Develop Reference

How to send from JAVA String(path of file) to C?

i want to send from java some paths to C.
For example i have a folder that have 4 subfoldes... From java i read the length of them from the code below and it returns me 4.
public static int GetLength(){File file = new File("C:\\Registrations");
File[] files = file.listFiles(new FileFilter(){
public boolean accept(File f) {
return f.isDirectory(); }});
return files.length;} }
Now with a thread i start to call the function that connect with C
public Start(){ Thread listeningThread = new Thread(new Runnable(){
public void run(){
new Match(GetDBNumber()); } });
listeningThread.start();}
So far all good. Now from MATCH(int x) class i want to call a C code and every time give the path of the Main folder each time
*PSEUDOCODE* public class Match {
public Match( int len){
System.out.println("subfolders : "+len);
for (i=0; i<len; i++)
{ //Some way call C programm (like an exe)
//with the first,second,third,fourth path
}
.... }
The C code that will recieve the path will be look like that...
int main() {
FILE *fp = fopen(FilePATH, "r");
......
......
return 0; }
I try with ProcessBuilder but i cant send the path every time with this way...
ProcessBuilder p = new ProcessBuilder();
//receive.exe is the exe that Codeblocks create after built the C code
p.command("C:\\Users\\PC\\Documents\\NetBeansProjects\\TEST\\C\\recieve.exe");
try {
p.start();
} catch (Exception e) {System.out.println("Error");
}

As stated by Eric Fitzsimmons,
you will need to use JNI to pass a String value from Java to C.
The C part will need to be in a dll that is available to the Java program.
Wikipedia has a JNI article
Oracle has an in-depth JNI write-up
Edit Concerning JNI.
If you want to send a value between Java and C,
there are only a few ways to do it.
JNI. As stated, Java Native Interface is built for this. This seems to be the best solution.
Use an external Data store. Write something to a data store (maybe a file or a database) on one side and read it on the other side (sides being Java and C).
Write a stand-alone C program that writes to standard out. Launch that program from within Java. Read what was written in java. This is not a great idea.

Depends on a lot of variables. I'll assume that you are building the C code and can change how things are passed, so...
Easiest to hardest:
Pass it in as a command line parameter (only works once per C file execution)
Write/update a text file on your hard drive that the C program can watch
Use TCP/IP and send messages over a pre-designated socket
Build as a shared library or DLL and Use JNI to call the C functions
If you were doing this professionally and this was just the beginning of a larger development effort you'd be wise to look into more professional tooling:
a message bus (Apache has one called ActiveMQ) is designed to do exactly what you are trying to do (and so much more)
a shared cache (Hazlecast can connect Java to C++ and nearly everything else and share data freely)
A shared table in a database that both languages can access.
These are much higher initial investment in time (otherwise free) but they have innumerable features that you could continue to take advantage of as your system grows.

Use jni (Java native interfaces) Make a c++ .dll file and you can easily pass information between both languages.
Good example/explanation for using jni:
https://www3.ntu.edu.sg/home/ehchua/programming/java/JavaNativeInterface.html

Use code generation for executing generic tests

I think I have an interesting question and PERHAPS there is already the answer which is still a secret for me, so I hope to get some helps from expers. :)
So here is the thing:
I work for the test/validation team to test our Java API and basically my job is to follow test plan and write the test code. After writing that for more than two months, I find the codes are really similar. For example:
To test function could return expected result or throw exception correctly, we may need write several .java to run.
1.java set up server connection, connect client and send request, initiate variables with correct values and pass them to the function A, catch the answer and analyse it
2.java set up server connection, connect client and send request, initiate all variables with correct values but one with bad value and pass them to function A, catch the answer and analyse it
3.java set up server connection, connect client and send request, initiate all variables with correct values but two with bad values and pass them to function A, catch the answer and analyse it
so you see in three java test files, the most part of them are the same or similar enough and even copy/paste make the job boring and possible to be wrong.
I wonder whether or not I could define test code corresponding different behavior, then for every test java file, I define a text including the behavior and then a mother class who is in charge of loading the text file and assembling the final test java file according to the text file?
Like this:
Text File:
1) set up server
2) connect client
3) send request
4) initiate variables with correct values
5) initiate variables with correct values but one with bad value
6) initiate variables with correct values but two with bad values
7) catch the result and analyse it
Mother.java
1) load Text file
2) create a son.java
3) find the code corresponding the Text file and write them to son.java
Then the coder open son.java at IDE to check syntax, or import or anything conflict then run it.
Is my idea realizable or not? Is there already something similar?
Any information would be appreciated, thanks a millions in advance!

