帮忙看一个简单的关于super的程序
import java.io.*;
public class Grep extends FilterInputStream
{String substring;
DataInputStream in;
public Grep(DataInputStream in,String substring)
{super(in);
this.in=in;
this.substring=substring;
}
public final String readLine( ) throws IOException
{String line;
do
{line=in.readLine( );
}
while(line!=null)&&(line.indexof(substring)==-1);
return line;
}
public void main(String [] args)
{if((args.length==0)||(args.length>2))
{System.out.println("error!");
System.exit(0);
}
try
{DataInputStream d=new DataInputStream(new FilterInputStream(args[1]));
Grep g=new Grep(d,args[0]);
String line;
for(;;)
{line=g.readLine( );
if(line==null)
break;
System.out.println(line);
}
g.close( );
}
catch(IOException e)
System.err.println(e);
}
}
super是当前对象的直接父类,那么super(in);this.in=in是什么功能。
小第刚学,请指教。