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  • Android Java Eclipse Intent with 2 Projects

    - by user3793685
    Good day! I have 2 Projects in my Eclipse. MainActivity1 and MainActivity2 are the names of the activities. The MainActivity2 is connected to the MainActivity1 via Project in the properties of the MainActivity1. So far, I can call the package of the MainActivity2 from the MainActivity1. Now, below are my problem: I have a button in MainActivity1. What I want to do is after I click on the button in the MainActivity1, it runs the MainActivity2 project and some variables will be passed on to the MainActivity2. I've been searching in google for a while now and I couldn't get the right keyword for it. I've checked some of the questions here in StackOverflow but I'm unable to locate the problem similar to mine with calling and running the MainActivity2 class from the MainActivity1.java I'm a noob in Android Java but have knowledge in other OOP. Any tips will be a great help. Thanks

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  • Java Web Application

    - by Mark R
    I am interested in creating a simple web application that will take in user input, convert it to an XML file and send the file to a database. Coding wise I feel I am okay, it is just the general setup and what implementation to use I am a bit unsure of. At the moment I have a JSP page containing a form, the user fills out the form and on submit a get method is sent to a servlet, in the servlet doGet() method the servlet is instantiating a java object and passing it the user inputted data. The java object then writes that data to an XML file and sends it to the database via REST. All I would be interested to know is if this the standard/optimal way of creating such a web application. Any and all feedback is appreciated. Thanks

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  • Getting value in ZK by passing from java

    - by Thida
    I could not take the value that I pass from JAVA code in ZK Spreadsheet (http://www.zkoss.org) file. Here are what I am doing: In java side I call the .zul file String filenames = "test.txt"; htmlPane.setContentsURL("preview.zul?filename=" + filename); In preview.zul file < zk < zscript < ![CDATA[ System.out.println(execution.getArg().get("filename")); ]] < /zscript < zk The the result is NUll Could you help how to write the correct script? Thanks,

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  • Comparing Java enum members: == or equals() ?

    - by Bears will eat you
    I know that Java enums are compiled to classes with private constructors and a bunch of public static members. When comparing two members of a given enum, I've always used .equals(), e.g. public useEnums(SomeEnum a) { if(a.equals(SomeEnum.SOME_ENUM_VALUE)) { ... } ... } However, I just came across come code that uses the equals operator == instead: public useEnums2(SomeEnum a) { if(a == SomeEnum.SOME_ENUM_VALUE) { ... } ... } I've been programming in Java for 5+ years, and I thought I understood difference between the two - but I'm still scratching my head at which one is more correct. Which operator is the one I should be using?

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  • Java Basics: create class object

    - by user1767853
    In C++: class Rectangle { int x, y; public: void set_values (int,int); int area () {return (x*y);} }; int main () { Rectangle rect; rect.set_values (3,4); } In Java: class Rectangle { int x, y; void set_values (int x,int y); int area () {return (x*y);} } public static void main(String[] args) { Rectangle rect=new Rectangle(3,4); } In C++ compiler will create rect object & reserve memory 4 bytes. I want to know How Java is creating object?

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  • Android - doInBackground() error in AsyncTask

