionAllowed(true);
config.setRosterLoadedAtLogin(false);
config.setSendPresence(false);
config.setSocketFactory(SSLSocketFactory.getDefault());
// NOTE: Set to true to launch a window with information about packets
// sent and received
config.setDebuggerEnabled(true);
// -Dsmack.debugEnabled=true
XMPPConnection.DEBUG_ENABLED = true;
connection = new XMPPConnection(config);
connection.connect();
connection.addConnectionListener(new ConnectionListener() {
#Override
public void reconnectionSuccessful() {
logger.info("Reconnecting..");
}
#Override
public void reconnectionFailed(Exception e) {
logger.log(Level.INFO, "Reconnection failed.. ", e);
}
#Override
public void reconnectingIn(int seconds) {
logger.log(Level.INFO, "Reconnecting in %d secs", seconds);
}
#Override
public void connectionClosedOnError(Exception e) {
logger.log(Level.INFO, "Connection closed on error.");
}
#Override
public void connectionClosed() {
logger.info("Connection closed.");
}
});
// Handle incoming packets
connection.addPacketListener(new PacketListener() {
#Override
public void processPacket(Packet packet) {
logger.log(Level.INFO, "Received: " + packet.toXML());
Message incomingMessage = (Message) packet;
GcmPacketExtension gcmPacket = (GcmPacketExtension) incomingMessage
.getExtension(GCM_NAMESPACE);
String json = gcmPacket.getJson();
try {
#SuppressWarnings("unchecked")
Map<String, Object> jsonObject = (Map<String, Object>) JSONValue
.parseWithException(json);
// present for "ack"/"nack", null otherwise
Object messageType = jsonObject.get("message_type");
if (messageType == null) {
// Normal upstream data message
handleIncomingDataMessage(jsonObject);
// Send ACK to CCS
String messageId = jsonObject.get("message_id")
.toString();
String from = jsonObject.get("from").toString();
String ack = createJsonAck(from, messageId);
send(ack);
} else if ("ack".equals(messageType.toString())) {
// Process Ack
handleAckReceipt(jsonObject);
} else if ("nack".equals(messageType.toString())) {
// Process Nack
handleNackReceipt(jsonObject);
} else {
logger.log(Level.WARNING,
"Unrecognized message type (%s)",
messageType.toString());
}
} catch (ParseException e) {
logger.log(Level.SEVERE, "Error parsing JSON " + json, e);
} catch (Exception e) {
logger.log(Level.SEVERE, "Couldn't send echo.", e);
}
}
}, new PacketTypeFilter(Message.class));
// Log all outgoing packets
connection.addPacketInterceptor(new PacketInterceptor() {
#Override
public void interceptPacket(Packet packet) {
logger.log(Level.INFO, "Sent: {0}", packet.toXML());
}
}, new PacketTypeFilter(Message.class));
connection.login(username, password);
}
public void writeToFile(String name, String regId) throws IOException {
Map<String, String> regIdMap = readFromFile();
regIdMap.put(name, regId);
PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter(
REG_ID_STORE, false)));
for (Map.Entry<String, String> entry : regIdMap.entrySet()) {
out.println(entry.getKey() + "," + entry.getValue());
}
out.println(name + "," + regId);
out.close();
}
public Map<String, String> readFromFile() {
Map<String, String> regIdMap = null;
try {
BufferedReader br = new BufferedReader(new FileReader(REG_ID_STORE));
String regIdLine = "";
regIdMap = new HashMap<String, String>();
while ((regIdLine = br.readLine()) != null) {
String[] regArr = regIdLine.split(",");
regIdMap.put(regArr[0], regArr[1]);
}
br.close();
} catch(IOException ioe) {
}
return regIdMap;
}
public static void main(String [] args) {
final String userName = "Sender ID" + "#gcm.googleapis.com";
final String password = "Server key";
SmackCcsClient ccsClient = new SmackCcsClient();
try {
ccsClient.connect(userName, password);
} catch (XMPPException e) {
e.printStackTrace();
}
}
}

How to handle multiple Authenticator

To authenticate a request, I use Authenticator.setDefault
which is VM wide...
What If I want to separate different webservices
and each one are aware of their authentication credentials.
Do I need to Authenticator.setDefault for each request ?
This may not work if there are concurrent connection with mixed webservices...

