I need to write a code for competition using STDIN and STDOUT, how can I set up eclipse to take input from STDIN??
When I was just using editor and command line I was running:
java Hatch < hatch_input
Now I need the equivalent to work directly from eclipse. It would be perfect if I could use it directly from file, but it would to suffice to just be able to paste the actual input somewhere, as long as I can write code that takes STDIN directly in eclipse by clicking RUN.
class Main{
public static void main (String[] args) throws java.lang.Exception{
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
}
}
Above code is what I am trying to achieve.
When you run your program you can setup a run configuration. Just click on on the arrow next to the play button and choose "Run configurations..."
In the new run configuration dialog you create a new Java application run configuration. In the tab "Arguments" you can enter the arguments you want the program to receive.
Suggestion: In the last tab, "common", choose to save it as a shared file, this will create a *.launch file that you can use to quickly run the program. You can also create different launch files for different inputs.
You can also just type in the input data or copy paste in the console window of the eclipse. for Sdtin when the program hits that point focus shifts to console and waits for the response.
There is following code,which i tried. this code is working fine if you run program in command prompt, but in eclipse not working because there console are no longer waiting for user input and give the java.lang.NullPointerException.
if you are read data by user input you can use System.in.read(). and this is also working in eclipse console.
In this code you can get Data from user but this data is not args which we throw at run time...
public class CONSOLE
{
public static void main(String[] args)
{
// TODO Auto-generated method stub
Console c = System.console();
System.out.println("Enter Username : \t");
String u = c.readLine();
System.out.println("Enter Password : \t");
char[] p = c.readPassword();
System.out.println("USERNAME : "+u);
System.out.println("PASSWORD : "+String.valueOf(p));
}
}
Scanner sc=new Scanner(System.in);
String s=sc.nextLine();
Related
While developing an Eclipse plug-in, I want to output some paths in the console and then add some hyperlinks to those paths.
Instead of parsing the console, I thought about calculating the hyperlinks locations by the string which holds the path length which I print in console.
The problem which I have is that I try to create the hyperlink, but the information isn't printed yet in the console, therefore I get random bad location exceptions. It works if I run it in debug mode and I have a breakpoint on the hyperlink creation loop.
I tried to separate the creation of hyperlinks and wait until the messageQueue is empty, but that didn't work out.
private BlockingQueue<String> messageQueue = Queues.newLinkedBlockingQueue()
for ( String message : messages) {
messageQueue.offer(message);
// here I create a new HyperLinkInformation object and put it in a list
}
// wait until the queue is empty
while(!messageQueue.isEmpty()) {}
for (HyperLink hyperLinkObj : hyperlinkInformations) {
// try to create the hyperlink
}
Any ideas on how I could check if the console still has something to print?
I have a Visual Studio extension package where I am applying C++ syntax settings to custom file extensions. This is done in the Visual Studio's Text Editor options. Those files are plain text and I mean to have them behave as code files in the IDE (IntelliSense, find matching braces, etc...)
It's mostly working fine, but there is one problem. The C++ syntax context is not applied to whichever is the first file I open in a given Visual Studio session. I will launch Visual Studio, open one of our custom projects, and open one file. The IDE opens a document window and the file is opened, can be edited and saved, no problem in appearance. But the file behaves as a plain text and not a C++ source. Now, whenever I open a second file in the IDE, or any further file, the C++ settings do get applied successfully. I can close all document tabs, and open new ones, and all those tabs are fine. Even re-opening the first file in a new tab, or after re-loading the project or the solution, is fine. Only the first document opened in a Visual Studio session has the issue.
For the following segment, I will refer to the Microsoft documentation on using their standard editor: https ://msdn.microsoft.com/en-us/library/bb166504.aspx
To implement the OpenItem method with a standard editor
1.Call IVsRunningDocumentTable (RDT_EditLock) to determine whether the document data object file is already open.
2.If the file is already open, resurface the file by calling the IsDocumentOpen method, specifying a value of IDO_ActivateIfOpen for the grfIDO parameter.
If the file is open and the document is owned by a different project than the calling project, your project receives a warning that the editor being opened is from another project. The file window is then surfaced.
3.If the document is not open or not in the running document table, call the OpenStandardEditor method (OSE_ChooseBestStdEditor) to open a standard editor for the file.
When you call the method, the IDE performs the following tasks:
a.The IDE scans the Editors/{guidEditorType}/Extensions subkey in the registry to determine which editor can open the file and has the highest priority for doing this.
b.After the IDE has determined which editor can open the file, the IDE calls CreateEditorInstance. The editor's implementation of this method returns information that is required for the IDE to call CreateDocumentWindow and site the newly opened document.
c.Finally, the IDE loads the document by using the usual persistence interface, such as IVsPersistDocData2.
d.If the IDE has previously determined that the hierarchy or hierarchy item is available, the IDE calls GetItemContext method on the project to get a project-level context IServiceProvider pointer to pass back in with the CreateDocumentWindow method call.