    - by AimanB
    What my app here basically does is it captures a photo or import from gallery, and when the Upload button is pressed, the image will be uploaded to a localhost server. Before I implemented AsyncTask into the process, it doesn't have any problem uploading whatsoever. Now that I've put AsyncTask, everything went wrong. I don't know which part that I do wrong in this phase. This is what logcat shows when I try to upload an image file: 10-28 17:23:25.989: E/AndroidRuntime(3356): FATAL EXCEPTION: AsyncTask #5 10-28 17:23:25.989: E/AndroidRuntime(3356): java.lang.RuntimeException: An error occured while executing doInBackground() 10-28 17:23:25.989: E/AndroidRuntime(3356): at android.os.AsyncTask$3.done(AsyncTask.java:299) 10-28 17:23:25.989: E/AndroidRuntime(3356): at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:352) 10-28 17:23:25.989: E/AndroidRuntime(3356): at java.util.concurrent.FutureTask.setException(FutureTask.java:219) 10-28 17:23:25.989: E/AndroidRuntime(3356): at java.util.concurrent.FutureTask.run(FutureTask.java:239) 10-28 17:23:25.989: E/AndroidRuntime(3356): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230) 10-28 17:23:25.989: E/AndroidRuntime(3356): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080) 10-28 17:23:25.989: E/AndroidRuntime(3356): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573) 10-28 17:23:25.989: E/AndroidRuntime(3356): at java.lang.Thread.run(Thread.java:856) 10-28 17:23:25.989: E/AndroidRuntime(3356): Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare() 10-28 17:23:25.989: E/AndroidRuntime(3356): at android.os.Handler.<init>(Handler.java:197) 10-28 17:23:25.989: E/AndroidRuntime(3356): at android.os.Handler.<init>(Handler.java:111) 10-28 17:23:25.989: E/AndroidRuntime(3356): at android.widget.Toast$TN.<init>(Toast.java:324) 10-28 17:23:25.989: E/AndroidRuntime(3356): at android.widget.Toast.<init>(Toast.java:91) 10-28 17:23:25.989: E/AndroidRuntime(3356): at android.widget.Toast.makeText(Toast.java:238) 10-28 17:23:25.989: E/AndroidRuntime(3356): at com.aiman.webshopper.UploadImageActivity$1execMultiPostAsync.doInBackground(UploadImageActivity.java:268) 10-28 17:23:25.989: E/AndroidRuntime(3356): at com.aiman.webshopper.UploadImageActivity$1execMultiPostAsync.doInBackground(UploadImageActivity.java:1) 10-28 17:23:25.989: E/AndroidRuntime(3356): at android.os.AsyncTask$2.call(AsyncTask.java:287) 10-28 17:23:25.989: E/AndroidRuntime(3356): at java.util.concurrent.FutureTask.run(FutureTask.java:234) This is my code for the Upload activity: public class UploadImageActivity extends Activity implements OnItemSelectedListener { InputStream inputStream; private ImageView imageView; String the_string_response; private static final int SELECT_PICTURE = 0; private static final int CAMERA_REQUEST = 1888; private static final String SERVER_UPLOAD_URI = "...myserver.php"; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_upload_image); imageView = (ImageView) findViewById(R.id.imgUpload); } public void capturePhoto(View view) { Intent cameraIntent = new Intent( android.provider.MediaStore.ACTION_IMAGE_CAPTURE); File f = new File(android.os.Environment.getExternalStorageDirectory(), "temp.jpg"); cameraIntent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(f)); startActivityForResult(cameraIntent, CAMERA_REQUEST); } public void pickPhoto(View view) { // TODO: launch the photo picker Intent intent = new Intent(); intent.setType("image/*"); intent.setAction(Intent.ACTION_GET_CONTENT); startActivityForResult(Intent.createChooser(intent, "Select Picture"), SELECT_PICTURE); } @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { super.onActivityResult(requestCode, resultCode, data); if (requestCode == CAMERA_REQUEST && resultCode == RESULT_OK) { File f = new File(Environment.getExternalStorageDirectory() .toString()); for (File temp : f.listFiles()) { if (temp.getName().equals("temp.jpg")) { f = temp; break; } } try { BitmapFactory.Options bitmapOptions = new BitmapFactory.Options(); Bitmap bitmap = BitmapFactory.decodeFile(f.getAbsolutePath(), bitmapOptions); imageView.setImageBitmap(bitmap); String path = android.os.Environment .getExternalStorageDirectory() + File.separator + "Phoenix" + File.separator + "default"; f.delete(); OutputStream outFile = null; File file = new File(path, String.valueOf(System .currentTimeMillis()) + ".jpg"); try { outFile = new FileOutputStream(file); bitmap.compress(Bitmap.CompressFormat.JPEG, 85, outFile); outFile.flush(); outFile.close(); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } catch (Exception e) { e.printStackTrace(); } } catch (Exception e) { e.printStackTrace(); } } if (requestCode == SELECT_PICTURE && resultCode == RESULT_OK) { Bitmap bitmap = getPath(data.getData()); imageView.setImageBitmap(bitmap); } } private Bitmap getPath(Uri uri) { String[] projection = { MediaStore.Images.Media.DATA }; Cursor cursor = getContentResolver().query(uri, projection, null, null, null); int column_index = cursor.getColumnIndexOrThrow(projection[0]); cursor.moveToFirst(); String filePath = cursor.getString(column_index); cursor.close(); // Convert file path into bitmap image using below line. Bitmap bitmap = BitmapFactory.decodeFile(filePath); return bitmap; } public void uploadPhoto(View view) { try { executeMultipartPost(); } catch (Exception e) { e.printStackTrace(); } } public void executeMultipartPost() throws Exception { class execMultiPostAsync extends AsyncTask<String, Void, String>{ @Override protected String doInBackground(String... params){ // Choose image here BitmapDrawable drawable = (BitmapDrawable) imageView.getDrawable(); Bitmap bitmap = drawable.getBitmap(); ByteArrayOutputStream stream = new ByteArrayOutputStream(); bitmap.compress(Bitmap.CompressFormat.JPEG, 50, stream); // compress to // which // format // you want. byte[] byte_arr = stream.toByteArray(); String image_str = Base64.encodeBytes(byte_arr); ArrayList<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(); nameValuePairs.add(new BasicNameValuePair("image", image_str)); try { HttpClient httpclient = new DefaultHttpClient(); /* * HttpPost(parameter): Server URI */ HttpPost httppost = new HttpPost(SERVER_UPLOAD_URI); httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs)); HttpResponse response = httpclient.execute(httppost); the_string_response = convertResponseToString(response); } catch (Exception e) { Toast.makeText(UploadImageActivity.this, "ERROR " + e.getMessage(), Toast.LENGTH_LONG).show(); System.out.println("Error in http connection " + e.toString()); } return the_string_response; } @Override protected void onPostExecute(String result) { super.onPostExecute(result); Toast.makeText(UploadImageActivity.this, "Response " + result, Toast.LENGTH_LONG) .show(); } public String convertResponseToString(HttpResponse response) throws IllegalStateException, IOException { String res = ""; StringBuffer buffer = new StringBuffer(); inputStream = response.getEntity().getContent(); int contentLength = (int) response.getEntity().getContentLength(); // getting // content // lengt Toast.makeText(UploadImageActivity.this, "contentLength : " + contentLength, Toast.LENGTH_LONG).show(); if (contentLength < 0) { } else { byte[] data = new byte[512]; int len = 0; try { while (-1 != (len = inputStream.read(data))) { buffer.append(new String(data, 0, len)); // converting to // string and // appending to // stringbuffer } } catch (IOException e) { e.printStackTrace(); } try { inputStream.close(); // closing the stream } catch (IOException e) { e.printStackTrace(); } res = buffer.toString(); // converting stringbuffer to string Toast.makeText(UploadImageActivity.this, "Result : " + res, Toast.LENGTH_LONG).show(); // System.out.println("Response => " + // EntityUtils.toString(response.getEntity())); } return res; } } execMultiPostAsync exec = new execMultiPostAsync(); exec.execute(); } } Can someone please check if I put the AsyncTask task correctly in this activity? I think I've made a mistake somewhere.

