/*
 *  Salamander Transport Layer
 *
 *    Michael J. Willis    (violator@umich.edu)
 *
 * $Workfile: SalPacket.java $
 *   $Author: rmalan $
 *     $Date: 1997/07/16 02:22:30 $
 * $Revision: 1.4 $
 */
package Salamander;

import java.net.*;
import java.io.*;

/**
 * The SalPacket is the basic unit of information transferred from the
 * server to the SalDataQueue object specified in SalConnection.startDataFlow().
 * It contains a SalProperties object, which specifies the properties of the
 * packet, and a data buffer that can be read from using the getInputStream()
 * method.
 */
public class SalPacket    {

    public SalPacket()    {
        m_props = new SalProperties();
        setLength("0");
    }
    /**
     * Header containing all properties of this packet
     */
    SalProperties    m_props;


    /**
     * Key containing name of service that produced this object
     */
    static final String NAME = "NAME";

    /**
     * Key containing timestamp of creating of this packet
     */
    static final String TIMESTAMP = "TIMESTAMP";

    /**
     * Key containing method name
     */
    static final String METHOD = "COMMAND";

    static final String OBJ_SIZE = "OBJ_SIZE";

    /**
     * "Raw" data being sent
     */
    byte            m_data[];

    /**
     * Returns an InputStream object that can be used to read the raw data
     * out of this packet.  The length of this InputStream can be obtained
     * with the getLength() method, though the stream will generate end-of-file
     * when the data has been read.
     * @returns An InputStream to the data, or <em>null<\em> if getLength() is 0.
     */
    public InputStream getInputStream()   {
      int length = getLength();
      if (length == 0) return null;

      if (length != m_data.length) // somthing's rotton in the state...
        return null;

      return (InputStream) new ByteArrayInputStream(m_data);
    }


    /**
     * Writes to the m_data buffer. Need some way to publish data through the
     * java interface
     */

    public void setData (byte[] inBytes) {
      m_data = new byte [inBytes.length];
      for (int i = 0; i < inBytes.length; i++)
          m_data[i] = inBytes[i];

      Integer len = new Integer (inBytes.length);
      m_props.setProperty ("OBJ_SIZE", len.toString());
    }


    /**
     * Returns number of bytes in the data portion of this packet
     */
    int getLength()       {
      int i = 0;
      try {
        String size = (String) m_props.get(OBJ_SIZE);
        // System.out.println("Size of packet is : "+size);
        i = Integer.parseInt( size );
      } catch (Exception e)       {
        SAL.trace("Caught a sneeze\n");
        SAL.trace("Exception: "+e);
        m_props.serialize(new DataOutputStream(System.err));
        return 0;
      }

      return i;
    }


    /**
     * Returns a reference to the SalProperties object associated with
     * this packet.
     * @returns SalProperties object
     */
    public SalProperties getProperties()    {
        return m_props;
    }

    public void setProperties(SalProperties p)    {
        m_props = p;
    }

    /**
     * @returns The name of the service that produced this object
     */
    public String getName()    {
        return (String) m_props.get(NAME);
    }

    /**
     * @returns The timestamp of this packet
     */
    public String getTimeStamp()    {
        return (String) m_props.get(TIMESTAMP);
    }

    /**
     * @returns the method of this packet
     */
    public String getMethod()    {
        return (String) m_props.get(METHOD);
    }

    /**
     * @param name The name of the service producing the related SalPacket
     */
    public void setName(String name)    {
        m_props.setProperty(NAME, name);
    }

    public void setLength(String length)    {
        m_props.setProperty(OBJ_SIZE, length);
    }

    public int getPropLength() {
        return (m_props.getLength());
    }
    
    /**
     * @param time The timestamp of this packet
     */
    public void setTimeStamp(String time)    {
        m_props.setProperty(TIMESTAMP, time);
    }

    /**
     * @param method The method for this packet
     */
    public void setMethod(String method)    {
        m_props.setProperty(METHOD, method);
    }

    public DataOutputStream serialize(DataOutputStream out)
    throws IOException    {
        m_props.serialize(out);
        if (null != m_data) out.write(m_data);

        return out;
    }

    public DataInputStream serialize(DataInputStream in)
    throws IOException    {
        m_props.serialize(in);
        int len = getLength();
        m_data = new byte[len];
        SAL.trace("reading in "+len+" bytes...");
        for (int i=0;i<len;i++)
            m_data[i] = (byte)in.read();

        return in;
    }
}