Building on Mike's response above I have the following solution, because while I much appreciate the general idea (that's why I've copied it ;-) , I see a few problems with it:
Mike's solution will throw a NullPointerException if the JDK requests the authentication via one of the two static request methods in java.net.Authenticator that do not pass the URL (then getRequestingURL() will return null).
It requires you to pass in an external regex pattern that deconstructs the URL. This is (very) easy to get wrong, and the URL class in the JDK implements this parsing, so I prefer to use that.
It requires that some external class builds the map of PasswordAuthentication objects, and then sets it. It does not implement a registration mechanism that other components in your system can use. I've also turned it into a singleton.
More of a style thing: I don't recommend duplicating class names (Authenticator), so I've renamed it DefaultAuthenticator.
Below solution I think solves these issues.
/**
* Authenticator which keeps credentials to be passed to the requestor based on authority of the requesting URL. The
* authority is <pre>user:password#host:port</pre>, where all parts are optional except the host.
* <p>
* If the configured credentials are not found, the Authenticator will use the credentials embedded in the URL, if
* present. Embedded credentials are in the form of <pre>user:password#host:port</pre>
*
* #author Michael Fortin 2011-09-23
*/
public final class DefaultAuthenticator extends Authenticator {
private static final Logger LOG = Logger.getLogger(DefaultAuthenticator.class.getName());
private static DefaultAuthenticator instance;
private Map<String, PasswordAuthentication> authInfo = new HashMap<String, PasswordAuthentication>();
private DefaultAuthenticator() {
}
public static synchronized DefaultAuthenticator getInstance() {
if (instance == null) {
instance = new DefaultAuthenticator();
Authenticator.setDefault(instance);
}
return instance;
}
// unit testing
static void reset() {
instance = null;
Authenticator.setDefault(null);
}
#Override
protected PasswordAuthentication getPasswordAuthentication() {
String requestorInfo = getRequestorInfo();
LOG.info(getRequestorType() + " at \"" + getRequestingPrompt() + "\" is requesting " + getRequestingScheme()
+ " password authentication for \"" + requestorInfo + "\"");
if (authInfo.containsKey(requestorInfo)) {
return authInfo.get(requestorInfo);
} else {
PasswordAuthentication pa = getEmbeddedCredentials(getRequestingURL());
if (pa == null) {
LOG.warning("No authentication information");
}
return pa;
}
}
/**
* Register the authentication information for a given URL.
*
* #param url - the URL that will request authorization
* #param auth - the {#link PasswordAuthentication} for this URL providing the credentials
*/
public void register(URL url, PasswordAuthentication auth) {
String requestorInfo = getRequestorInfo(url.getHost(), url.getPort());
authInfo.put(requestorInfo, auth);
}
/**
* Get the requestor info based on info provided.
*
* #param host - hostname of requestor
* #param port - TCP/IP port
* #return requestor info string
*/
private String getRequestorInfo(String host, int port) {
String fullHostname;
try {
InetAddress addr = InetAddress.getByName(host);
fullHostname = addr.getCanonicalHostName();
} catch (UnknownHostException e) {
fullHostname = host;
}
if (port == -1) {
return fullHostname;
} else {
return fullHostname + ":" + port;
}
}
/**
* Get the requestor info for the request currently being processed by this Authenticator.
*
* #return requestor info string for current request
*/
private String getRequestorInfo() {
String host;
InetAddress addr = getRequestingSite();
if (addr == null) {
host = getRequestingHost();
} else {
host = addr.getCanonicalHostName();
}
return getRequestorInfo(host, getRequestingPort());
}
/**
* Get the credentials from the requesting URL.
*
* #param url - URL to get the credentials from (can be null, method will return null)
* #return PasswordAuthentication with credentials from URL or null if URL contains no credentials or if URL is
* null itself
*/
PasswordAuthentication getEmbeddedCredentials(URL url) {
if (url == null) {
return null;
}
String userInfo = url.getUserInfo();
int colon = userInfo == null ? -1 : userInfo.indexOf(":");
if (colon == -1) {
return null;
} else {
String userName = userInfo.substring(0, colon);
String pass = userInfo.substring(colon + 1);
return new PasswordAuthentication(userName, pass.toCharArray());
}
}
}
While I'm at it, let me give you my unit tests (JUnit 4).
/**
* #author Paul Balm - May 10 2012
*/
public class DefaultAuthenticatorTest {
private static final Logger LOG = Logger.getLogger(DefaultAuthenticatorTest.class.getName());
#Before
public void setUp() throws Exception {
DefaultAuthenticator.reset();
DefaultAuthenticator.getInstance();
}
#After
public void tearDown() {
DefaultAuthenticator.reset();
}
#Test
public void testRequestAuthenticationFromURL() throws MalformedURLException, UnknownHostException {
Map<String, String[]> urls = generateURLs();
for (String urlStr : urls.keySet()) {
String[] userInfo = urls.get(urlStr);
LOG.info("Testing: " + urlStr);
URL url = new URL(urlStr);
request(userInfo[1], userInfo[2], url, true);
}
}
#Test
public void testRequestAuthenticationRegistered() throws UnknownHostException, MalformedURLException {
Map<String, String[]> urls = generateURLs();
for (String urlStr : urls.keySet()) {
String[] userInfo = urls.get(urlStr);
LOG.info("Testing: " + urlStr);
URL url = new URL(urlStr);
DefaultAuthenticator.reset();
DefaultAuthenticator auth = DefaultAuthenticator.getInstance();
String userName = userInfo[1];
String password = userInfo[2];
if (password != null) {
// You can't register a null password
auth.register(url, new PasswordAuthentication(userName, password.toCharArray()));
}
request(userName, password, url, false);
}
}
/**
* Generate a bunch of URLs mapped to String array. The String array has the following elements:
* - user info part of URL,
* - expected user,
* - expected password
*
* Note that the keys of the maps must be strings and not URL objects, because of the way URL.equals is
* implemented. This method does not consider the credentials.
*
* #throws MalformedURLException
*/
Map<String, String[]> generateURLs() {
String[] hosts = new String[]{ "127.0.0.1", "localhost.localdomain"};
List<String[]> userData = new ArrayList<String[]>();
// normal cases
userData.add(new String[] { "user:pass#", "user", "pass" }); // results in: http://user:pass#[host]
userData.add(new String[] { "", null, null });
// unexpected cases
userData.add(new String[] { "#", null, null });
userData.add(new String[] { ":#", "", "" });
userData.add(new String[] { "user:#", "user", "" });
userData.add(new String[] { ":pass#", "", "pass" });
Map<String, String[]> urls = new HashMap<String, String[]>();
for (String[] userInfo : userData) {
for (String host : hosts) {
String s = "http://" + userInfo[0] + host;
urls.put(s, userInfo);
}
}
LOG.info("" + urls.size() + " URLs prepared");
return urls;
}
private void request(String expectedUser, String expectedPass, URL url, boolean inURL)
throws UnknownHostException {
String host = url.getHost();
InetAddress addr = InetAddress.getAllByName(host)[0];
int port = url.getPort();
String protocol = url.getProtocol();
String prompt = ""; // prompt for the user when asking for the credentials
String scheme = "basic"; // or digest
RequestorType reqType = RequestorType.SERVER;
PasswordAuthentication credentials =
Authenticator.requestPasswordAuthentication(addr, port, protocol, prompt, scheme);
// If the credentials are in the URL, you can't find them using this method because we're not passing the URL
checkCredentials(url, inURL ? null : expectedUser, inURL ? null : expectedPass, credentials);
credentials = Authenticator.requestPasswordAuthentication(host, addr, port, protocol, prompt, scheme);
// If the credentials are in the URL, you can't find them using this method because we're not passing the URL
checkCredentials(url, inURL ? null : expectedUser, inURL ? null : expectedPass, credentials);
credentials = Authenticator.requestPasswordAuthentication(host, addr, port, protocol, prompt, scheme, url, reqType);
checkCredentials(url, expectedUser, expectedPass, credentials);
}
private void checkCredentials(URL url, String expectedUser, String expectedPass, PasswordAuthentication credentials) {
if (expectedUser == null) {
Assert.assertNull(url.toString(), credentials);
} else {
Assert.assertNotNull(url.toString(), credentials);
Assert.assertEquals(url.toString(), expectedUser, credentials.getUserName());
if (expectedPass == null) {
Assert.assertNull(url.toString(), credentials.getPassword());
} else {
Assert.assertArrayEquals(url.toString(), expectedPass.toCharArray(), credentials.getPassword());
}
}
}
}