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  • ActiveMQ - "Cannot send, channel has already failed" every 2 seconds?

    - by quanta
    ActiveMQ 5.7.0 In the activemq.log, I'm seeing this exception every 2 seconds: 2013-11-05 13:00:52,374 | DEBUG | Transport Connection to: tcp://127.0.0.1:37501 failed: org.apache.activemq.transport.InactivityIOException: Cannot send, channel has already failed: tcp://127.0.0.1:37501 | org.apache.activemq.broker.TransportConnection.Transport | Async Exception Handler org.apache.activemq.transport.InactivityIOException: Cannot send, channel has already failed: tcp://127.0.0.1:37501 at org.apache.activemq.transport.AbstractInactivityMonitor.doOnewaySend(AbstractInactivityMonitor.java:282) at org.apache.activemq.transport.AbstractInactivityMonitor.oneway(AbstractInactivityMonitor.java:271) at org.apache.activemq.transport.TransportFilter.oneway(TransportFilter.java:85) at org.apache.activemq.transport.WireFormatNegotiator.oneway(WireFormatNegotiator.java:104) at org.apache.activemq.transport.MutexTransport.oneway(MutexTransport.java:68) at org.apache.activemq.broker.TransportConnection.dispatch(TransportConnection.java:1312) at org.apache.activemq.broker.TransportConnection.processDispatch(TransportConnection.java:838) at org.apache.activemq.broker.TransportConnection.iterate(TransportConnection.java:873) at org.apache.activemq.thread.PooledTaskRunner.runTask(PooledTaskRunner.java:129) at org.apache.activemq.thread.PooledTaskRunner$1.run(PooledTaskRunner.java:47) at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) at java.lang.Thread.run(Thread.java:662) Due to this keyword InactivityIOException, the first thing comes to my mind is InactivityMonitor, but the strange thing is MaxInactivityDuration=30000: 2013-11-05 13:11:02,672 | DEBUG | Sending: WireFormatInfo { version=9, properties={MaxFrameSize=9223372036854775807, CacheSize=1024, CacheEnabled=true, SizePrefixDisabled=false, MaxInactivityDurationInitalDelay=10000, TcpNoDelayEnabled=true, MaxInactivityDuration=30000, TightEncodingEnabled=true, StackTraceEnabled=true}, magic=[A,c,t,i,v,e,M,Q]} | org.apache.activemq.transport.WireFormatNegotiator | ActiveMQ BrokerService[localhost] Task-2 Moreover, I also didn't see something like this: No message received since last read check for ... or: Channel was inactive for too (30000) long Do a netstat, I see these connections in TIME_WAIT state: tcp 0 0 127.0.0.1:38545 127.0.0.1:61616 TIME_WAIT - tcp 0 0 127.0.0.1:38544 127.0.0.1:61616 TIME_WAIT - tcp 0 0 127.0.0.1:38522 127.0.0.1:61616 TIME_WAIT - Here're the output when running tcpdump: Internet Protocol Version 4, Src: 127.0.0.1 (127.0.0.1), Dst: 127.0.0.1 (127.0.0.1) Version: 4 Header length: 20 bytes Differentiated Services Field: 0x00 (DSCP 0x00: Default; ECN: 0x00: Not-ECT (Not ECN-Capable Transport)) 0000 00.. = Differentiated Services Codepoint: Default (0x00) .... ..00 = Explicit Congestion Notification: Not-ECT (Not ECN-Capable Transport) (0x00) Total Length: 296 Identification: 0x7b6a (31594) Flags: 0x02 (Don't Fragment) 0... .... = Reserved bit: Not set .1.. .... = Don't fragment: Set ..0. .... = More fragments: Not set Fragment offset: 0 Time to live: 64 Protocol: TCP (6) Header checksum: 0xc063 [correct] [Good: True] [Bad: False] Source: 127.0.0.1 (127.0.0.1) Destination: 127.0.0.1 (127.0.0.1) Transmission Control Protocol, Src Port: 61616 (61616), Dst Port: 54669 (54669), Seq: 1, Ack: 2, Len: 244 Source port: 61616 (61616) Destination port: 54669 (54669) [Stream index: 11] Sequence number: 1 (relative sequence number) [Next sequence number: 245 (relative sequence number)] Acknowledgement number: 2 (relative ack number) Header length: 32 bytes Flags: 0x018 (PSH, ACK) 000. .... .... = Reserved: Not set ...0 .... .... = Nonce: Not set .... 0... .... = Congestion Window Reduced (CWR): Not set .... .0.. .... = ECN-Echo: Not set .... ..0. .... = Urgent: Not set .... ...1 .... = Acknowledgement: Set .... .... 1... = Push: Set .... .... .0.. = Reset: Not set .... .... ..0. = Syn: Not set .... .... ...0 = Fin: Not set Window size value: 256 [Calculated window size: 32768] [Window size scaling factor: 128] Checksum: 0xff1c [validation disabled] [Good Checksum: False] [Bad Checksum: False] Options: (12 bytes) No-Operation (NOP) No-Operation (NOP) Timestamps: TSval 2304161892, TSecr 2304161891 Kind: Timestamp (8) Length: 10 Timestamp value: 2304161892 Timestamp echo reply: 2304161891 [SEQ/ACK analysis] [Bytes in flight: 244] Constrained Application Protocol, TID: 240, Length: 244 00.. .... = Version: 0 ..00 .... = Type: Confirmable (0) .... 