cms/util/ReferenceManager.java

//---PACKAGE DECLARATION---
package uk.ac.ukc.iscream.refman;

//---IMPORTS---
import org.omg.CORBA.ORB;
import org.omg.CosNaming.*;
import org.omg.PortableServer.*;
import uk.ac.ukc.iscream.core.*;

/**
 * This class returns references for global system objects.
 * This class is used to create and return references to objects
 * that are required throughout the system.  Most of which
 * are CORBA based.  It also manages the ORB for the component.
 *
 * It is a singleton object with a static method to obtain a
 * reference to it.  This removes the need for passing
 * references to all the objects it contains throughout 
 * a component.
 *
 * @author  $Author: ajm4 $
 * @version $Id: ReferenceManager.java,v 1.1 2000/11/30 00:54:27 ajm4 Exp $
 */
public class ReferenceManager {

//---FINAL ATTRIBUTES---
   
    /**
     * The current CVS revision of this class
     */
    public final String REVISION = "$Revision: 1.1 $";
    
//---STATIC METHODS---

    /**
     * This creates the single instance of the ReferenceManager by
     * calling the private constructor.  If it is called twice, 
     * it detects an instance already exits and throws an exception.
     *
     * @param args the args to be passed to the ORB
     * @param name the name of the component that will use this singleton
     *
     * @return a reference to the ReferenceManager
     *
     * @throws AlreadyInitialisedException if this method has already been called
     */
    public static ReferenceManager init(String[] args, String name) throws AlreadyInitialisedException {
        if (_instance != null) {
            throw new AlreadyInitialisedException("init has already been called");
        }
        _instance = new ReferenceManager(args, name);
        return _instance;
    }
    
    /**
     * This returns a reference to the single instance of the
     * ReferenceManager.
     *
     * @return a reference to the ReferenceManager
     *
     * @throws NotInitialisedException if the reference manager has not been initialised
     */
    public static ReferenceManager getInstance() throws NotInitialisedException {
        if (_instance == null) {
            throw new NotInitialisedException("attempt to obtain reference when not initialised");
        }
        return _instance;
    }

//---CONSTRUCTORS---

    /**
     * This is a private constructor
     * This ensures that the system performs according to a Singleton design pattern
     *
     * @param args the args to be passed to the ORB
     * @param name the name of the component that will use this singleton
     */
    private ReferenceManager(String[] args, String name) {
        _orb = ORB.init(args, null);
        _name = name;
        getLogger().write(toString(), Logger.SYSINIT, "created");
    }

//---PUBLIC METHODS---

    /**
     * Obtains a CORBA reference through the naming service
     * for the named object.
     * This will throw a RuntimeException if there is an error
     *
     * @param name the name of the CORBA object to resolve
     *
     * @return a reference to the object
     */
    public org.omg.CORBA.Object getCORBARef(String name) {
        org.omg.CORBA.Object objRef = null;
        try {
            objRef = getNS().resolve(getNS().to_name(name));
        } catch (org.omg.CosNaming.NamingContextPackage.CannotProceed e) {
            throw new RuntimeException("\nCRITICAL:Naming Service Cannot Proceed - when resolving reference to " + name + "!\n" + 
                                         "         Please check with your CORBA naming service provider.");
        } catch (org.omg.CosNaming.NamingContextPackage.InvalidName e) {
            throw new RuntimeException("\nCRITICAL:Invalid Name - when resolving reference to " + name + "!\n" + 
                                         "         Please check with your CORBA naming service provider.");
        } catch (org.omg.CosNaming.NamingContextPackage.NotFound e) {
            throw new RuntimeException("\nCRITICAL:Not Found - when resolving reference to " + name + "!\n" + 
                                         "         Please check that this component is running.");
        }
        return objRef;
    }

