I have a perl program that dynamically generate images based on given width. I need to create web service that takes image dimensions from client, and pass it to the perl program to create the image then send it back to the client.
Now on Jelastic cloud, I created 3 nodes:
Node 1: for tomcat (contains the java code).
Node 2: for MySql (contains the database).
Node 3: for Centos VPS (contains the perl code).
My questions:
I'm I doing the right thing?? if not what is the best way to do my program?
How can I call the perl code (in node 3) from the java service (in node 1), and return the generated image back to client.
It sounds a reasonable design. You would write something like this.
import java.lang.Runtime;
int width = 99;
try {
Runtime runt = Runtime.getRuntime()
Process proc = runt.exec('/usr/bin/perl', '/path/to/myperl.pl', Integer.toString(width));
proc.waitFor();
}
catch (Exception ioe) {
ioe.printStackTrace();
}
Of course you'll have to adjust /usr/bin/perl to where your own perl exeutable really is, or you could invoke the shell to get it to search the path by using
runt.exec( '/bin/bash', '-c', 'perl', '/path/to/myperl.pl', Integer.toString(width) );
As for how to get the image back to the client, you don't say much about how your Perl program works, but either you tell it where to write the file or it decides for itself and tells you where it's put it afterwards
If it's the former, then you presumably pass the path on the command line, so you just have to extend the call to runt.exec above to pass another parameter
If it's the latter, then presumably the program prints to STDOUT where it has put the new file, and you need to read that stream from your Java code to collect the information. That would look like this in place of the proc.waitFor() call
import java.io.*;
BufferedReader inp = new BufferedReader(
new InputStreamReader(proc.getInputStream())
);
while ( ( line = inp.readLine() ) != null ) {
// Process output of Perl code to get file location
}
How can I change the current working directory from within a Java program? Everything I've been able to find about the issue claims that you simply can't do it, but I can't believe that that's really the case.
I have a piece of code that opens a file using a hard-coded relative file path from the directory it's normally started in, and I just want to be able to use that code from within a different Java program without having to start it from within a particular directory. It seems like you should just be able to call System.setProperty( "user.dir", "/path/to/dir" ), but as far as I can figure out, calling that line just silently fails and does nothing.
I would understand if Java didn't allow you to do this, if it weren't for the fact that it allows you to get the current working directory, and even allows you to open files using relative file paths....
There is no reliable way to do this in pure Java. Setting the user.dir property via System.setProperty() or java -Duser.dir=... does seem to affect subsequent creations of Files, but not e.g. FileOutputStreams.
The File(String parent, String child) constructor can help if you build up your directory path separately from your file path, allowing easier swapping.
An alternative is to set up a script to run Java from a different directory, or use JNI native code as suggested below.
The relevant OpenJDK bug was closed in 2008 as "will not fix".
If you run your legacy program with ProcessBuilder, you will be able to specify its working directory.
There is a way to do this using the system property "user.dir". The key part to understand is that getAbsoluteFile() must be called (as shown below) or else relative paths will be resolved against the default "user.dir" value.
import java.io.*;
public class FileUtils
{
public static boolean setCurrentDirectory(String directory_name)
{
boolean result = false; // Boolean indicating whether directory was set
File directory; // Desired current working directory
directory = new File(directory_name).getAbsoluteFile();
if (directory.exists() || directory.mkdirs())
{
result = (System.setProperty("user.dir", directory.getAbsolutePath()) != null);
}
return result;
}
public static PrintWriter openOutputFile(String file_name)
{
PrintWriter output = null; // File to open for writing
try
{
output = new PrintWriter(new File(file_name).getAbsoluteFile());
}
catch (Exception exception) {}
return output;
}
public static void main(String[] args) throws Exception
{
FileUtils.openOutputFile("DefaultDirectoryFile.txt");
FileUtils.setCurrentDirectory("NewCurrentDirectory");
FileUtils.openOutputFile("CurrentDirectoryFile.txt");
}
}
It is possible to change the PWD, using JNA/JNI to make calls to libc. The JRuby guys have a handy java library for making POSIX calls called jnr-posix. Here's the maven info
As mentioned you can't change the CWD of the JVM but if you were to launch another process using Runtime.exec() you can use the overloaded method that lets you specify the working directory. This is not really for running your Java program in another directory but for many cases when one needs to launch another program like a Perl script for example, you can specify the working directory of that script while leaving the working dir of the JVM unchanged.