0000 = Option Count: 0 Code: Unknown (0) Transaction ID: 240 Payload Content-Type: text/plain (default), Length: 240, offset: 4 Line-based text data: text/plain [truncated] \001ActiveMQ\000\000\000\t\001\000\000\000<DE>\000\000\000\t\000\fMaxFrameSize\006\177<FF><FF><FF><FF> <FF><FF><FF>\000\tCacheSize\005\000\000\004\000\000\fCacheEnabled\001\001\000\022SizePrefixDisabled\001\000\000 MaxInactivityDurationInitalDelay\006\ It is very likely a tcp port check. This is what I see when trying telnet from another host: 2013-11-05 16:12:41,071 | DEBUG | Transport Connection to: tcp://10.8.20.9:46775 failed: java.io.EOFException | org.apache.activemq.broker.TransportConnection.Transport | ActiveMQ Transport: tcp:///10.8.20.9:46775@61616 java.io.EOFException at java.io.DataInputStream.readInt(DataInputStream.java:375) at org.apache.activemq.openwire.OpenWireFormat.unmarshal(OpenWireFormat.java:275) at org.apache.activemq.transport.tcp.TcpTransport.readCommand(TcpTransport.java:229) at org.apache.activemq.transport.tcp.TcpTransport.doRun(TcpTransport.java:221) at org.apache.activemq.transport.tcp.TcpTransport.run(TcpTransport.java:204) at java.lang.Thread.run(Thread.java:662) 2013-11-05 16:12:41,071 | DEBUG | Transport Connection to: tcp://10.8.20.9:46775 failed: org.apache.activemq.transport.InactivityIOException: Cannot send, channel has already failed: tcp://10.8.20.9:46775 | org.apache.activemq.broker.TransportConnection.Transport | Async Exception Handler org.apache.activemq.transport.InactivityIOException: Cannot send, channel has already failed: tcp://10.8.20.9:46775 at org.apache.activemq.transport.AbstractInactivityMonitor.doOnewaySend(AbstractInactivityMonitor.java:282) at org.apache.activemq.transport.AbstractInactivityMonitor.oneway(AbstractInactivityMonitor.java:271) at org.apache.activemq.transport.TransportFilter.oneway(TransportFilter.java:85) at org.apache.activemq.transport.WireFormatNegotiator.oneway(WireFormatNegotiator.java:104) at org.apache.activemq.transport.MutexTransport.oneway(MutexTransport.java:68) at org.apache.activemq.broker.TransportConnection.dispatch(TransportConnection.java:1312) at org.apache.activemq.broker.TransportConnection.processDispatch(TransportConnection.java:838) at org.apache.activemq.broker.TransportConnection.iterate(TransportConnection.java:873) at org.apache.activemq.thread.PooledTaskRunner.runTask(PooledTaskRunner.java:129) at org.apache.activemq.thread.PooledTaskRunner$1.run(PooledTaskRunner.java:47) at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) at java.lang.Thread.run(Thread.java:662) 2013-11-05 16:12:41,071 | DEBUG | Unregistering MBean org.apache.activemq:BrokerName=localhost,Type=Connection,ConnectorName=ope nwire,ViewType=address,Name=tcp_//10.8.20.9_46775 | org.apache.activemq.broker.jmx.ManagementContext | ActiveMQ Transport: tcp:/ //10.8.20.9:46775@61616 2013-11-05 16:12:41,073 | DEBUG | Stopping connection: tcp://10.8.20.9:46775 | org.apache.activemq.broker.TransportConnection | ActiveMQ BrokerService[localhost] Task-5 2013-11-05 16:12:41,073 | DEBUG | Stopping transport tcp:///10.8.20.9:46775@61616 | org.apache.activemq.transport.tcp.TcpTranspo rt | ActiveMQ BrokerService[localhost] Task-5 2013-11-05 16:12:41,073 | DEBUG | Initialized TaskRunnerFactory[ActiveMQ Task] using ExecutorService: java.util.concurrent.Threa dPoolExecutor@23cc2a28 | org.apache.activemq.thread.TaskRunnerFactory | ActiveMQ BrokerService[localhost] Task-5 2013-11-05 16:12:41,074 | DEBUG | Closed socket Socket[addr=/10.8.20.9,port=46775,localport=61616] | org.apache.activemq.transpo rt.tcp.TcpTransport | ActiveMQ Task-1 2013-11-05 16:12:41,074 | DEBUG | Forcing shutdown of ExecutorService: java.util.concurrent.ThreadPoolExecutor@23cc2a28 | org.apache.activemq.util.ThreadPoolUtils | ActiveMQ BrokerService[localhost] Task-5 2013-11-05 16:12:41,074 | DEBUG | Stopped transport: tcp://10.8.20.9:46775 | org.apache.activemq.broker.TransportConnection | ActiveMQ BrokerService[localhost] Task-5 2013-11-05 16:12:41,074 | DEBUG | Connection Stopped: tcp://10.8.20.9:46775 | org.apache.activemq.broker.TransportConnection | ActiveMQ BrokerService[localhost] Task-5 2013-11-05 16:12:41,902 | DEBUG | Sending: WireFormatInfo { version=9, properties={MaxFrameSize=9223372036854775807, CacheSize=1024, CacheEnabled=true, SizePrefixDisabled=false, MaxInactivityDurationInitalDelay=10000, TcpNoDelayEnabled=true, MaxInactivityDuration=30000, TightEncodingEnabled=true, StackTraceEnabled=true}, magic=[A,c,t,i,v,e,M,Q]} | org.apache.activemq.transport.WireFormatNegotiator | ActiveMQ BrokerService[localhost] Task-5 So the question is: how can I find out the process that is trying to connect to my ActiveMQ (from localhost) every 2 seconds?

