client.java

分布式数据库原形代码 可以支持个用户同时登陆到数据库中查询需要的资源

package transaction;

import java.rmi.*;

/** 
 * A client of the Distributed Travel Reservation System.
 * 
 */

public class Client {
    
    public static void main(String args[]) {
	String rmiName = System.getProperty("rmiName");
	if (rmiName == null || rmiName.equals("")) {
	    rmiName = ResourceManager.DefaultRMIName;
	}

	String rmiRegPort = System.getProperty("rmiRegPort");
	if (rmiRegPort != null && !rmiRegPort.equals("")) {
	    rmiName = "//:" + rmiRegPort + "/" + rmiName;
	}

	ResourceManager rm = null;
	try {
	    rm = (ResourceManager)Naming.lookup(rmiName);
	    System.out.println("Bound to RM");
	} 
	catch (Exception e) {
	    System.err.println("Cannot bind to RM:" + e);
	    System.exit(1);
	}

	try {
	    int xid = rm.start();

	    if (!rm.addFlight(xid, "347", 230, 999)) {
		System.err.println("Add flight failed");
	    }
	    if (!rm.addRooms(xid, "SFO", 500, 150)) {
		System.err.println("Add room failed");
	    }
	    
	    System.out.println("Flight 347 has " +
			       rm.queryFlight(xid, "347") +
			       " seats.");
	    if (!rm.reserveFlight(xid, "John", "347")) {
		System.err.println("Reserve flight failed");
	    }
	    System.out.println("Flight 347 now has " +
			       rm.queryFlight(xid, "347") +
			       " seats.");

	    if (!rm.commit(xid)) {
		System.err.println("Commit failed");
	    }

	    /*
	    if (!rm.shutdown()) {
		System.err.println("Shutdown failed");
	    }
	    */
	} 
	catch (Exception e) {
	    System.err.println("Received exception:" + e);
	    System.exit(1);
	}

    }
}