See Runtime.exec javadocs
Specifically,
public Process exec(String[] cmdarray,String[] envp, File dir) throws IOException
where dir is the working directory to run the subprocess in
If I understand correctly, a Java program starts with a copy of the current environment variables. Any changes via System.setProperty(String, String) are modifying the copy, not the original environment variables. Not that this provides a thorough reason as to why Sun chose this behavior, but perhaps it sheds a little light...
The working directory is a operating system feature (set when the process starts).
Why don't you just pass your own System property (-Dsomeprop=/my/path) and use that in your code as the parent of your File:
File f = new File ( System.getProperty("someprop"), myFilename)
The smarter/easier thing to do here is to just change your code so that instead of opening the file assuming that it exists in the current working directory (I assume you are doing something like new File("blah.txt"), just build the path to the file yourself.
Let the user pass in the base directory, read it from a config file, fall back to user.dir if the other properties can't be found, etc. But it's a whole lot easier to improve the logic in your program than it is to change how environment variables work.
I have tried to invoke
String oldDir = System.setProperty("user.dir", currdir.getAbsolutePath());
It seems to work. But
File myFile = new File("localpath.ext");
InputStream openit = new FileInputStream(myFile);
throws a FileNotFoundException though
myFile.getAbsolutePath()
shows the correct path.
I have read this. I think the problem is:
Java knows the current directory with the new setting.
But the file handling is done by the operation system. It does not know the new set current directory, unfortunately.
The solution may be:
File myFile = new File(System.getPropety("user.dir"), "localpath.ext");
It creates a file Object as absolute one with the current directory which is known by the JVM. But that code should be existing in a used class, it needs changing of reused codes.
~~~~JcHartmut
You can use
new File("relative/path").getAbsoluteFile()
after
System.setProperty("user.dir", "/some/directory")
System.setProperty("user.dir", "C:/OtherProject");
File file = new File("data/data.csv").getAbsoluteFile();
System.out.println(file.getPath());
Will print
C:\OtherProject\data\data.csv
You can change the process's actual working directory using JNI or JNA.
With JNI, you can use native functions to set the directory. The POSIX method is chdir(). On Windows, you can use SetCurrentDirectory().
With JNA, you can wrap the native functions in Java binders.
For Windows:
private static interface MyKernel32 extends Library {
public MyKernel32 INSTANCE = (MyKernel32) Native.loadLibrary("Kernel32", MyKernel32.class);
/** BOOL SetCurrentDirectory( LPCTSTR lpPathName ); */
int SetCurrentDirectoryW(char[] pathName);
}
For POSIX systems:
private interface MyCLibrary extends Library {
MyCLibrary INSTANCE = (MyCLibrary) Native.loadLibrary("c", MyCLibrary.class);
/** int chdir(const char *path); */
int chdir( String path );
}
The other possible answer to this question may depend on the reason you are opening the file. Is this a property file or a file that has some configuration related to your application?
If this is the case you may consider trying to load the file through the classpath loader, this way you can load any file Java has access to.
If you run your commands in a shell you can write something like "java -cp" and add any directories you want separated by ":" if java doesnt find something in one directory it will go try and find them in the other directories, that is what I do.
Use FileSystemView
private FileSystemView fileSystemView;
fileSystemView = FileSystemView.getFileSystemView();
currentDirectory = new File(".");
//listing currentDirectory
File[] filesAndDirs = fileSystemView.getFiles(currentDirectory, false);
fileList = new ArrayList<File>();
dirList = new ArrayList<File>();
for (File file : filesAndDirs) {
if (file.isDirectory())
dirList.add(file);
else
fileList.add(file);
}
Collections.sort(dirList);
if (!fileSystemView.isFileSystemRoot(currentDirectory))
dirList.add(0, new File(".."));
Collections.sort(fileList);
//change
currentDirectory = fileSystemView.getParentDirectory(currentDirectory);
I need to customize other's code,
so I found they used
Mage::getSingleton('core/session')->getMyCustomBlockInfo();
in Order.php file for custom order email
so I can't find this function getMyCustomBlockInfo();
Can anyone tell me where this function reside?
