"Denz" <RU*****@RUBBISHhotmail.com> wrote in message
news:Hz****************@news-server.bigpond.net.au...
Something like this Console class would be
great. Ive just downloaded JCurses but so far looks
like overkill- when just a few methods like clear screen
and cursor position would go such a long way...
I quite like JCurses, *but* I fully agree with you - too much functionality.
Having thought about it a little more, all that is minimally required:
* Console information accessor [e.g. get max lines, columns, etc]
* A clear screen method
* Cursor position set / get methods
* A character read method i.e. accept a sing;le character
without needing to press ENTER [could be designed to
also accept 'special' keys like F1, though best, I think, to
keep it simple and ignore non-standard keys]
with other functionality such as:
* A string read method [e.g. up to X characters in
length without pressing ENTER; ESC could abort
input process; extend to not echo typed keys so
as to allow password-type input]
* Support character atributes like colour etc
* Cursor hide / unhide
would be purely optional.
It is easy enough to make a start with this by creating a Console class:
public class Console
{
public static native int getMaxRows();
public static native int getMaxCols();
public static native void cls();
public static native int getCurRow();
public static native int getCurCol();
public static native void setCurPos(int row, int col);
public static native char inputKey(int[] keyData);
}
Below you will find a JNI implementation for such a class. Since we're
dealing with JNI such code is strictly system-specific, so will work only on
the targeted platform, in this case, Win32 i.e. it should run ok on all
Win9x and up platforms.
The included files:
* A batch file called 'mkConsole.bat' used to document / generate
the steps in creating the native code
* The Java source files:
- Console.java, the Java interface to the JNI routines
- TestConsole.java, a minimal test harness for these routines
* C++ source files:
- Console.h
- ConsoleImp.cpp
Assuming you use a Win32 system [I hope so :)] you will need to provide:
* C++ Compiler capable of generating Win32 DLL's
* Suitable 'make' file for this compiler
The code was tested with Borland 5.5.1 and J2SDK 1.4.1, and appears to work
ok. The code is provided 'as is' for educational purposes. It goes without
saying that I accept no reponsibility for this code's use by others.
It may be worthwhile for anyone contemplating the use of this code to first:
* Read the JNI tutorial on the Sun site
* Consult Win32 documentation regarding 'console applications'
for some insight into the code
Sadly, the codes its provision alienates a substantial segment of the Java
community. It is hoped, though, that other may be motivated to implement
this, or similar functionality, for their own platform, and - hopefully -
post it. It would be interesting to see how these simple tasks are performed
on other platforms.
I hope this helps.
Anthony Borla
// FILE: mkConsole.bat ========================
@echo off
:: Compile JAVA Source containing Native Method calls
javac -deprecation TestConsole.java
:: Create .h header from Java Source
javah -jni TestConsole
:: Implement Native Method (C++) and create a .DLL
:: 1) Compile ConsoleImp.cpp
:: 2) Create ConsoleImp.dll
