Please find me a reason why I have done this? \u2014 No, no… I don’t need any excuse, Windows is a great operating system and the PowerShell is an overdue extention to it *cough, cough, the hurts, ahh I’m dying!*<\/i> \u2014 But seriously, due to the system environment at my workplace, I am mainly working with Microsoft Windows and affiliated programs, such as Microsoft Office (Outlook) and Lync. This does not reflect my personal preference, but adaption is key sometimes.<\/p>\n
In fact the Windows PowerShell<\/a> is really not as bad, as the name might suggest it to be (plus, the name<\/a> is not<\/a> claimed<\/a>, yet). The Power<\/i>Shell is a quite power<\/i>full framework when it comes to task automation and configuration management in an Windows environment. Due to its scripting capabilities and its full access to COM<\/a> and WMI<\/a> it is a major leap compared to its "predecessor", the Windows Command Prompt. The concept of cmdlets<\/a> and especially the object-oriented pipes are a somewhat modern approach of the "old school" executables and text-based pipes. But<\/b> \u2014 and this is a bold-but<\/b> \u2014 is probably a blessing and a curse at once.<\/p>\n <\/p>\n As always if you follow a new approach in programming, interoperability and commutability are two major challenges to face in development. Unsuprisingly as I tried to take advantage of the PowerShells capabilities, I painfully realized: Microsoft hasn’t tackled any of those, or did they? Let the devil take the hindmost! Now you could argue, why should you combine a platform-independent programming language such as Java, with a heavily platform dependent framework as the PowerShell? Simple answer, Java is a very sophisticated programming language, the PowerShell offers a very elegant way of accessing the programs I have to work with. Fusion<\/strong><\/a>.<\/p>\n Java is capable of communicating using text- and\/or binary pipes, such as they are used in the old Windows Command Line or any Unix shell. A few lines of code are enough to easily utilize those:<\/p>\n So what’s it with the Windows PowerShell? Simply using the above code? Well, not in the first place at least.<\/p>\n The default in- and output pipes of the Windows PowerShell do not talk text (…or do they?)! In my thoughts there was no way of pushing Java Objects to the PowerShell’s object-pipes (cause obviously Java Objects ≠ PowerShell Objects). So I got my hands on the Invoke-Expression cmdlet<\/a> and the mission was set:<\/p>\n This does definitely not sound like a way to go, but what should I say? I’m The man who made a monster<\/a>… which is threadsafe, does garbage collection and utilizes shutdown hooks. Please take a quick peak at the monster<\/a> … and delete it right afterwards cause:<\/p>\n After hours of programming and to make a long story short, I found out that simply invoking the above script using the following exec-command:<\/p>\n\r\nimport java.io.IOException;\r\nimport java.io.InputStream;\r\nimport java.io.OutputStream;\r\nimport java.io.PrintWriter;\r\n\r\npublic class ShellExample {\r\n\tpublic static void main(String[] args) throws IOException, InterruptedException {\r\n\t\t\/\/start a cmd \/ shell-instance (also works with \/bin\/sh)\r\n\t\tfinal Process process = Runtime.getRuntime().exec("cmd");\r\n\t\t\/\/handle the data of the input stream (non-blocking)\r\n\t\tpipe(process.getInputStream(),System.out);\r\n\t\t\/\/handle the data of the error stream (non-blocking)\r\n\t\tpipe(process.getErrorStream(),System.err);\r\n\t\t\r\n\t\t\/\/pass the commands to the output stream\r\n\t\tPrintWriter commands = new PrintWriter(process.getOutputStream(),true);\r\n\t\tcommands.println("cd");\r\n\t\tcommands.println("dir");\r\n\t\tcommands.close();\r\n\t\t\r\n\t\t\/\/wait for the process to close\r\n\t\tprocess.waitFor();\r\n\t}\r\n\t\r\n\tprivate static void pipe(final InputStream from,final OutputStream to) {\r\n\t\tnew Thread(new Runnable() {\r\n\t\t\t@Override public void run() {\r\n\t\t\t\tint length; byte[] buffer = new byte[128];\r\n\t\t\t\ttry {\r\n\t\t\t\t\twhile((length=from.read(buffer))!=-1)\r\n\t\t\t\t\t\tto.write(buffer,0,length);\r\n\t\t\t\t} catch(IOException e) { e.printStackTrace(); }\r\n\t\t\t\tfinally {\r\n\t\t\t\t try { from.close(); }\r\n\t\t\t\t\tcatch(IOException e) { \/* ... *\/ }\r\n\t\t\t\t}\r\n\t\t\t}\r\n\t\t}).start();\r\n\t}\r\n}\r\n<\/pre>\n\n