experimental/agents/AgentStation.java

//---PACKAGE DECLARATION---

//---IMPORTS---
import java.net.Socket;
import java.io.IOException;
import java.util.ArrayList;

/**
 * An implementation of an agent station
 *
 * @author  $Author: tdb1 $
 * @version $Id: TemplateClass.java,v 1.11 2001/03/22 21:50:41 tdb1 Exp $
 */
class AgentStation extends Station {

//---FINAL / FINAL STATIC ATTRIBUTES---

    /**
     * The current CVS revision of this class
     */
    public static final String REVISION = "$Revision: 1.11 $";
    
    public static final int DIRECT_LISTEN_PORT = 32497;
    
    public static final int PEER_LISTEN_PORT = 32498;
    
//---STATIC METHODS---
   
    /**
     * Returns a reference to the singleton agent station in use
     *
     * @throws RuntimeException if not yet initialised
     */
    public static AgentStation getInstance() throws RuntimeException {
        if (_instance == null) {
            throw new RuntimeException("Cannot obtain instance to uninitialised AgentStation!");
        }
        return _instance;
    }

    /**
     * Constructs and returns the singleton AgentStation class
     *
     * @throws RuntimeException if already initialised
     */
    public static AgentStation initialise(String name, String descriptiveName, String initialPeerHostname, int initialPeerPort) {
        if (_instance != null) {
            throw new RuntimeException("Already initialised!");
        }
        _instance = new AgentStation(name, descriptiveName, initialPeerHostname, initialPeerPort);
        return _instance;
    }
    
//---CONSTRUCTORS---

    /**
     * Starts up the agent station.
     * This is a private method to ensure singleton pattern.
     */
    private AgentStation(String name, String descriptiveName, String initialPeerHostname, int initialPeerPort) {
        _name = name;
        _descriptiveName = descriptiveName;
        
        DirectAgentHandlerFactory directAgentHandlerFactory = new DirectAgentHandlerFactory();
        PeerHandlerFactory peerHandlerFactory = new PeerHandlerFactory();
        
        Listener directAgentListener = new Listener(DIRECT_LISTEN_PORT, directAgentHandlerFactory);
        Listener peerListener = new Listener(PEER_LISTEN_PORT, peerHandlerFactory);
        
        directAgentListener.start();
        peerListener.start();
        
        // TESTING ONLY - Have one peer connection
        if (initialPeerHostname != null) {
            try {
                _logger.write(toString(), Logger.DEBUG, "Establishing peer connection with - " + initialPeerHostname + ":" + initialPeerPort);
                Socket socket = new Socket(initialPeerHostname, initialPeerPort);
        
                PeerHandler peerHandler = new PeerHandler(socket);
                addPeer(peerHandler);
            } catch (IOException e) {
                _logger.write(toString(), Logger.ERROR, "I/O ERROR - " + e);
            }
        }    
        _logger.write(toString(), Logger.SYSINIT, "created");
    }

//---PUBLIC METHODS---

    //*** STATION SERVICES TO AGENTS ***
    
    public ArrayList getAllAgents() {
        return _agentList;
    }
    
    public ArrayList getAllPeers() {
        return _peerList;
    }
    
    public String getName() {
        return _name + " - " + _descriptiveName;
    }
    
    public void sendAgent(Agent agent, PeerHandler peerHandler) {
        // NOTE - no support for restarting agent on a failed send.
        agent.shutdown();
        ((PeerHandler) _peerList.get(_peerList.indexOf(peerHandler))).sendAgent(agent);
    }
    
    //*** OTHER PUBLIC METHODS ***

    public void addAgent(Agent agent) {
        _logger.write(toString(), Logger.DEBUG, "registered agent");
        _agentList.add(agent);
    }
    
    public void removeAgent(Agent agent) {
        _agentList.remove(_agentList.indexOf(agent));
        _logger.write(toString(), Logger.DEBUG, "deregistered agent");
    }
    
    public void addPeer(PeerHandler peerHandler) {
        _logger.write(toString(), Logger.DEBUG, "registered peer");
        _peerList.add(peerHandler);
    }
    
    public void removePeer(PeerHandler peerHandler) {
        _peerList.remove(peerHandler);
        _logger.write(toString(), Logger.DEBUG, "deregistered peer");
    }