4.Return an IServiceProvider pointer to the IDE when the IDE calls GetItemContext on your project if you want to let the editor get context from your project.
Performing this step lets the project offer additional services to the editor.
If the document view or document view object was successfully sited in a window frame, the object is initialized with its data by calling LoadDocData.
It definitely seems to me that I need to hit element (D) from the above instructions. I have debuged through my extension code, and I do see where my implementation of GetItemContext() comes into play. When I open most files, the code path does effectively go through this method, however it does not when I open the first file of a Visual Studio session.
Call stack from OpenStandardEditor
GetItemContext is invoked by the Microsoft assemblies and I do not know what is the condition that triggers whether it is called or not. I can only trace up to my call to the method OpenStandardEditor(), in FileDocumentManager.cs, then I don't know what happens beyond that. The above screenshot is the call stack when GetItemContext is successfully invoked, but when I'm opening the first file I'm totally in the dark as to what OpenStandardEditor is doing. I do know that in both cases, when the context is loaded and when it is not, the exact same parameter values are passed to OpenStandardEditor. So here's my code where this method is invoked, if that can be of some help:
My override of class DocumentManager:
private int Open(bool newFile, bool openWith, uint editorFlags, ref Guid editorType, string physicalView, ref Guid logicalView, IntPtr docDataExisting, out IVsWindowFrame windowFrame, WindowFrameShowAction windowFrameAction)
{
windowFrame = null;
if (this.Node == null || this.Node.ProjectMgr == null || this.Node.ProjectMgr.IsClosed)
{
return VSConstants.E_FAIL;
}
int returnValue = VSConstants.S_OK;
string caption = this.GetOwnerCaption();
string fullPath = this.GetFullPathForDocument();
// Make sure that the file is on disk before we open the editor and display message if not found
if (!((FileNode)this.Node).IsFileOnDisk(true))
{
// Inform clients that we have an invalid item (wrong icon)
this.Node.OnInvalidateItems(this.Node.Parent);
// Bail since we are not able to open the item
return VSConstants.E_FAIL;
}
IVsUIShellOpenDocument uiShellOpenDocument = this.Node.ProjectMgr.Site.GetService(typeof(SVsUIShellOpenDocument)) as IVsUIShellOpenDocument;
IOleServiceProvider serviceProvider = this.Node.ProjectMgr.Site.GetService(typeof(IOleServiceProvider)) as IOleServiceProvider;
try
{
int result = VSConstants.E_FAIL;
if (openWith)
{
result = uiShellOpenDocument.OpenStandardEditor((uint)__VSOSEFLAGS.OSE_UseOpenWithDialog, fullPath, ref logicalView, caption, this.Node.ProjectMgr, this.Node.ID, docDataExisting, serviceProvider, out windowFrame);
}
else
{
__VSOSEFLAGS openFlags = 0;
if (newFile)
{
openFlags |= __VSOSEFLAGS.OSE_OpenAsNewFile;
}
//NOTE: we MUST pass the IVsProject in pVsUIHierarchy and the itemid
// of the node being opened, otherwise the debugger doesn't work.
if (editorType != Guid.Empty)
{
result = uiShellOpenDocument.OpenSpecificEditor(editorFlags, fullPath, ref editorType, physicalView, ref logicalView, caption, this.Node.ProjectMgr, this.Node.ID, docDataExisting, serviceProvider, out windowFrame);
}
else
{
openFlags |= __VSOSEFLAGS.OSE_ChooseBestStdEditor;
// THIS IS THE CALL THAT I'M ALWAYS INVOKING. PARAMS ARE ALWAYS THE SAME, BUT ITEM CONTEXT IS NOT ACTIVATED FOR FIRST FILE OF A SESSION.
