PID.java

package lsr.common;

/**
 * Keeps data related with replica like id, hostname and port numbers required
 * for replicas to communicate with each other, and by clients to connect to
 * replicas.
 */
public class PID {
    private final String hostname;
    private final int replicaPort;
    private final int clientPort;
    private final int id;

    /**
     * Creates new process identifier.
     * 
     * @param id - process id
     * @param hostname - name of host used to connect to this process
     * @param replicaPort - port number used by other replicas
     * @param clientPort - port number used by clients
     */
    public PID(int id, String hostname, int replicaPort, int clientPort) {
        if (hostname == null) {
            throw new NullPointerException("Hostname field cannot be null");
        }
        this.id = id;
        this.clientPort = clientPort;
        this.hostname = hostname;
        this.replicaPort = replicaPort;
    }

    /**
     * Returns the hostname used by replicas and clients to connect.
     * 
     * @return the name of host
     */
    public String getHostname() {
        return hostname;
    }

    /**
     * Return the port number used by other replicas to connect to this replica.
     * 
     * @return port number
     */
    public int getReplicaPort() {
        return replicaPort;
    }

    /**
     * Returns the port number used by client to connect to this replica.
     * 
     * @return port number
     */
    public int getClientPort() {
        return clientPort;
    }

    /**
     * Returns unique id of this replica.
     * 
     * @return process id
     */
    public int getId() {
        return id;
    }

    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj == null || (obj.getClass() != this.getClass())) {
            return false;
        }

        PID pid = (PID) obj;
        return hostname.equals(pid.hostname) && replicaPort == pid.replicaPort;
    }

    public int hashCode() {
        int hash = 7;
        hash = 31 * hash + hostname.hashCode();
        hash = 31 * hash + replicaPort;
        hash = 31 * hash + clientPort;
        hash = 31 * hash + id;
        return hash;
    }

    public String toString() {
        return "[p" + id + "] " + hostname + ", ports = (replica=" + replicaPort + ", client=" +
               clientPort + ")";
    }
}