/**
*
*/
package leo.demo.training;
/**
* Get current java file name and current code line number
* @author Leo Xie
*/
public class CurrentLine {
  /**
  * @param args
  */
  public static void main(String[] args) {
    StackTraceElement ste1 = null;
    // get current thread and its related stack trace
    StackTraceElement[] steArray = Thread.currentThread().getStackTrace();
    int steArrayLength = steArray.length;
    String s = null;
    // output all related info of the existing stack traces
    if(steArrayLength==0) {
      System.err.println("No Stack Trace.");
    } else {
      for (int i=0; i<steArrayLength; i++) {
        System.out.println("Stack Trace-" + i);
        ste1 = steArray[i];
        s = ste1.getFileName() + ": Line " + ste1.getLineNumber();
        System.out.println(s);
      }
    }
    // the following code segment will output the line number of the "new " clause
    // that's to say the line number of "StackTraceElement ste2 = new Throwable().getStackTrace()[0];"
    StackTraceElement ste2 = new Throwable().getStackTrace()[0];
    System.out.println(ste2.getFileName() + ": Line " + ste2.getLineNumber());
    // the following clause will output the line number in the external method "getLineInfo()"
    System.out.println(getLineInfo());
    // the following clause will output its current line number
    System.out.println(getLineInfo(new Throwable().getStackTrace()[0]));
  }
  /**
  * return current java file name and code line number
  * @return String
  */
  public static String getLineInfo() {
    StackTraceElement ste3 = new Throwable().getStackTrace()[0];
    return (ste3.getFileName() + ": Line " + ste3.getLineNumber());
  }
  /**
  * return current java file name and code line name
  * @return String
  */
  public static String getLineInfo(StackTraceElement ste4) {
    return (ste4.getFileName() + ": Line " + (ste4.getLineNumber()));
  }
}