/* * ** Network and Service Differentiation Extensions to GridSim 3.0 ** * * Gokul Poduval & Chen-Khong Tham * Computer Communication Networks (CCN) Lab * Dept of Electrical & Computer Engineering * National University of Singapore * August 2004 * * Licence: GPL - http://www.gnu.org/copyleft/gpl.html * * Packet.java - Interface of a Network Packet. * */package gridsim.net;/** * This the structure for packets.  * * @since GridSim Toolkit 3.1 * @author Gokul Poduval & Chen-Khong Tham, National University of Singapore */public interface Packet{    /**     * Returns a string describing this packet in detail.     * @return description of this packet     * @pre $none     * @post $none     */    String toString();    /**     * Returns the size of this packet     * @return size of the packet     * @pre $none     * @post $none     */    long getSize();    /**     * Sets the size of this packet     * @param size  size of the packet     * @return <tt>true</tt> if it is successful, <tt>false</tt> otherwise     * @pre size >= 0     * @post $none     */    boolean setSize(long size);    /**     * Returns the destination id of this packet.     * @return destination id     * @pre $none     * @post $none     */    int getDestID();    /**     * Returns the ID of this packet     * @return packet ID     * @pre $none     * @post $none     */    int getID();        /**     * Returns the ID of the source of this packet.     * @return source id     * @pre $none     * @post $none     */    int getSrcID();    /**     * Gets the network service type of this packet     * @return the network service type     * @pre $none     * @post $none     */    int getNetServiceType();    /**     * Sets the network service type of this packet.     * <p>     * By default, the service type is 0 (zero). It is depends on the packet     * scheduler to determine the priority of this service level.     * @param serviceType   this packet's service type     * @pre serviceType >= 0     * @post $none     */    void setNetServiceType(int serviceType);    /**     * Gets an entity ID from the last hop that this packet has traversed.     * @return an entity ID     * @pre $none     * @post $none     */    int getLast();    /**     * Sets an entity ID from the last hop that this packet has traversed.     * @param last  an entity ID from the last hop     * @pre last > 0     * @post $none     */    void setLast(int last);    /**     * Gets this packet tag     * @return this packet tag     * @pre $none     * @post $none     */    int getTag();} // end interface