Honestly, this does not sound like a good use case for code generation. Instead of generating a class for each test case, you should implement a more general testing utility which takes the required input as its data and executes the generic testing code based on this data.
From what you write, this would for example be something like a simple base class for a JUnit test:
abstract class AbstractServerDependantTest {
protected Server server;
protected Client client;
#Before
public void setUp() {
server = new Server();
server.start();
client = new Client();
client.connectTo(server);
}
#After
public void tearDpwm() {
client.disconnect();
server.shutDown();
}
}
Now you can write three test classes which inherit from this AbstractServerDependantTest without copy pasting your code.

How to run vbscript function from java?

From java code i am able to run the vbscript by using this code
Runtime.getRuntime().exec("wscript C:\\ppt\\test1.vbs ");
But want to know how to call the method of vbscript from java..for example in test1.vbs
Set objPPT = CreateObject("PowerPoint.Application")
objPPT.Visible = True
Set objPresentation = objPPT.Presentations.Open("C:\ppt\Labo.ppt")
Set objSlideShow = objPresentation.SlideShowSettings.Run.View
sub ssn1()
objPPT.Run "C:\ppt\Labo.ppt!.SSN"
End sub
how to call only ssn1() method from java.Otherwise can we run the macro of a power point from java code..kindly help!!

This should make you happy :) Go to the WScript section : http://technet.microsoft.com/library/ee156618.aspx
Here's my idea... in your vbscript file, make your script listen to a command line parameter that would specify which method to call. Then, in Java, you could only have to use this parameter whenever you want to call a specific method in the file.
Otherwise, if you want to access powerpoint in java, you will need to access its API like you did in vbscript, which is possible if vbscript can do it but the approach / syntax may change.

I'm not so much into the visual basic script side, but if you can expose your visual basic script as a COM object, the you can access the methods of it from java by usage of frameworks such as for example com4j:
http://com4j.java.net/

The PowerPoint application object's .Run method lets you call any public subroutine or function in any open presentation or loaded add-in