    /**
     * Overrides the {@link java.lang.Object#toString() Object.toString()}
     * method to provide clean logging (every class should have this).
     *
     * This uses the uk.ac.ukc.iscream.util.FormatName class
     * to format the toString()
     *
     * @return the name of this class and its CVS revision
     */
    public String toString() {
        return FormatName.getName(
            _name,
            getClass().getName(),
            REVISION);
    }

//---PRIVATE/PROTECTED METHODS---

//---ACCESSOR/MUTATOR METHODS---

//---ATTRIBUTES---

    /**
     * This is the friendly identifier of the
     * component this class is running in.
     * eg, a Filter may be called "filter1",
     * If this class does not have an owning
     * component,  a name from the configuration
     * can be placed here.  This name could also
     * be changed to null for utility classes.
     */
    private String _name;

    /**
     * This holds a reference to the
     * system logger that is being used.
     */
    private Logger _logger = Logger.getInstance();
    
    private String _descriptiveName;
    
    private ArrayList _agentList = new ArrayList();
    
    private ArrayList _peerList = new ArrayList();

//---STATIC ATTRIBUTES---

    /**
     * Holds the reference to the singleton instance of his class
     */
    private static AgentStation _instance;
    

}
Revision:	1.2
Committed:	Fri May 4 02:04:35 2001 UTC (23 years, 7 months ago) by ajm
Branch:	MAIN
Changes since 1.1:	+170 -46 lines
Log Message:	Loads of new framework but far from complete. The BasicAgent class is as it says, a basic agent, with ability to be run from the command line to fire it into an agentstation. AgentStations now have support for adding and removing agents and support for multiple listeners. Also initial support for peer agent stations. Attempted support at peer -> peer agent transfer, but run into problems. Still no bytecode transfer, but location and method has been figured out. The AgentSystem class is now the bootstrap class for an agent station. It brings up the AgentStation (which is now singleton) and the Logger (also singleton - using standard i-scream logging techniques). It is possible to specify a peer station that the booting agent station should connect to. Initial TODO: agent class loader agent bytecode transfer solve peer -> peer problems - possibly by creating extra socket to send agent, but shouldn't really be needed
#	User	Rev	Content
1	ajm	1.2	//---PACKAGE DECLARATION---
2	ajm	1.1
3	ajm	1.2	//---IMPORTS---
4			import java.net.Socket;
5			import java.io.IOException;
6			import java.util.ArrayList;
7
8			/**
9			* An implementation of an agent station
10			*
11			* @author $Author: tdb1 $
12			* @version $Id: TemplateClass.java,v 1.11 2001/03/22 21:50:41 tdb1 Exp $
13			*/
14	ajm	1.1	class AgentStation extends Station {
15	ajm	1.2
16			//---FINAL / FINAL STATIC ATTRIBUTES---
17
18			/**
19			* The current CVS revision of this class
20			*/
21			public static final String REVISION = "$Revision: 1.11 $";
22
23			public static final int DIRECT_LISTEN_PORT = 32497;
24
25			public static final int PEER_LISTEN_PORT = 32498;
26
27			//---STATIC METHODS---
28
29			/**
30			* Returns a reference to the singleton agent station in use
31			*
32			* @throws RuntimeException if not yet initialised
33			*/
34			public static AgentStation getInstance() throws RuntimeException {
35			if (_instance == null) {
36			throw new RuntimeException("Cannot obtain instance to uninitialised AgentStation!");
37			}
38			return _instance;
39			}
40
41			/**
42			* Constructs and returns the singleton AgentStation class
43			*
44			* @throws RuntimeException if already initialised
45			*/
46			public static AgentStation initialise(String name, String descriptiveName, String initialPeerHostname, int initialPeerPort) {
47			if (_instance != null) {
48			throw new RuntimeException("Already initialised!");
49			}
50			_instance = new AgentStation(name, descriptiveName, initialPeerHostname, initialPeerPort);
51			return _instance;
52			}
53	ajm	1.1