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  • What's the proper way to setup different objects as delegates using Interface Builder?

    - by eagle
    Let's say I create a new project. I now add two text fields to the view controller in Interface Builder. I want to respond to delegate events that the text fields create, however, I don't want to have the main view controller to act as the delegate for both text fields. Ideally I want a separate file for each text field that acts as the delegate. Each of these objects also needs to be able to interact with the main view controller. My question is how I would set this up and link everything correctly? I tried creating a new class that inherits from NSObject and implements UITextFieldDelegate. I then added an instance variable called "viewController" of the same type of my view controller and marked it with IBOutlet (this required me to add #import "myViewcontroller.h"). I then went to Interface Builder and opened up my view controller which contains the two edit boxes. I added an NSObject to the form and changed it's type to be of the new class I created. I set its viewController property to the File's Owner, and set one of the textbox's delegate properties to point to this new object I created. Now when I run the program, it crashes when I touch the text box. It gives the error EXC_BAD_ACCESS. I'm guessing I didn't link stuff correctly in IB. Some things I'm not sure about which might be the problem: Does IB automatically know to create an instance of the class just by placing the NSObject in the ViewController? Can it properly assign the viewController property to an instance of itself even though it is creating itself at the same time?

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  • When using Data Annotations with MVC, Pro and Cons of using an interface vs. a MetadataType

    - by SkippyFire
    If you read this article on Validation with the Data Annotation Validators, it shows that you can use the MetadataType attribute to add validation attributes to properties on partial classes. You use this when working with ORMs like LINQ to SQL, Entity Framework, or Subsonic. Then you can use the "automagic" client and server side validation. It plays very nicely with MVC. However, a colleague of mine used an interface to accomplish exactly the same result. it looks almost exactly the same, and functionally accomplishes the same thing. So instead of doing this: [MetadataType(typeof(MovieMetaData))] public partial class Movie { } public class MovieMetaData { [Required] public object Title { get; set; } [Required] [StringLength(5)] public object Director { get; set; } [DisplayName("Date Released")] [Required] public object DateReleased { get; set; } } He did this: public partial class Movie :IMovie { } public interface IMovie { [Required] object Title { get; set; } [Required] [StringLength(5)] object Director { get; set; } [DisplayName("Date Released")] [Required] object DateReleased { get; set; } } So my question is, when does this difference actually matter? My thoughts are that interfaces tend to be more "reusable", and that making one for just a single class doesn't make that much sense. You could also argue that you could design your classes and interfaces in a way that allows you to use interfaces on multiple objects, but I feel like that is trying to fit your models into something else, when they should really stand on their own. What do you think?

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  • make local only daemon listening on different interface (using iptables port forwarding)?

    - by UniIsland
    i have a daemon program which listens on 127.0.0.1:8000. i need to access it when i connect to my box with vpn. so i want it to listen on the ppp0 interface too. i've tried the "ssh -L" method. it works, but i don't think it's the right way to do that, having an extra ssh process running in the background. i tried the "netcat" method. it exits when the connection is closed. so not a valid way for "listening". i also tried several iptables rules. none of them worked. i'm not listing here all the rules i've used. iptables -A FORWARD -j ACCEPT iptables -t nat -A PREROUTING -i ppp+ -p tcp --dport 8000 -j DNAT --to-destination 127.0.0.1:8000 the above ruleset doesn't work. i have net.ipv4.ip_forward set to 1. anyone knows how to redirect traffic from ppp interface to lo? say, listen on "192.168.45.1:8000 (ppp0)" as well as "127.0.0.1:8000 (lo)" there's no need to alter the port. thanx

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  • Is there anything like Unity for simple things that don't require an interface?

    - by Dave
    Perhaps I'm misapplying Unity, but here goes. I have a couple of applications, both of which load the same plugin assemblies. All assemblies require a library, and I want them to be able to access this library via Unity. However, in order to use Unity, or any other IoC framework, I'd have to write an interface for this library. I will probably do this, but since an interface isn't really needed for anything other than to support Unity, I am afraid that this means that I am 1) missing the point, or 2) misapplying the framework. If I avoid something that offers me DI, then I'd have to make the library class a singleton, and then pass it to all of the plugin constructors, or via a public property, and I don't want to do this. That said, and without actually implementing anything with Unity yet, I'm not getting one other detail -- although Unity will let me request the library via Resolve<, my plugins will still need to have a reference to the Unity instance that is created in the main applications. So is this a case where your only option is to pass the Unity reference to all of the plugins, but then it's convenient from that point on, merely because you can use Unity to get at all of the other dependencies?