Thanks
those are magic functions get() and set() and you are asking a session variable there that is set as
Mage::getSingleton('core/session')->setMyCustomBlockInfo();
somewhere in your code. If you use terminal you can easily find by making a following grep:
grep '>setMyCustomBlockInfo(' . -rsni
and it will list the files where your variable is set to session.
example :
Mage::getModel('catalog/product'); //or
Mage::getSingleton('catalog/product');
the code must be in '../app/core/Mage/Catalog/Model/Product.php' file
then
Mage::getSingleton('core/session');
the code must be in '../app/core/Mage/Core/Model/Session.php' file
because the class Mage_Core_Model_Session's parent::parent is Varien_Object, then you can do all magic functions and you can ->getData() to see the Data inside.
Mage::getSingleton('core/session')->getData();
on your problem when go call ->getData() you can see data : [my_custom_block_info]
you can set it with call
Mage::getSingleton('core/session')->setMyCustomBlockInfo('what');
Mage::getSingleton('core/session')->getMyCustomBlockInfo();
// will return 'what'
I would like to know if its possible to access the SSRS SOAP API from Perl. I have written some C# applications that use SSRS, but most of my code base is in Perl running on Unix. I am not really familiar with SOAP at all.
I would like to know if its even possible, and if it is, I would like to know how to code up the following example int perl:
http://msdn.microsoft.com/en-us/library/reportservice2010.reportingservice2010.listchildren.aspx
Thanks
EDIT:
I am only looking for an example of how to connect and execute a function.
In essence, I am looking on how to write the following(simplified) C# code in Perl?
ReportingService2010 rs = new ReportingService2010();
rs.Url = "<server adress here>";
rs.Credentials = System.Net.CredentialCache.DefaultCredentials;
CatalogItem[] items = rs.ListChildren("/", true);
foreach (CatalogItem i in items){
Console.WriteLine(i.Name);
}
I know 2 way for it
SOAP::Lite https://github.com/mishin/presentation/blob/master/4_trans/02_SOAP_Lite.pl
XMLRPC::Lite https://github.com/mishin/presentation/blob/master/4_trans/03_2_XMLRPC_Lite.pl
Hello I'm trying to control FastHenry2 via Windows automation with Matlab.
I'm new to that topic. If I understood everything right I have to open it:
ax=actxserver('FastHenry2.Document');
and than run the function I want with the handle?
ax.Run('coils1.inp')
but that doesn't work. Matlab can't find Run and uses run instead, which is some build in Function not related at all with the problem. Also all other Function this UI should support don't work either. For Example FastHenry2.IsRunning or FastHenry2.GetInductance. So I guess I do something wrong with the whole UI handling. FastHenry provides an example script using VBS which I attached bellow and since it works fine FastHenry should be installed right on computer. I'm thankful for every hint I can get.
so long
eactor
The following VBS example works fine
Dim FastHenry2
pathPos = InstrRev(Wscript.ScriptFullName, Wscript.ScriptName)
path = left(Wscript.ScriptFullName, pathPos-1)
Set FastHenry2 = CreateObject("FastHenry2.Document")
couldRun = FastHenry2.Run("""" + path + "coils1.inp""")
Do While FastHenry2.IsRunning = True
Wscript.Sleep 500
Loop
inductance = FastHenry2.GetInductance()
WScript.Echo "Coils1 mutual inductance is " + CStr(inductance(0, 0, 1))
FastHenry2.Quit
Set FastHenry2 = Nothing
You might need to use an alternate syntax. Instead of
FastHenry2.Run('coils1.inp')
try this.
invoke(FastHenry2, 'Run', 'coils2.inp')
I've had to do this for some methods on the Excel.Application ActiveX control. I'm not clear why the first syntax doesn't work in some cases.