54	ajm	1.2	//---CONSTRUCTORS---
55
56			/**
57			* Starts up the agent station.
58			* This is a private method to ensure singleton pattern.
59			*/
60			private AgentStation(String name, String descriptiveName, String initialPeerHostname, int initialPeerPort) {
61			_name = name;
62			_descriptiveName = descriptiveName;
63
64			DirectAgentHandlerFactory directAgentHandlerFactory = new DirectAgentHandlerFactory();
65			PeerHandlerFactory peerHandlerFactory = new PeerHandlerFactory();
66
67			Listener directAgentListener = new Listener(DIRECT_LISTEN_PORT, directAgentHandlerFactory);
68			Listener peerListener = new Listener(PEER_LISTEN_PORT, peerHandlerFactory);
69
70			directAgentListener.start();
71			peerListener.start();
72
73			// TESTING ONLY - Have one peer connection
74			if (initialPeerHostname != null) {
75			try {
76			_logger.write(toString(), Logger.DEBUG, "Establishing peer connection with - " + initialPeerHostname + ":" + initialPeerPort);
77			Socket socket = new Socket(initialPeerHostname, initialPeerPort);
78	ajm	1.1
79	ajm	1.2	PeerHandler peerHandler = new PeerHandler(socket);
80			addPeer(peerHandler);
81			} catch (IOException e) {
82			_logger.write(toString(), Logger.ERROR, "I/O ERROR - " + e);
83			}
84			}
85			_logger.write(toString(), Logger.SYSINIT, "created");
86	ajm	1.1	}
87	ajm	1.2
88			//---PUBLIC METHODS---
89
90			//* STATION SERVICES TO AGENTS *
91	ajm	1.1
92			public ArrayList getAllAgents() {
93			return _agentList;
94			}
95
96	ajm	1.2	public ArrayList getAllPeers() {
97			return _peerList;
98			}
99
100	ajm	1.1	public String getName() {
101	ajm	1.2	return _name + " - " + _descriptiveName;
102	ajm	1.1	}
103
104	ajm	1.2	public void sendAgent(Agent agent, PeerHandler peerHandler) {
105			// NOTE - no support for restarting agent on a failed send.
106			agent.shutdown();
107			((PeerHandler) _peerList.get(_peerList.indexOf(peerHandler))).sendAgent(agent);
108			}
109
110			//* OTHER PUBLIC METHODS *
111
112			public void addAgent(Agent agent) {
113			_logger.write(toString(), Logger.DEBUG, "registered agent");
114			_agentList.add(agent);
115			}
116
117			public void removeAgent(Agent agent) {
118			_agentList.remove(_agentList.indexOf(agent));
119			_logger.write(toString(), Logger.DEBUG, "deregistered agent");
120			}
121
122			public void addPeer(PeerHandler peerHandler) {
123			_logger.write(toString(), Logger.DEBUG, "registered peer");
124			_peerList.add(peerHandler);
125			}
126
127			public void removePeer(PeerHandler peerHandler) {
128			_peerList.remove(peerHandler);
129			_logger.write(toString(), Logger.DEBUG, "deregistered peer");
130			}
131
132			/**
133			* Overrides the {@link java.lang.Object#toString() Object.toString()}
134			* method to provide clean logging (every class should have this).
135			*
136			* This uses the uk.ac.ukc.iscream.util.FormatName class
137			* to format the toString()
138			*
139			* @return the name of this class and its CVS revision
140			*/
141			public String toString() {
142			return FormatName.getName(
143			_name,
144			getClass().getName(),
145			REVISION);
146			}
147
148			//---PRIVATE/PROTECTED METHODS---
149
150			//---ACCESSOR/MUTATOR METHODS---
151
152			//---ATTRIBUTES---
153
154			/**
155			* This is the friendly identifier of the
156			* component this class is running in.
157			* eg, a Filter may be called "filter1",
158			* If this class does not have an owning
159			* component, a name from the configuration
160			* can be placed here. This name could also
161			* be changed to null for utility classes.
162			*/
163			private String _name;
164
165			/**
166			* This holds a reference to the
167			* system logger that is being used.
168			*/
169			private Logger _logger = Logger.getInstance();
170
171			private String _descriptiveName;
172
173	ajm	1.1	private ArrayList _agentList = new ArrayList();
174	ajm	1.2
175			private ArrayList _peerList = new ArrayList();
176
177			//---STATIC ATTRIBUTES---
178
179			/**
180			* Holds the reference to the singleton instance of his class
181			*/
182			private static AgentStation _instance;
183
184
185	ajm	1.1	}