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  • What would be the safest way to store objects of classes derived from a common interface in a common

    - by Svenstaro
    I'd like to manage a bunch of objects of classes derived from a shared interface class in a common container. To illustrate the problem, let's say I'm building a game which will contain different actors. Let's call the interface IActor and derive Enemy and Civilian from it. Now, the idea is to have my game main loop be able to do this: // somewhere during init std::vector<IActor> ActorList; Enemy EvilGuy; Civilian CoolGuy; ActorList.push_back(EvilGuy); ActorList.push_back(CoolGuy); and // main loop while(!done) { BOOST_FOREACH(IActor CurrentActor, ActorList) { CurrentActor.Update(); CurrentActor.Draw(); } } ... or something along those lines. This example obviously won't work but that is pretty much the reason I'm asking here. I'd like to know: What would be the best, safest, highest-level way to manage those objects in a common heterogeneous container? I know about a variety of approaches (Boost::Any, void*, handler class with boost::shared_ptr, Boost.Pointer Container, dynamic_cast) but I can't decide which would be the way to go here. Also I'd like to emphasize that I want to stay away as far as possible from manual memory management or nested pointers. Help much appreciated :).

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  • simple Java "service provider frameworks"?

    - by Jason S
    I refer to "service provider framework" as discussed in Chapter 2 of Effective Java, which seems like exactly the right way to handle a problem I am having, where I need to instantiate one of several classes at runtime, based on a String to select which service, and an Configuration object (essentially an XML snippet): But how do I get the individual service providers (e.g. a bunch of default providers + some custom providers) to register themselves? interface FooAlgorithm { /* methods particular to this class of algorithms */ } interface FooAlgorithmProvider { public FooAlgorithm getAlgorithm(Configuration c); } class FooAlgorithmRegistry { private FooAlgorithmRegistry() {} static private final Map<String, FooAlgorithmProvider> directory = new HashMap<String, FooAlgorithmProvider>(); static public FooAlgorithmProvider getProvider(String name) { return directory.get(serviceName); } static public boolean registerProvider(String name, FooAlgorithmProvider provider) { if (directory.containsKey(name)) return false; directory.put(name, provider); return true; } } e.g. if I write custom classes MyFooAlgorithm and MyFooAlgorithmProvider to implement FooAlgorithm, and I distribute them in a jar, is there any way to get registerProvider to be called automatically, or will my client programs that use the algorithm have to explicitly call FooAlgorithmRegistry.registerProvider() for each class they want to use?

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  • Free utility which runs in Linux to create a UML class diagram from Java source files

    - by DeletedAccount
    I prefer to jot down UML-diagrams on paper and then implement them using Java. It would be nice to have a utility which could create UML-diagrams for me which I may share on-line and include in the digital documentation. In other words: I want to create UML diagrams from Java source code. The utility must be able to: Run in Linux. Handle Generics, i.e show List<Foo correctly in parameters and return type. Show class inheritance and interface implementations. It's nice if the utility is able to: Run in Windows and Mac OS X. Display enums in some nice manner. Generate output in a diagram format which I may modify using some other utility. Run from the command line. Restrict the UML generation to a set of packages which I may specify. Handle classes/interfaces which are not part of my source code. It could include the first class/interface which is external in the UML diagram. Perhaps in another color to indicate it being a library/framework created by someone else. Focuses on this task and doesn't try to solve the whole issue of documentation.

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  • How to Implement an Interface that Requires Duplicate Member Names?

    - by Will Marcouiller
    I often have to implement some interfaces such as IEnumerable<T> in my code. Each time, when implementing automatically, I encounter the following: public IEnumerator<T> GetEnumerator() { // Code here... } public IEnumerator GetEnumerator1() { // Code here... } Though I have to implement both GetEnumerator() methods, they impossibly can have the same name, even if we understand that they do the same, somehow. The compiler can't treat them as one being the overload of the other, because only the return type differs. When doing so, I manage to set the GetEnumerator1() accessor to private. This way, the compiler doesn't complaint about not implementing the interface member, and I simply throw a NotImplementedException within the method's body. However, I wonder whether it is a good practice, or if I shall proceed differently, as perhaps a method alias or something like so. What is the best approach while implementing an interface such as IEnumerable<T> that requires the implementation of two different methods with the same name? EDIT #1 Does VB.NET reacts differently from C# while implementing interfaces, since in VB.NET it is explicitly implemented, thus forcing the GetEnumerator1(). Here's the code: Public Function GetEnumerator() As System.Collections.Generic.IEnumerator(Of T) Implements System.Collections.Generic.IEnumerable(Of T).GetEnumerator // Code here... End Function Public Function GetEnumerator1() As System.Collections.Generic.IEnumerator Implements System.Collections.Generic.IEnumerable.GetEnumerator // Code here... End Function Both GetEnumerator() methods are explicitly implemented, and the compile will refuse them to have the same name. Why?

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  • Java Generic Type and Reflection

    - by Tom Tucker
    I have some tricky generic type problem involving reflection. Here's the code. public @interface MyConstraint { Class<? extends MyConstraintValidator<?>> validatedBy(); } public interface MyConstraintValidator<T extends Annotation> { void initialize(T annotation); } /** @param annotation is annotated with MyConstraint. */ public void run(Annotation annotation) { Class<? extends MyConstraintValidator<? extends Annotation>> validatorClass = annotation.annotationType().getAnnotation(MyConstraint.class).validatedBy(); validatorClass.newInstance().initialize(annotation) // will not compile! } The run() method above will not compile because of the following error. The method initialize(capture#10-of ? extends Annotation) in the type MyConstraintValidator<capture#10-of ? extends Annotation> is not applicable for the arguments (Annotation) If I remove the wild cards, then it compiles and works fine. What would be the propert way to declare the type parameter for the vairable validatorClass? Thanks.