Here's the solution I've implemented and it works like a charm!
import java.net.*;
import java.util.*;
import java.util.logging.*;
import java.util.regex.*;
/**
* Authenticator which keeps credentials to be passed to the requester
* based on the concatenation of the authority and the URL that requires
* authentication.
*
* If the configured credentials are not found, the Authenticator will
* use the embedded credentials if present.
*
* Embedded credentials are in the form of <pre><b>user</b>:<b>password</b><i>#host:port/<url-path></i></pre>
*
* #author Michael Fortin 2011-09-23
*/
public class Authenticator extends java.net.Authenticator {
private Logger log = Logger.getLogger(this.getClass().getName());
private Map<String, PasswordAuthentication> authInfos;
private Pattern embeddedAuthInfoPattern;
#Override
protected PasswordAuthentication getPasswordAuthentication() {
String requesterInfo = String.format("%s%s", getRequestingURL().getAuthority(), getRequestingURL().getPath());
log.fine(String.format("%s at \"%s\" is requesting %s password authentication for \"%s\"", getRequestorType(), getRequestingPrompt(), getRequestingScheme(), requesterInfo));
PasswordAuthentication pa = null;
if ((pa = authInfos.get(requesterInfo)) == null && (pa = getEmbeddedPA(getRequestingURL().getAuthority())) == null) {
log.warning(String.format("No authentication information for \"%s\"", requesterInfo));
}
return pa;
}
public void setAuthInfos(Map<String, PasswordAuthentication> authInfos) {
this.authInfos = authInfos;
}
public void setEmbeddedAuthInfoPattern(String pattern) {
this.embeddedAuthInfoPattern = Pattern.compile(pattern);
}
private PasswordAuthentication getEmbeddedPA(String authInfo) {
if (authInfo != null) {
Matcher matcher = embeddedAuthInfoPattern.matcher(authInfo);
if (matcher.find()) {
return new PasswordAuthentication(matcher.group(1), matcher.group(2).toCharArray());
}
}
return null;
}
}

Lack of answers tends to mean that nobody knows, which tells me there isn't an answer.
I've been wondering the same thing, and I think the answer is that it can't be done through java.net. I think you either need to limit your http accesses to one server at a time, or look into other packages such as org.apache.http.client.