I'm trying to run a C application in Java using ProcessBuilder and the .getInputStream(). Which I think gets this application's output? Then I think I need to use a FileReader wrapped in a BufferedReader? I'm unsure how to connect the Process and the FileReader?
I'm translating some C (in the comments):
void run(){
//FILE *POINTS;
//I think the above points to the file? so I'm using a InputStream object.
private InputStream POINTS;
//generate octree for this case
//=============================
//sprintf(befehl,"%soconv -f %s %s %s \"%s\" > %s\n","",material_file, BlindRadianceFiles_Combined, geometry_file, sun_rad, octree);
//note I've replaced "befehl" with "cmd".
String.format(cmd, "%soconv -f %s %s %s \"%s\" > %s\n","",material_file, BlindRadianceFiles_Combined, geometry_file, sun_rad, octree);
//POINTS = popen(befehl,"r");
//Info on POPEN in C. For instance, if you wanted to read the output of your program, you'd use popen("program", "r"). On the other hand, if you want to write to its input, you would use popen("program", "w").
Process process = new ProcessBuilder(cmd).start();
POINTS = process.getInputStream();
//while( fscanf( POINTS, "%s", buf ) != EOF )
// printf("%s \n",buf);
//pclose(POINTS);
BufferedReader in = new BufferedReader(new FileReader("<filename>"));
while ((in = fileReader.readLine()) != null){
System.out.printf("%s \n", buf);
}
POINTS.close();
UPDATE: below:
I've now got the following, does this seem to make sense? There are 2 different C programs which based on the commands generate files and perform some specific calculations.
void run_oconv_and_rtrace() throws IOException{
String line;
String cmd = null;
//generate octree for this case
//=============================
//TODO review how the command is generated and what information is required for this analysis
cmd = String.format(cmd,"%soconv -f %s %s %s \"%s\" > %s\n","", material_file, BlindRadianceFiles_Combined, geometry_file, sun_rad, octree);
/* Use the processbuilder to run an external process (ie. Radiance C program).
* process.getOutputStream(): return the standard input of the external program. (ie. Java writes to Process).
* process.getInputStream(): return the standard output of the external program. (ie. Jave reads from Process).
*/
ProcessBuilder builder = new ProcessBuilder(cmd);
builder.redirectErrorStream(true); //adds error stream to inputstream
Process process = builder.start();
OutputStream POINTS_FROM_JAVA_TO_C = process.getOutputStream();
InputStream POINTS_FROM_C_TO_JAVA = process.getInputStream();
//BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(POINTS_FROM_JAVA_TO_C));
BufferedReader reader = new BufferedReader(new InputStreamReader(POINTS_FROM_C_TO_JAVA));
//Read output of Radiance:
while ((line = reader.readLine()) != null){
System.out.printf("%s \n", buf);
}
//////////////////////////
// run rtrace and calcualte the shading status for this case
//==========================================================
//TODO review command
cmd = null;
cmd = String.format(cmd, "rtrace_dc -ab 0 -h -lr 6 -dt 0 \"%s\" < %s > %s\n",octree,long_sensor_file[BlindGroupIndex],dir_tmp_filename[NumberOfBlindGroupCombinations]);
builder = new ProcessBuilder(cmd);
builder.redirectErrorStream(true); //adds error stream to inputstream
process = builder.start();
POINTS_FROM_C_TO_JAVA = process.getInputStream();
reader = new BufferedReader(new InputStreamReader(POINTS_FROM_C_TO_JAVA));
//Read output of Radiance:
while ((line = reader.readLine()) != null){
System.out.printf("%s \n", buf);
}
//delete files
//HERE WE NEED TO DELETE THE OCTREE FILES CREATED!
BlindGroupNumberForThisCombination[NumberOfBlindGroupCombinations]=BlindGroupIndex;
NumberOfBlindGroupCombinations++;
}