result = uiShellOpenDocument.OpenStandardEditor((uint)openFlags, fullPath, ref logicalView, caption, this.Node.ProjectMgr, this.Node.ID, docDataExisting, serviceProvider, out windowFrame);
}
}
if (result != VSConstants.S_OK && result != VSConstants.S_FALSE && result != VSConstants.OLE_E_PROMPTSAVECANCELLED)
{
ErrorHandler.ThrowOnFailure(result);
}
if (windowFrame != null)
{
object var;
if (newFile)
{
ErrorHandler.ThrowOnFailure(windowFrame.GetProperty((int)__VSFPROPID.VSFPROPID_DocData, out var));
IVsPersistDocData persistDocData = (IVsPersistDocData)var;
ErrorHandler.ThrowOnFailure(persistDocData.SetUntitledDocPath(fullPath));
}
var = null;
ErrorHandler.ThrowOnFailure(windowFrame.GetProperty((int)__VSFPROPID.VSFPROPID_DocCookie, out var));
this.Node.DocCookie = (uint)(int)var;
if (windowFrameAction == WindowFrameShowAction.Show)
{
ErrorHandler.ThrowOnFailure(windowFrame.Show());
}
else if (windowFrameAction == WindowFrameShowAction.ShowNoActivate)
{
ErrorHandler.ThrowOnFailure(windowFrame.ShowNoActivate());
}
else if (windowFrameAction == WindowFrameShowAction.Hide)
{
ErrorHandler.ThrowOnFailure(windowFrame.Hide());
}
}
}
catch (COMException e)
{
Trace.WriteLine("Exception e:" + e.Message);
returnValue = e.ErrorCode;
this.CloseWindowFrame(ref windowFrame);
}
return returnValue;
}
I have also tried an alternative. In the call stack where I perform DoDefaultAction on my FileNode (extends HierarchyNode), I normally call an instance of my DocumentManager.Open() directly. I have changed that to try OpenDocumentViaProject() instead. Now, the MSENV assembly turns out to call my GetItemContext, then goes out to my implementation of DocumentManager.Open I quoted above.
Call stack from OpenDocumentViaProject
Sounds promising... but no. Beyond the screenshot above, once I call OpenStandardEditor the exact same behavior happens. No project context is applied to the first document opened in a session, and the context is applied to every further file. The call to GetItemContext() that is done by OpenDocumentViaProject() does not seem to matter in the slightest. Only when OpenStandardEditor() also ends up calling GetItemContext() somewhere downstream does the project settings I want get applied.
I don't see where I would be doing something fundamentally wrong. It seems to me that I am following the Mimcrosoft instructions on opening standard editors. Would you have a clue as to how my GetItemContext implementation is not invoked when I'm opening the first file of a VS session? Thanks
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);
This may not be possible but I'm looking for a way to add a button (or option in right click menu of project) that allows me to perform what would normally be multiple separate actions , specifically I would like an option that would:
perform a Maven clean on the current project
clean the project in eclipse
clean the server and rebuild (normally or Debug)
I have tried to Google this but I couldn't find anything that might help (I may not of phrased it correctly though as I am not sure what to search for)
All of the actions you listed can be done by separate builders. So you can create a launch config to run the Maven clean action, another launch config to run the Eclipse clean command and so on.
When you have all of those launch configs available, install the CDT launch group feature to run them together with one click: https://stackoverflow.com/a/11905444/44089
There have been a number of scripting attempts with eclipse, but not many of them are successful. You can always write your own command and handler, and from there you can execute any number of commands that you can specify:
public Object execute(ExecutionEvent event) throws ExecutionException {
IWorkbenchWindow window = HandlerUtil
.getActiveWorkbenchWindowChecked(event);
IHandlerService handlerService = (IHandlerService) window
.getService(IHandlerService.class);
try {
handlerService.executeCommand(
IWorkbenchCommandConstants.HELP_ABOUT, null);
handlerService.executeCommand(
IWorkbenchCommandConstants.FILE_REFRESH, null);
} catch (NotDefinedException | NotEnabledException
| NotHandledException e) {
throw new ExecutionException("Failed", e);
}
return null;
}
Then you just need to track down command IDs that correspond to what you want to do. ALT+SHIFT+F2 and then selecting a menu item can provide the command ID (or action definition ID, which is the same thing).
I have a Groovy script which is run like this:
File scriptFile = ...;
ScriptEngine engine = ...;
String script = FileUtils.readFileToString(scriptFile);
Object evalResult = engine.eval(script, bindings);
Unsurprisingly, breakpoint set in the script file doesn't trigger. What can I change to make it work? The script needs to be run in the context of the larger program (no separate launch configuration), and through a ScriptEngine, and the file is only known at runtime.
I'm using this hack: I've defined a Java class Debugger which looks like this:
public class Debugger {
private static final Logger log = LoggerFactory.getLogger( Debugger.class );
/**
* Invoke this method anywhere to end up in the Java debugger.
*
* <p>Sometimes, you have code that might eventually be executed or you have a place
* where you want to stop but no code line.
*
* <p>In these case, use this method.
*
* <p>Don't forget to set a breakpoint, first :-)
* */
public static void stopInDebugger() {
log.error( "Please set a breakpoint in Debugger.stopInDebugger() and try again whatever you just did!" );
}
}
I have a breakpoint in the log.error line in Ecipse.
Now, I can put this line into the script where I want a breakpoint:
Debugger.stopInDebugger();
Granted, it doesn't allow me to easily step through the script but it's better than nothing.
Is your script file in a source folder on the classpath (sounds like it's not)? If not, make it so. You can also change your preferences to ensure that the script file is never compiled by the compiler (and optionally not even copied to the output folder). Go to Preferences -> Groovy -> Compiler and look at script folders to make this happen.