This post answers the OP's question:
Otherwise can we run the macro of a power point from java code..kindly help!!
(but does not address the original vbscript question)
There's the JACOB library, which stands for Java COM Bridge, you can find here: http://sourceforge.net/projects/jacob-project/?source=directory
With it you can invoke Excel, Word, Outlook, PowerPoint application object model methods.
I've tried this with Excel but not PowerPoint. (This is just some sample code, one might want to make it more object oriented.)
public class Excel {
private static ActiveXComponent xl = null;
public static Init() {
try {
ComThread.InitSTA();
xl = ActiveXComponent.connectToActiveInstance("Excel.Application.14");
// 14 is Office 2010, if you don't know what version you can do "Excel.Application"
if (xl==null) {
// code to launch Excel if not running:
xl = new ActiveXComponent("Excel.Application");
Dispatch.put(xl, "Visible", Constants.kTrue);
}
}
catch (Exception e) {
ComThread.Release();
}
}
public static String Run(String vbName) {
// Variant v = Dispatch.call(xl, "Run", vbName); // using string name lookup
Variant v = Dispatch.call(xl, 0x103, vbName); // using COM offset
// return Dispatch.get(this, "Name").getString();
return v.getString();
}
public static Variant Run1p(String vbName, Object param) {
// Variant v = Dispatch.call(xl, "Run", vbName, param);
return Dispatch.call(xl, 0x103, vbName, param);
// return Dispatch.get(this, "Name").getString();
}
public static Worksheet GetActiveWorksheet () {
// Dispatch d = xl.getProperty("ActiveSheet").toDispatch();
Dispatch d = Dispatch.get(xl, 0x133).toDispatch ();
return d; // you may want to put a wrapper around this...
}
}
Notes:
For Excel, at least, to get Run to invoke a VBA macro/subroutine several things have to be true:
The Excel workbook containing the macro must be "Active" (i.e. must
be the ActiveWorkbook) otherwise Run will not find the VBA subroutine. (However the workbook does not have to be
screen visible!! This means you can call a VBA Macro that is in an add-in!).
You can then pass the name of the macro using the following syntax as a string literal:
VBAProjectName.VBAModuleName.SubroutineName
For COM object invocations, you can use the name lookup version or the id number version. The id numbers come from the published COM interfaces (which you can find in C++ header files, or possibly have JACOB look them up for you).
If you successfully did the connection to Excel, be sure to call ComThread.Release() when you're done. Put it in some appropriately surrounding finally. If the process of your Java code terminates without calling it, the COM reference count on Excel will be wrong, and the Excel process will never terminate, even after you exit the Excel application. Once that happens, needless to say, Excel starts to behave screwy then (when you try to use it next, it runs but will fail to load any plug-ins/add-ons). If that happens (as it can during debugging esp. if you are bypassing finally's for better debugging) you have to use the task manager to kill the Excel process.

Notification when file download completes in Play framework

I'm successfully using Play 1.2.4 to serve large binary file downloads to users using the renderBinary() method.
I'd like to have a hint of when the user actually completes the download. Generally speaking, I know this is somewhat possible as I've done it before. In an old version of my website, I wrote a simple servlet that served up binary file downloads. Once that servlet finished writing out the contents of the file, a notification was sent. Certainly not perfect, but useful nonetheless. In my testing, it did provide an indication of how long the user took to download a file.
Reviewing the Play source, I see that the play.mvc.results.RenderBinary class has a handy apply() method that I could use. I wrote my own version of RenderBinary so I could send the notification after the apply() method finished writing out the file contents.
The problem I found is that calls to response.out.write() obviously cache the outgoing bytes (via Netty?), so even though I am writing out several megabytes of data, the calls to play.mvc.Http.Response.out.write() complete in seconds, even though it takes the downloader a couple minutes to download the file.
I don't mind writing custom classes, although I'd prefer to use a stock Play 1.2.4 distribution.
Any ideas on how to get a notification of when the end of a file download is pushed out towards the user's browser?

It seems this may help you, as it tackles a somehow similar problem:
Detect when browser receives file download
I'm not sure you'll eb able to do it via renderBinary nor an #After annotation in the controller. Some browser-side detection of the download and then a notification to the server (pinging the download's end) would work.
There may be an alternative: using WebSockets (streaming the file via the socket and then having teh client to answer) but it may be overkill for this :)

you can use ArchivedEventStream.
first create a serializable ArcivedEventStream class..
public class Stream<String> extends ArchivedEventStream<String> implements Serializable{
public Stream(int arg0) {
super(arg0);
}
}
then on your controller...
public static void downloadPage(){
Stream<String> userStream = Cache.get(session.getId(),Stream.class);
if( userStream == null){
userStream = new Stream<String>(5);
Cache.add(session.getId(), userStream);
}
render();
}
public static void download(){
await(10000);// to provide some latency. actually no needed
renderBinary(Play.getFile("yourfile!"));
}
public static void isDownloadFinished(){
Stream<String> userStream = Cache.get(session.getId(),Stream.class);
List<IndexedEvent<String>> list = await(userStream.nextEvents(0));
renderJSON(list.get(0).data);
}
#After(only="download")
static void after(){
Stream<String> userStream = Cache.get(session.getId(),Stream.class);
userStream.publish("ok");
}
on your html...
#{extends 'main.html' /}
#{set title:'downloadPage' /}
download
<script>
$(document).ready(function(){
$.ajax('/application/isDownloadFinished',{success:function(data){
if(data){
console.log("downloadFinished");
}
}});
});
</script>
when your download finished, the original page will retrieve the notification.
This code is just a sample. You could read the api of ArchivedEventStream and make your own implementation..