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  • How to Implement an Interface that Requires Duplicate Member Names in C#?

    - by Will Marcouiller
    I often have to implement some interfaces such as IEnumerable<T> in my code. Each time, when implementing automatically, I encounter the following: public IEnumerator<T> GetEnumerator() { // Code here... } public IEnumerator GetEnumerator1() { // Code here... } Though I have to implement both GetEnumerator() methods, they impossibly can have the same name, even if we understand that they do the same, somehow. The compiler can't treat them as one being the overload of the other, because only the return type differs. When doing so, I manage to set the GetEnumerator1() accessor to private. This way, the compiler doesn't complaint about not implementing the interface member, and I simply throw a NotImplementedException within the methods body. However, I wonder whether it is a good practice, or if I shall proceed differently, as perhaps a method alias or something like so. What is the best approach while implementing an interface such as IEnumerable<T> that requires the implementation of two different methods with the same name?

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  • Is it advisable to have an interface as the return type?

    - by wb
    I have a set of classes with the same functions but with different logic. However, each class function can return a number of objects. It is safe to set the return type as the interface? Each class (all using the same interface) is doing this with different business logic. protected IMessage validateReturnType; <-- This is in an abstract class public bool IsValid() <-- This is in an abstract class { return (validateReturnType.GetType() == typeof(Success)); } public IMessage Validate() { if (name.Length < 5) { validateReturnType = new Error("Name must be 5 characters or greater."); } else { validateReturnType = new Success("Name is valid."); } return validateReturnType; } Are there any pitfalls with unit testing the return type of an function? Also, is it considered bad design to have functions needing to be run in order for them to succeed? In this example, Validate() would have to be run before IsValid() or else IsValid() would always return false. Thank you.

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  • C# What is the best way to determine the type of an inherited interface class?

    - by Martijn
    In my application I work with criterias. I have one base Criteria interface and and other interfaces who inherits from this base interface: ICriteria | | ---------------------- | | ITextCriteria IChoices What I'd like to know is, what is the best way to know what Type the class is? In my code I have a dropdown box and based on that I have to determine the type: // Get selected criteria var selectedCriteria = cmbType.SelectedItem as ICriteria; if (selectedCriteria is IChoices) { //selectedCriteria = cmbType.SelectedItem as IChoices; Doesn't work IChoices criteria = selectedCriteria as IChoices;//cmbType.SelectedItem as IChoices; SaveMultipleChoiceValues(criteria); //_category.AddCriteria(criteria); } else { //ICriteria criteria = selectedCriteria; //cmbType.SelectedItem as ICriteria; if (selectedCriteria.GetCriteriaType() == CriteriaTypes.None) { return; } //_category.AddCriteria(criteria); } _category.AddCriteria(selectedCriteria); selectedCriteria.LabelText = txtLabeltext.Text; this.Close(); My question is, is this the best way? Or is there a better way to achieve this? The chance is big that there are coming more interfaces based on ICriteria.

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  • java packets byte

    - by user303289
    Guys, I am implementing a protocol in one of the wireless project. I am stucked at one point. In of the java file i am suppose to receive a packet and that packet is 12 byte packet and I have to write different functions for reading different parts of packets and convert it to diferent type. Like I want first four byte in one of the function and convert it to int, next two bytes in string. and again next two in string, last two hop in string and followed by last two int. I want follwing function to implement: // here is the interface /* FloodingData should use methods defined in this class. */ class FloodingPacket{ public static void main(String arg[]){ byte FloodingPack[]; // just for example to test in code FloodingPack=new byte[12]; interface IFloodingPacket { // Returns the unique sequence number for the packet int getSequenceNumber() ; // Returns the source address for the packet String getSourceAddress(); // Returns the destination address for the packet String getDestinationAddress(); // Returns the last hop address for the packet String getLastHopAddress(); // Sets the last hop address to the address of the node // which the packet was received from void updateLastHopAddress(); // Returns the entire packet in bytes (for sending) byte[] getBytes(); // Sets the bytes of the packet (for receiving) void setBytes(byte[] packet); }

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  • Combining HBase and HDFS results in Exception in makeDirOnFileSystem

