/**
    *
    */
   package javax.jmdns.impl;
   
   import java.util.ArrayList;
   import java.util.Collection;
   import java.util.Collections;
   import java.util.LinkedList;
  import java.util.List;
  
  import javax.jmdns.impl.constants.DNSConstants;
  
  /**
   * DNSMessage define a DNS message either incoming or outgoing.
   * 
   * @author Werner Randelshofer, Rick Blair, Pierre Frisch
   */
  public abstract class DNSMessage {
  
      /**
       *
       */
      public static final boolean       MULTICAST = true;
  
      /**
       *
       */
      public static final boolean       UNICAST   = false;
  
      // protected DatagramPacket _packet;
      // protected int _off;
      // protected int _len;
      // protected byte[] _data;
  
      private int                       _id;
  
      boolean                           _multicast;
  
      private int                       _flags;
  
      protected final List<DNSQuestion> _questions;
  
      protected final List<DNSRecord>   _answers;
  
      protected final List<DNSRecord>   _authoritativeAnswers;
  
      protected final List<DNSRecord>   _additionals;
  
      /**
       * @param flags
       * @param id
       * @param multicast
       */
      protected DNSMessage(int flags, int id, boolean multicast) {
          super();
          _flags = flags;
          _id = id;
          _multicast = multicast;
          _questions = Collections.synchronizedList(new LinkedList<DNSQuestion>());
          _answers = Collections.synchronizedList(new LinkedList<DNSRecord>());
          _authoritativeAnswers = Collections.synchronizedList(new LinkedList<DNSRecord>());
          _additionals = Collections.synchronizedList(new LinkedList<DNSRecord>());
      }
  
      // public DatagramPacket getPacket() {
      // return _packet;
      // }
      //
      // public int getOffset() {
      // return _off;
      // }
      //
      // public int getLength() {
      // return _len;
      // }
      //
      // public byte[] getData() {
      // if ( _data == null ) _data = new byte[DNSConstants.MAX_MSG_TYPICAL];
      // return _data;
      // }
  
      /**
       * @return message id
       */
      public int getId() {
          return (_multicast ? 0 : _id);
      }
  
      /**
       * @param id
       *            the id to set
       */
      public void setId(int id) {
          this._id = id;
      }
  
      /**
       * @return message flags
      */
     public int getFlags() {
         return _flags;
     }
 
     /**
      * @param flags
      *            the flags to set
      */
     public void setFlags(int flags) {
         this._flags = flags;
     }
 
     /**
      * @return true if multicast
      */
     public boolean isMulticast() {
         return _multicast;
     }
 
     /**
      * @return list of questions
      */
     public Collection<? extends DNSQuestion> getQuestions() {
         return _questions;
     }
 
     /**
      * @return number of questions in the message
      */
     public int getNumberOfQuestions() {
         return this.getQuestions().size();
     }
 
     public Collection<? extends DNSRecord> getAllAnswers() {
         List<DNSRecord> aList = new ArrayList<DNSRecord>(_answers.size() + _authoritativeAnswers.size() + _additionals.size());
         aList.addAll(_answers);
         aList.addAll(_authoritativeAnswers);
         aList.addAll(_additionals);
         return aList;
     }
 
     /**
      * @return list of answers
      */
     public Collection<? extends DNSRecord> getAnswers() {
         return _answers;
     }
 
     /**
      * @return number of answers in the message
      */
     public int getNumberOfAnswers() {
         return this.getAnswers().size();
     }
 
     /**
      * @return list of authorities
      */
     public Collection<? extends DNSRecord> getAuthorities() {
         return _authoritativeAnswers;
     }
 
     /**
      * @return number of authorities in the message
      */
     public int getNumberOfAuthorities() {
         return this.getAuthorities().size();
     }
 
     /**
      * @return list of additional answers
      */
     public Collection<? extends DNSRecord> getAdditionals() {
         return _additionals;
     }
 
     /**
      * @return number of additional in the message
      */
     public int getNumberOfAdditionals() {
         return this.getAdditionals().size();
     }
 
     /**
      * Check if the message is truncated.
      * 
      * @return true if the message was truncated
      */
     public boolean isTruncated() {
         return (_flags & DNSConstants.FLAGS_TC) != 0;
     }
 
     /**
      * Check if the message is a query.
      * 
      * @return true is the message is a query
      */
     public boolean isQuery() {
         return (_flags & DNSConstants.FLAGS_QR_MASK) == DNSConstants.FLAGS_QR_QUERY;
     }
 
     /**
      * Check if the message is a response.
      * 
      * @return true is the message is a response
      */
     public boolean isResponse() {
         return (_flags & DNSConstants.FLAGS_QR_MASK) == DNSConstants.FLAGS_QR_RESPONSE;
     }
 
     /**
      * Check if the message is empty
      * 
      * @return true is the message is empty
      */
     public boolean isEmpty() {
         return (this.getNumberOfQuestions() + this.getNumberOfAnswers() + this.getNumberOfAuthorities() + this.getNumberOfAdditionals()) == 0;
     }
 
     /**
      * Debugging.
      */
     String print() {
         StringBuffer buf = new StringBuffer(200);
         buf.append(this.toString());
         buf.append("\n");
         for (DNSQuestion question : _questions) {
             buf.append("\tquestion:      ");
             buf.append(question);
             buf.append("\n");
         }
         for (DNSRecord answer : _answers) {
             buf.append("\tanswer:        ");
             buf.append(answer);
             buf.append("\n");
         }
         for (DNSRecord answer : _authoritativeAnswers) {
             buf.append("\tauthoritative: ");
             buf.append(answer);
             buf.append("\n");
         }
         for (DNSRecord answer : _additionals) {
             buf.append("\tadditional:    ");
             buf.append(answer);
             buf.append("\n");
         }
         return buf.toString();
     }
 
     /**
      * Debugging.
      * 
      * @param data
      * @return data dump
      */
     protected String print(byte[] data) {
         StringBuilder buf = new StringBuilder(4000);
         for (int off = 0, len = data.length; off < len; off += 32) {
             int n = Math.min(32, len - off);
             if (off < 0x10) {
                 buf.append(' ');
             }
             if (off < 0x100) {
                 buf.append(' ');
             }
             if (off < 0x1000) {
                 buf.append(' ');
             }
             buf.append(Integer.toHexString(off));
             buf.append(':');
             int index = 0;
             for (index = 0; index < n; index++) {
                 if ((index % 8) == 0) {
                     buf.append(' ');
                 }
                 buf.append(Integer.toHexString((data[off + index] & 0xF0) >> 4));
                 buf.append(Integer.toHexString((data[off + index] & 0x0F) >> 0));
             }
             // for incomplete lines
             if (index < 32) {
                 for (int i = index; i < 32; i++) {
                     if ((i % 8) == 0) {
                         buf.append(' ');
                     }
                     buf.append("  ");
                 }
             }
             buf.append("    ");
             for (index = 0; index < n; index++) {
                 if ((index % 8) == 0) {
                     buf.append(' ');
                 }
                 int ch = data[off + index] & 0xFF;
                 buf.append(((ch > ' ') && (ch < 127)) ? (char) ch : '.');
             }
             buf.append("\n");
 
             // limit message size
             if (off + 32 >= 2048) {
                 buf.append("....\n");
                 break;
             }
         }
         return buf.toString();
     }
 
 }