:: *** You need to implement this for your compiler ***
make -fConsoleImp.mak
:: Execute Java Program which calls Native Method
:: 1) Loads ConsoleImp.dll
:: 2) Calls 'Console' native method
java TestConsole
// FILE: Console.java ========================
public class Console
{
// Load DLL
static
{
try
{
System.loadLibrary("ConsoleImp");
}
catch (UnsatisfiedLinkError e)
{
System.out.println("Could not locate DLL");
System.exit(1);
}
}
public static native int getMaxRows();
public static native int getMaxCols();
public static native void cls();
public static native int getCurRow();
public static native int getCurCol();
public static native void setCurPos(int row, int col);
public static native char inputKey(int[] keyData);
}
// FILE: TestConsole.java =====================
public class TestConsole
{
public static void main(String[] args)
{
System.out.println("Start...");
Console.cls();
System.out.println(Console.getMaxRows());
System.out.println(Console.getMaxCols());
Console.setCurPos(10, 5);
System.out.println(Console.getCurRow());
System.out.println(Console.getCurCol());
char key;
int[] keyData = new int[]{0, 0};
System.out.print("Press a key: ");
key = Console.inputKey(keyData);
System.out.print(key + ", " + (int)key);
if (key == 0)
System.out.println("A special key was pressed");
System.out.println("Key Code: " + keyData[0]);
System.out.println("Key Scan: " + keyData[1]);
System.out.println("End...");
}
}
// FILE: Console.h ========================
/* DO NOT EDIT THIS FILE - it is machine generated */
#include <jni.h>
/* Header for class Console */
#ifndef _Included_Console
#define _Included_Console
#ifdef __cplusplus
extern "C" {
#endif
/*
* Class: Console
* Method: getMaxRows
* Signature: ()I
*/
JNIEXPORT jint JNICALL Java_Console_getMaxRows
(JNIEnv *, jclass);
/*
* Class: Console
* Method: getMaxCols
* Signature: ()I
*/
JNIEXPORT jint JNICALL Java_Console_getMaxCols
(JNIEnv *, jclass);
/*
* Class: Console
* Method: cls
* Signature: ()V
*/
JNIEXPORT void JNICALL Java_Console_cls
(JNIEnv *, jclass);
/*
* Class: Console
* Method: getCurRow
* Signature: ()I
*/
JNIEXPORT jint JNICALL Java_Console_getCurRow
(JNIEnv *, jclass);
/*
* Class: Console
* Method: getCurCol
* Signature: ()I
*/
JNIEXPORT jint JNICALL Java_Console_getCurCol
(JNIEnv *, jclass);
/*
* Class: Console
* Method: setCurPos
* Signature: (II)V
*/
JNIEXPORT void JNICALL Java_Console_setCurPos
(JNIEnv *, jclass, jint, jint);
/*
* Class: Console
* Method: inputKey
* Signature: ([I)C
*/
JNIEXPORT jchar JNICALL Java_Console_inputKey
(JNIEnv *, jclass, jintArray);
#ifdef __cplusplus
}
#endif
#endif
// FILE: ConsoleImp.cpp ======================
// *** Plaform-specific Header(s)
// *** Here is for Win32
#include <windows.h>
// ***
#include <jni.h>
#include "Console.h"
JNIEXPORT jint JNICALL Java_Console_getMaxRows(JNIEnv *, jclass)
{
CONSOLE_SCREEN_BUFFER_INFO csbi;
::GetConsoleScreenBufferInfo(
::GetStdHandle(STD_OUTPUT_HANDLE), &csbi);
return csbi.dwSize.Y;
}
JNIEXPORT jint JNICALL Java_Console_getMaxCols(JNIEnv *, jclass)
{
CONSOLE_SCREEN_BUFFER_INFO csbi;
::GetConsoleScreenBufferInfo(
::GetStdHandle(STD_OUTPUT_HANDLE), &csbi);
return csbi.dwSize.X;
}
JNIEXPORT void JNICALL Java_Console_cls(JNIEnv *, jclass)
{
COORD coordScreen = { 0, 0 };
CONSOLE_SCREEN_BUFFER_INFO csbi;
DWORD cCharsWritten;
DWORD dwConSize;
HANDLE hConsole = ::GetStdHandle(STD_OUTPUT_HANDLE);
