Question

I am reading a data in byte-by-byte. when i have determined that i have an entire message, i need to pass it to another function as a string. Some messages can be quite large, but the sizes vary frequently. Which implementation do you all feel is most effecient:

public test class
{
   char[] buffer = new char[MAX_SIZE_7200];
   int bufferIndex = 0;
   void parseData(ArrayList<Byte> msg, length)
   {
       while (!msg.isEmpty())
       {
          buffer[bufferIndex++] = (char) msg.remove(0);
          if (isfullmessage)
          {
             parseData(new String(buffer, 0, bufferIndex);
             bufferIndex = 0;  //restart and continue parsing data
          }
       }
   }
 }

OR:

public test class
{
   List<Character> buffer = new ArrayList<Character>();
   int bufferIndex = 0;
   void parseData(ArrayList<Byte> msg, length)
   {
       while (!msg.isEmpty())
       {
          buffer.add((char) msg.remove(0));
          if (isfullmessage)
          {
              StringBuilder builder = new StringBuilder(buffer.size());
              for (Character ch: buffer)
              {
                  builder.append(ch);
              }
              parseData(builder.toString());
              buffer.clear();
          }
       }
   }
 }  

OR:

public test class
    {
       StringBuilder buffer = new StringBuilder();
       int bufferIndex = 0;
       void parseData(ArrayList<Byte> msg, length)
       {
           while (!msg.isEmpty())
           {
              buffer.append((char) msg.remove(0));
              if (isfullmessage)
              {                  
                  parseData(builder.toString());
                  buffer.clear();  //some stringbuilder clear function
              }
           }
       }
     }  

or is there a more efficient way. Please note that i have the variables holding my finished message outside the scope of the function since i might process data that does not contain a full message and may take multiple executions of the function to get a full message and process it.

Answer 1

Use StringBuilder. It supports appending characters one at a time, expands capacity as needed, and can be reset for reuse purposes.