Java File Transfer API

I need to transfer files to my web server for processing and I'd like to do it in a generic way if possible.
I need to be able to transfer files from the following protocols at a minimum (with more to follow eventually):
HTTP
FTP
SCP
I'd really like to be able to send files to SMTP also
So my question, is there a toolkit available that does this already? If so, it must be open source as this is part of an open source project.
If there isn't a toolkit that already does this, what is the best way to structure an interface that will handle most file transfers?
I've thought about something like this:
public interface FileTransfer {
public void connect(URL url, String userid, String password);
public void disconnect();
public void getFile(String sourceFile, File destFile);
public void putFile(File sourceFile, File destFile);
}
And then a Factory that takes the source URL or protocol and instantiates the correct file handler.

Apache commons VFS speaks to this problem, although a quick check didn't show that it will do SCP or SMTP. Commons NET does SMTP, but I don't know that you could get the common interface out of the box. For SCP, here are some possibilities.
The bottom line seems to be to check out the VFS implementation and see if it does something for you, perhaps you can extend it for different protocols. If it isn't appropriate, regarding your interface, you are probably going to want all remote file references to be Strings rather than File objects, and specifically a string representing a URI pointing to the remote location and telling you what protocol to use.

I'm working at a problem very similar to yours, I couldn't find any open source solution so I'm trying to sketch a solution myself. This is what I've come up with.
I think you should represent inputSources and outputSources as different things, like
public interface Input{
abstract InputStream getFileInputStream();
abstract String getStreamId();
}
//You can have differen implementation of this interface (1 for ftp, 1 for local files, 1 for Blob on db etc)
public interface Output{
abstract OutputStream getOutputStream();
abstract String getStreamId();
}
//You can have differen implementation of this interface (1 for ftp, 1 for local files, 1 for mailing the file etc)
Then you should have a Movement to describe which input should go to which output.
class Movement{
String inputId;
String outputId;
}
A class to describe the list of Movement to make.
class MovementDescriptor{
public addMovement(Movement a);
public Movement[] getAllMovements();
}
And then a class to perform the work itself.
class FileMover{
HashMap<String,Input> inputRegistry;
HashMap<String,Output> outputRegistry;
addInputToRegistry(Input a ){
inputRegistry.put(a.getId(),a);
}
addOutputToRegistry(Output a){
outputRegistry.put(a.getId(),a);
}
transferFiles(MovementDescriptor movementDescriptor){
Movement[] movements =movementDescriptor.getAllMovements();
foreach (Movement movement: movements){
//get the input Id
//find it in the registry and retrieve the associated InputStream
//get the output Id
//find it in the registry and retrieve the associated OutputStream
//copy the stream from the input to the output (you may want to use a temporary file in between)
}
}
}
The code that would use this would operate like this:
FileMover fm=new FileMover();
//Register your sources and your destinations
fm.addInputToRegistry(input);
fm.addOutputToRegistry(output)
// each time you have to make a movement create a MovementDescriptor and call
fm.transferFiles(movementDescriptor)
If you would like to exchange by mail our views on the subject, just send me an e mail at (my nickname)#gmail dot com.
NOTE: The code is just a sketch :-)

I think JSch implements SCP, so that covers that one.

please make use of JCraft . Open "sftp" channel and try that.