// Get the number of character cells in the current buffer
::GetConsoleScreenBufferInfo(hConsole, &csbi);
// Compute Console size
dwConSize = csbi.dwSize.X * csbi.dwSize.Y;
// Fill the entire screen with blanks
::FillConsoleOutputCharacter(hConsole, (TCHAR) ' ',
dwConSize, coordScreen, &cCharsWritten);
// Get the current text attribute
::GetConsoleScreenBufferInfo(hConsole, &csbi);
// Set the buffer's attributes accordingly
::FillConsoleOutputAttribute(hConsole, csbi.wAttributes,
dwConSize, coordScreen, &cCharsWritten);
// Home the cursor at (0, 0)
::SetConsoleCursorPosition(hConsole, coordScreen);
return;
}
JNIEXPORT jint JNICALL Java_Console_getCurRow(JNIEnv *, jclass)
{
CONSOLE_SCREEN_BUFFER_INFO csbi;
::GetConsoleScreenBufferInfo(
::GetStdHandle(STD_OUTPUT_HANDLE), &csbi);
return csbi.dwCursorPosition.Y;
}
JNIEXPORT jint JNICALL Java_Console_getCurCol(JNIEnv *, jclass)
{
CONSOLE_SCREEN_BUFFER_INFO csbi;
::GetConsoleScreenBufferInfo(
::GetStdHandle(STD_OUTPUT_HANDLE), &csbi);
return csbi.dwCursorPosition.X;
}
JNIEXPORT void JNICALL Java_Console_setCurPos(JNIEnv* env, jclass obj, jint
row, jint col)
{
COORD coord; coord.X = col; coord.Y = row;
::SetConsoleCursorPosition(
::GetStdHandle(STD_OUTPUT_HANDLE), coord);
}
JNIEXPORT jchar JNICALL Java_Console_inputKey(JNIEnv* env, jclass obj,
jintArray keyData)
{
const char NUL = '\0',
ESC = '\x1B';
const int TIMEOUT_MILLIS = 1000;
jsize len = env->GetArrayLength(keyData);
jint* keyData_ = env->GetIntArrayElements(keyData, 0);
DWORD omode, nmode; DWORD itemsRead = 0;
INPUT_RECORD ir;
char inputBuffer[4] = { NUL };
HANDLE hConsole = ::GetStdHandle(STD_INPUT_HANDLE);
::GetConsoleMode(hConsole, &omode);
nmode = omode & ~ENABLE_LINE_INPUT & ~ENABLE_ECHO_INPUT;
::SetConsoleMode(hConsole, nmode);
do
{
::FlushConsoleInputBuffer(hConsole);
::WaitForSingleObject(hConsole, TIMEOUT_MILLIS);
::PeekConsoleInput(hConsole, &ir, 1, &itemsRead);
if (itemsRead > 0)
{
if (ir.EventType == KEY_EVENT)
{
// Discard all non-keydown events
if (ir.Event.KeyEvent.bKeyDown == FALSE)
{
::ReadConsoleInput(hConsole, &ir, 1, &itemsRead);
continue;
}
// Got ASCII key, so extract, flush, and exit
if (ir.Event.KeyEvent.uChar.AsciiChar != NUL)
{
if (ir.Event.KeyEvent.uChar.AsciiChar == ESC)
{
::ReadConsoleInput(hConsole, &ir, 1, &itemsRead);
inputBuffer[0] = ESC;
}
else
::ReadFile(hConsole, inputBuffer, 1, &itemsRead, NULL);
keyData_[0] = ir.Event.KeyEvent.wVirtualKeyCode;
keyData_[1] = ir.Event.KeyEvent.wVirtualScanCode;
break;
}
// Got 'special' key, so determine appropriate actions
switch (ir.Event.KeyEvent.dwControlKeyState)
{
case ENHANCED_KEY:
::ReadConsoleInput(hConsole, &ir, 1, &itemsRead);
break;
case LEFT_ALT_PRESSED: case LEFT_CTRL_PRESSED:
case RIGHT_ALT_PRESSED: case RIGHT_CTRL_PRESSED:
::ReadFile(hConsole, inputBuffer, 1, &itemsRead, NULL);
inputBuffer[0] = NUL;
break;
case SHIFT_PRESSED:
::ReadFile(hConsole, inputBuffer, 1, &itemsRead, NULL);
break;
}
keyData_[0] = ir.Event.KeyEvent.wVirtualKeyCode;
keyData_[1] = ir.Event.KeyEvent.wVirtualScanCode;
}
else
{
// Not Key Event, so just extract and discard
::ReadConsoleInput(hConsole, &ir, 1, &itemsRead);
}
}
} while (itemsRead == 0);
::FlushConsoleInputBuffer(hConsole);
::SetConsoleMode(hConsole, omode);
env->ReleaseIntArrayElements(keyData, keyData_, 0);
return inputBuffer[0];
}
