public LocationInfo()

in src/main/java/org/apache/log4j/spi/LocationInfo.java [133:246]
85 lines of code
22 McCabe index (conditional complexity)

    public LocationInfo(Throwable t, String fqnOfCallingClass) {
      if(t == null || fqnOfCallingClass == null)
	return;
      if (getLineNumberMethod != null) {
          try {
              Object[] noArgs = null;
              Object[] elements =  (Object[]) getStackTraceMethod.invoke(t, noArgs);
              String prevClass = NA;
              for(int i = elements.length - 1; i >= 0; i--) {
                  String thisClass = (String) getClassNameMethod.invoke(elements[i], noArgs);
                  if(fqnOfCallingClass.equals(thisClass)) {
                      int caller = i + 1;
                      if (caller < elements.length) {
                          className = prevClass;
                          methodName = (String) getMethodNameMethod.invoke(elements[caller], noArgs);
                          fileName = (String) getFileNameMethod.invoke(elements[caller], noArgs);
                          if (fileName == null) {
                              fileName = NA;
                          }
                          int line = ((Integer) getLineNumberMethod.invoke(elements[caller], noArgs)).intValue();
                          if (line < 0) {
                              lineNumber = NA;
                          } else {
                              lineNumber = String.valueOf(line);
                          }
                          StringBuffer buf = new StringBuffer();
                          buf.append(className);
                          buf.append(".");
                          buf.append(methodName);
                          buf.append("(");
                          buf.append(fileName);
                          buf.append(":");
                          buf.append(lineNumber);
                          buf.append(")");
                          this.fullInfo = buf.toString();
                      }
                      return;
                  }
                  prevClass = thisClass;
              }
              return;
          } catch(IllegalAccessException ex) {
              LogLog.debug("LocationInfo failed using JDK 1.4 methods", ex);
          } catch(InvocationTargetException ex) {
              if (ex.getTargetException() instanceof InterruptedException
                      || ex.getTargetException() instanceof InterruptedIOException) {
                  Thread.currentThread().interrupt();
              }
              LogLog.debug("LocationInfo failed using JDK 1.4 methods", ex);
          } catch(RuntimeException ex) {
              LogLog.debug("LocationInfo failed using JDK 1.4 methods", ex);
          }
      }

      String s;
      // Protect against multiple access to sw.
      synchronized(sw) {
	t.printStackTrace(pw);
	s = sw.toString();
	sw.getBuffer().setLength(0);
      }
      //System.out.println("s is ["+s+"].");
      int ibegin, iend;

      // Given the current structure of the package, the line
      // containing "org.apache.log4j.Category." should be printed just
      // before the caller.

      // This method of searching may not be fastest but it's safer
      // than counting the stack depth which is not guaranteed to be
      // constant across JVM implementations.
      ibegin = s.lastIndexOf(fqnOfCallingClass);
      if(ibegin == -1)
	return;

      //
      //   if the next character after the class name exists
      //       but is not a period, see if the classname is
      //       followed by a period earlier in the trace.
      //       Minimizes mistakeningly matching on a class whose
      //       name is a substring of the desired class.
      //       See bug 44888.
      if (ibegin + fqnOfCallingClass.length() < s.length() &&
              s.charAt(ibegin + fqnOfCallingClass.length()) != '.') {
          int i = s.lastIndexOf(fqnOfCallingClass + ".");
          if (i != -1) {
              ibegin = i;
          }
      }


      ibegin = s.indexOf(Layout.LINE_SEP, ibegin);
      if(ibegin == -1)
	return;
      ibegin+= Layout.LINE_SEP_LEN;

      // determine end of line
      iend = s.indexOf(Layout.LINE_SEP, ibegin);
      if(iend == -1)
	return;

      // VA has a different stack trace format which doesn't
      // need to skip the inital 'at'
      if(!inVisualAge) {
	// back up to first blank character
	ibegin = s.lastIndexOf("at ", iend);
	if(ibegin == -1)
	  return;
	// Add 3 to skip "at ";
	ibegin += 3;
      }
      // everything between is the requested stack item
      this.fullInfo = s.substring(ibegin, iend);
    }