I will have to be using JavaCompilers in the near future so I am trying to learn about the basics now and choose the best one to learn and I have come across a question that i could not really fine an answer to online
At the moment im looking at the JavaCompiler. If i have a program X being evaluated and it takes input from System.in and prints output to System.out, can I compile and run it while feeding it some specific input and capturing it's output in a file?
If so, is there any examples online so i can try understand it a bit better?
EDIT:
Simple Test case to pass in while compiling
import java.util.Iterator;
public class TestSet
{
public static void main(String[] args)
{
try
{
System.out.print( "[1]--constructor 1, size, isEmpty: ");
LinkedSet<String> s1 = new LinkedSet<String>();
if (s1.size() != 0)
System.out.print("*** size? ***");
if (!s1.isEmpty())
System.out.print("*** isEmpty? ***");
System.out.println();
}
catch(Exception e)
{
System.out.println("*** CRASH !!! ***");
}
try
{
System.out.print( "[2]--constructor 2, size, isEmpty: ");
LinkedSet<String> s1 = new LinkedSet<String>( "alpha");
if (s1.size() != 1)
System.out.print("*** size? ***");
if (s1.isEmpty())
System.out.print("*** isEmpty? ***");
System.out.println();
}
catch(Exception e)
{
System.out.println("*** CRASH !!! ***");
}
try
{
System.out.print( "[3]--contains: ");
LinkedSet<String> s1 = new LinkedSet<String>("alpha");
if (!s1.contains("alpha"))
System.out.print("*** elt. not found ***");
if (s1.contains("beta"))
System.out.print("*** non-elt ``found'' ***");
System.out.println();
}
catch(Exception e)
{
System.out.println("*** CRASH !!! ***");
}
try
{
System.out.print( "[4]--add: ");
LinkedSet<String> s1 = new LinkedSet<String>();
s1.add("alpha");
s1.add("beta");
s1.add("gamma");
if (s1.size() != 3)
System.out.print("*** size? ***");
if (!s1.contains("alpha") ||
!s1.contains("beta") ||
!s1.contains("gamma"))
System.out.print("*** elt. not found ***");
if (s1.contains("delta"))
System.out.print("*** non-elt ``found'' ***");
s1.add("beta");
if (s1.size() != 3)
System.out.print("*** size/duplicates? ***");
System.out.println();
}
catch(Exception e)
{
System.out.println("*** CRASH !!! ***");
}
try
{
System.out.print( "[5]--remove: ");
LinkedSet<String> s1 = new LinkedSet<String>();
s1.add("alpha");
s1.add("beta");
s1.add("gamma");
s1.remove("beta");
s1.remove("alpha");
s1.remove("gamma");
if (s1.size() != 0)
System.out.print("*** size? ***");
if (s1.contains("alpha") ||
s1.contains("beta") ||
s1.contains("gamma"))
System.out.print("*** non elt. ``found'' ***");
System.out.println();
}
catch(Exception e)
{
System.out.println("*** CRASH !!! ***");
}
try
{
System.out.print( "[6]--print: ");
LinkedSet<String> s1 = new LinkedSet<String>();
s1.add("this");
s1.add("is");
s1.add("assignment");
s1.add("four");
s1.print();
}
catch(Exception e)
{
System.out.println("*** CRASH !!! ***");
}
try
{
System.out.print( "[7]--addAll: ");
LinkedSet<String> s1 = new LinkedSet<String>();
s1.add("alpha");
s1.add("beta");
s1.add("gamma");
LinkedSet<String> s2 = new LinkedSet<String>();
s2.add("beta");
s2.add("delta");
s1.addAll(s2);
if (!s1.contains("alpha") || ! s1.contains("beta") ||
!s1.contains("gamma") || !s1.contains("delta"))
System.out.print("*** elt. ``dropped'' ***");
if (s1.size() != 4)
System.out.print("*** size ? ***");
System.out.println();
}
catch(Exception e)
{
System.out.println("*** CRASH !!! ***");
}
try
{
System.out.print( "[8]--containsAll: ");
LinkedSet<String> s1 = new LinkedSet<String>();
s1.add("alpha");
s1.add("beta");
s1.add("gamma");
LinkedSet<String> s2 = new LinkedSet<String>();
s2.add("beta");
s2.add("delta");
if (s1.containsAll(s2))
System.out.print("*** non-containment incorrect ***");
LinkedSet<String> s3 = new LinkedSet<String>();
s3.add("beta");
s3.add("alpha");
if (!s1.containsAll(s3))
System.out.print("*** containment incorrect ***");
System.out.println();
}
catch(Exception e)
{
System.out.println("*** CRASH !!! ***");
}
try
{
System.out.print( "[9]--removeAll: ");
LinkedSet<String> s1 = new LinkedSet<String>();
s1.add("alpha");
s1.add("beta");
s1.add("gamma");
s1.add("delta");
LinkedSet<String> s2 = new LinkedSet<String>();
s2.add("beta");
s2.add("delta");
s1.removeAll(s2);
if (s1.contains("beta") || s1.contains("delta"))
System.out.print("*** some elts not removed? ***");
if (!s1.contains("alpha") || !s1.contains("gamma"))
System.out.print("*** wrong elts removed? ***");
System.out.println();
}
catch(Exception e)
{
System.out.println("*** CRASH !!! ***");
}
try
{
System.out.print( "[10]--retainAll: ");
LinkedSet<String> s1 = new LinkedSet<String>();
s1.add("alpha");
s1.add("beta");
s1.add("gamma");
s1.add("delta");
LinkedSet<String> s2 = new LinkedSet<String>();
s2.add("beta");
s2.add("delta");
s1.retainAll(s2);
if (s1.contains("alpha") || s1.contains("gamma"))
System.out.print("*** wrong elts retained? ***");
if (!s1.contains("beta") || !s1.contains("delta"))
System.out.print("*** wrong elts removed? ***");
System.out.println();
}
catch(Exception e)
{
System.out.println("*** CRASH !!! ***");
}
try
{
System.out.print( "[11]--elements: ");
LinkedSet<String> s1 = new LinkedSet<String>();
s1.add("alpha");
s1.add("beta");
s1.add("gamma");
s1.add("delta");
Iterator<String> list = s1.elements();
System.out.print("("+list.hasNext()+") ");
if (list.hasNext())
System.out.print(list.next()+"; ");
System.out.print("("+list.hasNext()+")");
if (list.hasNext())
System.out.print(list.next()+"; ");
System.out.print("("+list.hasNext()+")");
if (list.hasNext())
System.out.print(list.next()+"; ");
System.out.print("("+list.hasNext()+")");
if (list.hasNext())
System.out.print(list.next()+"; ");
System.out.print("("+list.hasNext()+")");
if (list.hasNext())
System.out.print(list.next()+"; ");
System.out.println();
}
catch(Exception e)
{
System.out.println("*** CRASH !!! ***");
}
}
}
Ya you can......
1. Are you talking about the command line arguments, if yes then its possible..
Eg:
javac Test.java
enter code herejava Test Hello // Hello is the Input
In Java this "Hello" input is sent to the main() method in it String[] array.
public static void main(String[] args)
So to access this Hello which you have passed as an Argument to the main() methods parameter, you need to do this..
String s = args[0];
2. Now if you want to write this into a file internally from within the program do this.
String s = args[0];
File f = new File(d:\\vivek.txt);
FileWriter fw = new FileWriter(f);
BufferedWriter bw = new BufferedWriter(fw);
bw.write(s);