handler.java

aglet的部分源码

package com.ibm.maf.rmi;

/*
 * @(#)Handler.java
 * 
 * IBM Confidential-Restricted
 * 
 * OCO Source Materials
 * 
 * 03L7246 (c) Copyright IBM Corp. 1996, 1998
 * 
 * The source code for this program is not published or otherwise
 * divested of its trade secrets, irrespective of what has been
 * deposited with the U.S. Copyright Office.
 */

import com.ibm.maf.*;
import com.ibm.aglet.Ticket;
import com.ibm.awb.misc.Resource;

import java.security.AccessController;
import java.security.PrivilegedExceptionAction;
import java.security.PrivilegedActionException;
import java.net.URL;
import java.net.InetAddress;
import java.net.MalformedURLException;
import java.net.UnknownHostException;
import java.util.Hashtable;
import java.util.Enumeration;
import java.rmi.*;
import java.rmi.registry.*;

public class Handler implements AgentSystemHandler {

	private static final int DEFAULT_PORT = 4434;

	static Hashtable rmi_agentsystems = new Hashtable();

	static boolean initialized = false;

	static private int MAX_RETRY = 3;

	public MAFAgentSystem getMAFAgentSystem(Ticket ticket) 
			throws java.net.UnknownHostException {

		// tentative
		java.net.URL u = ticket.getDestination();
		String address = u.getHost();

		address += (u.getPort() == -1 ? "" : (":" + u.getPort()));

		return getMAFAgentSystem0(address);
	}
	public MAFAgentSystem getMAFAgentSystem(String address) 
			throws java.net.UnknownHostException {

		int to = -1;

		if (address.startsWith("//") == true) {
			address = address.substring(2);
			to = address.indexOf('/');

		} else if (address.startsWith("/")) {
			address = address.substring(1);
			to = address.indexOf('/');

		} else {
			to = address.indexOf('/');

		} 

		if (to >= 0) {
			address = address.substring(0, to);
		} 

		return getMAFAgentSystem0(address);
	}
	private MAFAgentSystem getMAFAgentSystem0(String address) 
			throws java.net.UnknownHostException {
		MAFAgentSystem local = 
			MAFAgentSystem_RMIImpl.getLocalAgentSystem(address);

		if (local != null) {
			return local;
		} 
		synchronized (rmi_agentsystems) {
			MAFAgentSystem_RMI rmi = 
				(MAFAgentSystem_RMI)rmi_agentsystems.get(address);

			if (rmi == null) {
				try {
					final String fAddress = address;

					rmi = 
						(MAFAgentSystem_RMI)AccessController
							.doPrivileged(new PrivilegedExceptionAction() {
						public Object run() 
								throws UnknownHostException, 
									   MalformedURLException, 
									   NotBoundException, RemoteException {
							return Naming.lookup("//" + fAddress + "/aglets");
						} 
					});
					rmi_agentsystems.put(address, rmi);
				} catch (PrivilegedActionException ex) {
					Exception e = ex.getException();

					if (e instanceof UnknownHostException) {
						throw (UnknownHostException)e;
					} else if (e instanceof MalformedURLException) {
						throw new UnknownHostException(e.getMessage());
					} else if (e instanceof NotBoundException) {
						e.printStackTrace();
						return null;
					} else if (e instanceof RemoteException) {
						e.printStackTrace();
						return null;
					} else {
						ex.printStackTrace();
					} 
				} catch (Exception ex) {
					ex.printStackTrace();
				} 
			} 
			return MAFAgentSystem_RMIClient.find_maf_agentsystem(rmi, 
					address);
		} 
	}
	synchronized public void initMAFAgentSystem(MAFAgentSystem local) 
			throws MAFExtendedException {
		try {
			if (initialized) {
				return;
			} 
			initialized = true;

			String hostname = InetAddress.getLocalHost().getHostName();

			java.util.Properties sys_props = System.getProperties();
			String s_port = 
				sys_props.getProperty("maf.port", 
									  String.valueOf(DEFAULT_PORT));
			int port;

			try {
				port = Integer.parseInt(s_port);
			} catch (NumberFormatException ex) {
				port = DEFAULT_PORT;
				System.err.println("maf.port must be a number, use " 
								   + DEFAULT_PORT);
			} 
			sys_props.put("maf.port", String.valueOf(port));

			// Resource sys_res = Resource.getResourceFor("system");
			// int port = sys_res.getInteger("maf.port", DEFAULT_PORT);

			// Resource res = Resource.getResourceFor("aglets");
			// int default_port = res.getInteger("aglets.defaultport", DEFAULT_PORT);
			// int port = res.getInteger("aglets.port", default_port);
			local.setAddress("rmi://" + hostname + ":" + port);
		} catch (Exception ex) {
			throw new MAFExtendedException(ex.toString());
		} 
	}
	/* package synchronized */
	static MAFAgentSystem_RMI rebind(MAFAgentSystem_RMI rmi) {
		if (rmi_agentsystems.contains(rmi) == false) {
			return null;
		} 

		Enumeration e = rmi_agentsystems.keys();

		while (e.hasMoreElements()) {
			String address = (String)e.nextElement();
			Object obj = rmi_agentsystems.get(address);

			if (obj == rmi) {
				System.out.println("rebind found.. " + address);
				String name = "//" + address + "/aglets";
				int num_retry = 1;

				while (num_retry++ < MAX_RETRY) {
					try {
						MAFAgentSystem_RMI new_rmi = 
							(MAFAgentSystem_RMI)Naming.lookup(name);

						rmi_agentsystems.put(address, new_rmi);
						return new_rmi;
					} catch (Exception ex) {
						try {
							Thread.currentThread().sleep(1);
						} catch (InterruptedException exx) {
							return null;
						} 
					} 
				} 
			} 
		} 
		return null;
	}
	public void startMAFAgentSystem(MAFAgentSystem local) 
			throws MAFExtendedException {
		try {
			MAFAgentSystem_RMIImpl impl = new MAFAgentSystem_RMIImpl(local);

			URL url = new URL(local.getAddress());
			Registry reg = LocateRegistry.createRegistry(url.getPort());

			reg.bind("aglets", impl);

			// Register "local"(MAFAgentSystem) to MAFFinder server.
			try {
				MAFFinder finder = local.get_MAFFinder();

				if (finder != null) {
					try {
						AgentSystemInfo asi = local.get_agent_system_info();
						String addr = local.getAddress();

						finder.register_agent_system(asi.agent_system_name, 
													 addr, asi);
					} catch (Exception ex) {
						ex.printStackTrace();
					} 
				} 
			} catch (FinderNotFound ex) {}
		} catch (Exception ex) {
			throw new MAFExtendedException(ex.toString());
		} 
	}
}