to locate a mobile position in a plane i use 3 fixed ultrasonic transducers which are HIGH when receiving a us pulse from the mobile. arduino sends serially the corresponding sets of data, value1, 2 and 3 to processing.
to get the mobile coordinates i need to measure the time during which transducer 1 being HIGH transducer 2 is still LOW: t12 and similarly t13 and t23.
Now, i need an advice: is there something wrong with the code below? in particular is it possible to have a while() inside an if()?

 // importing the processing serial class
 import processing.serial.*;
// variables for serial connection, portname and baudrate have to be set
 Serial port;  
 int value = 0;
// buffer and value variable for each value and boolean to switch between values
 String bufA="", bufB="", bufC="";  
 int buf;  // integer switch to distinguish values
int value1, value2, value3;  
 int t,ta,tb,tc,t12,t13,t23;  
// lets user control DisplayItems properties, value output and drawing attributes
void setup(){
 // set size and framerate
 frameRate(10);
 // establish serial port connection      
 port = new Serial(this, Serial.list()[2], 9600);
 println(port);
}
// reads the serial events, stores events in buffer and asigns values
void serialEvent(int serial){
 if(serial!=10) {      
     if (serial=='A') buf = 1;
     if (serial=='B') buf = 2;
     if (serial=='C') buf = 3;
     if (buf==1){ if (serial!='A') bufA += char(serial);
               }else if (buf == 2){
               if (serial!='B') bufB+= char(serial);
               }else if (buf == 3){
               if (serial!='C') bufC+= char(serial);
               }
     } else {
               if (buf == 1){  value1 = int(bufA); bufA="";
               } else if (buf == 2){ value2 = int(bufB); bufB="";
               }else if (buf == 3){ value3 = int(bufC); bufC="";
               }
     }      
}
void draw(){
// listen to serial port and trigger serial event    
 while(port.available() > 0){
       value = port.read();
       serialEvent(value);
  }
t = millis();
if(value1 > 300 && value2 < 300 && value3 < 300){
while(value1 > 300 && value2 < 300 && value3 < 300){
ta = millis() - t;
}
if(value2 < 300){
  t13 = ta;
  }
   if(value3 < 300){
  t12 = ta;
  }
}
else if(value2 > 300 && value1 < 300 && value3 < 300){
while(value2 > 300 && value1 < 300 && value3 < 300){
tb = millis() - t;
}
if(value1 < 300){
  t23 = tb;
  }
   if(value3 < 300){
  t12 = -tb;
  }
}
else if(value3 > 300 && value2 < 300 && value1 < 300){
while(value3 > 300 && value2 < 300 && value1 < 300){
tc = millis() - t;
}
if(value2 < 300){
  t13 = -tc;
  }
   if(value1 < 300){
  t23 = -tc;
  }
}

   println("t12: "+t12+" - t13: "+t13+ " - t23: "+t23);
}

thanks!

oh, and: sure you can put a while inside if ..