    - by utrecht
    Introduction An attempt to combine HBase and HDFS results in the following: 2014-06-09 00:15:14,777 WARN org.apache.hadoop.hbase.HBaseFileSystem: Create Dir ectory, retries exhausted 2014-06-09 00:15:14,780 FATAL org.apache.hadoop.hbase.master.HMaster: Unhandled exception. Starting shutdown. java.io.IOException: Exception in makeDirOnFileSystem at org.apache.hadoop.hbase.HBaseFileSystem.makeDirOnFileSystem(HBaseFile System.java:136) at org.apache.hadoop.hbase.master.MasterFileSystem.checkRootDir(MasterFi leSystem.java:428) at org.apache.hadoop.hbase.master.MasterFileSystem.createInitialFileSyst emLayout(MasterFileSystem.java:148) at org.apache.hadoop.hbase.master.MasterFileSystem.<init>(MasterFileSyst em.java:133) at org.apache.hadoop.hbase.master.HMaster.finishInitialization(HMaster.j ava:572) at org.apache.hadoop.hbase.master.HMaster.run(HMaster.java:432) at java.lang.Thread.run(Thread.java:744) Caused by: org.apache.hadoop.security.AccessControlException: Permission denied: user=hbase, access=WRITE, inode="/":vagrant:supergroup:drwxr-xr-x at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.check(FSPe rmissionChecker.java:224) at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.check(FSPe rmissionChecker.java:204) at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.checkPermi ssion(FSPermissionChecker.java:149) at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.checkPermission(F SNamesystem.java:4891) at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.checkPermission(F SNamesystem.java:4873) at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.checkAncestorAcce ss(FSNamesystem.java:4847) at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.mkdirsInternal(FS Namesystem.java:3192) at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.mkdirsInt(FSNames ystem.java:3156) at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.mkdirs(FSNamesyst em.java:3137) at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.mkdirs(NameN odeRpcServer.java:669) at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTra nslatorPB.mkdirs(ClientNamenodeProtocolServerSideTranslatorPB.java:419) at org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos$Cl ientNamenodeProtocol$2.callBlockingMethod(ClientNamenodeProtocolProtos.java:4497 0) at org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.cal l(ProtobufRpcEngine.java:453) at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:1002) at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:1752) at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:1748) at java.security.AccessController.doPrivileged(Native Method) at javax.security.auth.Subject.doAs(Subject.java:422) at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInforma tion.java:1438) at org.apache.hadoop.ipc.Server$Handler.run(Server.java:1746) at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstruct orAccessorImpl.java:62) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingC onstructorAccessorImpl.java:45) at java.lang.reflect.Constructor.newInstance(Constructor.java:408) at org.apache.hadoop.ipc.RemoteException.instantiateException(RemoteExce ption.java:90) at org.apache.hadoop.ipc.RemoteException.unwrapRemoteException(RemoteExc eption.java:57) at org.apache.hadoop.hdfs.DFSClient.primitiveMkdir(DFSClient.java:2153) at org.apache.hadoop.hdfs.DFSClient.mkdirs(DFSClient.java:2122) at org.apache.hadoop.hdfs.DistributedFileSystem.mkdirs(DistributedFileSy stem.java:545) at org.apache.hadoop.fs.FileSystem.mkdirs(FileSystem.java:1915) at org.apache.hadoop.hbase.HBaseFileSystem.makeDirOnFileSystem(HBaseFile System.java:129) ... 6 more while configuration and system settings are as follows: [vagrant@localhost hadoop-hdfs]$ hadoop fs -ls hdfs://localhost/ Found 1 items -rw-r--r-- 3 vagrant supergroup 1010827264 2014-06-08 19:01 hdfs://localhost/u buntu-14.04-desktop-amd64.iso [vagrant@localhost hadoop-hdfs]$ /etc/hadoop/conf/core-site.xml <configuration> <property> <name>fs.defaultFS</name> <value>hdfs://localhost:8020</value> </property> </configuration> /etc/hbase/conf/hbase-site.xml <configuration> <property> <name>hbase.rootdir</name> <value>hdfs://localhost:8020/hbase</value> </property> <property> <name>hbase.cluster.distributed</name> <value>true</value> </property> </configuration> /etc/hadoop/conf/hdfs-site.xml <configuration> <property> <name>dfs.name.dir</name> <value>/var/lib/hadoop-hdfs/cache</value> </property> <property> <name>dfs.data.dir</name> <value>/tmp/hellodatanode</value> </property> </configuration> NameNode directory permissions [vagrant@localhost hadoop-hdfs]$ ls -ltr /var/lib/hadoop-hdfs/cache total 8 -rwxrwxrwx. 1 hbase hdfs 15 Jun 8 23:43 in_use.lock drwxrwxrwx. 2 hbase hdfs 4096 Jun 8 23:43 current [vagrant@localhost hadoop-hdfs]$ HMaster is able to start if fs.defaultFS property has been commented in core-site.xml NameNode is listening [vagrant@localhost hadoop-hdfs]$ netstat -nato | grep 50070 tcp 0 0 0.0.0.0:50070 0.0.0.0:* LIST EN off (0.00/0/0) tcp 0 0 33.33.33.33:50070 33.33.33.1:57493 ESTA BLISHED off (0.00/0/0) and accessible by navigating to http://33.33.33.33:50070/dfshealth.jsp. Question How to solve makeDirOnFileSystem exception and let HBase connect to HDFS?

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  • Gilda Garretón, a Java Developer and Parallelism Computing Researcher

    - by Yolande
    In a new interview titled “Gilda Garretón, a Java Developer and Parallelism Computing Research,” Garretón shares her first-hand experience developing with Java and Java 7 for very large-scale integration (VLSI) of computer-aided design (CAD). Garretón gives an insightful overview of how Java is contributing to the parallelism development and to the Electric VLSI Design Systems, an open source VLSI CAD application used as a research platform for new CAD algorithms as well as the research flow for hardware test chips.  Garretón considers that parallelism programming is hard and complex, yet important developments are taking place.  "With the addition of the concurrent package in Java SE 6 and the Fork/Join feature in Java SE 7, developers have a chance to rely more on existing frameworks and dedicate more time to the essence of their parallel algorithms." Read the full article here  

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