    /** 
     * Binds a given servant with the given name
     * to the naming service.
     * This will throw a RuntimeException if there is an error
     *
     * @param objRef a reverence to the servant object
     * @param name the name to bind to the naming service with
     */
    public void bindToOrb(org.omg.PortableServer.Servant objRef, String name) {
        try {
            getNS().bind(getNS().to_name(name), getRootPOA().servant_to_reference(objRef));
        } catch (org.omg.PortableServer.POAPackage.WrongPolicy e) {
            throw new RuntimeException("\nCRITICAL:Wrong POA Policy - when binding " + name + "!\n" + 
                                         "         This indicates an error with your ORB.");
        } catch (org.omg.PortableServer.POAPackage.ServantNotActive e) {
            throw new RuntimeException("\nCRITICAL:ServantNotActive - when binding " + name + "!\n" + 
                                         "         This indicates an error with your ORB.");
        } catch (org.omg.CosNaming.NamingContextPackage.InvalidName e) {
            throw new RuntimeException("\nCRITICAL:Invalid Name - when binding " + name + "!\n" + 
                                         "         Please check with your CORBA naming service provider.");
        } catch (org.omg.CosNaming.NamingContextPackage.CannotProceed e) {
            throw new RuntimeException("\nCRITICAL:Naming Service Cannot Proceed - when binding " + name + "!\n" + 
                                         "         Please check with your CORBA naming service provider.");
        } catch (org.omg.CosNaming.NamingContextPackage.NotFound e) {
            throw new RuntimeException("\nCRITICAL:Naming Service Not Found - when binding " + name + "!\n" + 
                                         "         Please check with your CORBA naming service provider.");
        } catch (org.omg.CosNaming.NamingContextPackage.AlreadyBound e) {
            throw new RuntimeException("\nCRITICAL:Already Bound - when binding " + name + "!\n" + 
                                         "         Another component with this name is already running.");
        }
    }
    
    /**
     * Activates the POA
     * This will throw a RuntimeException if there is an error
     */
    public void activatePOA() {
        try {
            getRootPOA().the_POAManager().activate();
        } catch (org.omg.PortableServer.POAManagerPackage.AdapterInactive e) {
            throw new RuntimeException("\nCRITICAL:POA Set Inactive - when trying to activate POA!\n" + 
                                         "         This indicates an error with your ORB.");
        }
    }
    
    /**
     * Overrides the {@link java.lang.Object#toString() Object.toString()}
     * method to provide clean logging (every class should have this).
     *
     * @return the name of this class and its CVS revision
     */
    public String toString() {
        return getName() + "{" + getClass().getName() + "}(" + REVISION.substring(11, REVISION.length() - 2) + ")";
    }

//---PRIVATE METHODS---

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

    /**
     * Returns a reference to the ORB
     *
     * @return the reference this class holds
     */
    public ORB getORB() {
        return _orb;
    }

    /**
     * Returns a reference to the Root POA
     * This will throw a RuntimeException if there is an error
     *
     * @return the reference this class holds
     */
    public POA getRootPOA() {
        if (_rootPOA == null) {
            org.omg.CORBA.Object objRef = null;
            try {
                objRef = getORB().resolve_initial_references("RootPOA");
            } catch (org.omg.CORBA.ORBPackage.InvalidName e) {
                throw new RuntimeException("\nCRITICAL:Unable to resolve reference to the RootPOA!\n" + 
                                             "         This indicates an error with your ORB.");
            }
            _rootPOA = POAHelper.narrow(objRef);
        }
        return _rootPOA;
    }
    
    /**
     * Returns a reference to the Naming Service
     * This will throw a RuntimeException if there is an error
     *
     * @return the reference this class holds
     */
    public NamingContextExt getNS() {
        if (_ns == null) {
            org.omg.CORBA.Object objRef = null;
            try {
                objRef = getORB().resolve_initial_references("NameService");
            } catch (org.omg.CORBA.ORBPackage.InvalidName e) {
                throw new RuntimeException("\nCRITICAL:Unable to resolve reference to the Naming Service!\n" +
                                             "         Please check with your CORBA naming service provider.");
            }
            _ns = NamingContextExtHelper.narrow(objRef);
        }
        return _ns;
    }
    
    /**
     * Returns a reference to the configuration manager
     * This will throw a RuntimeException if there is an error
     *
     * @return the reference this class holds
     */
    public ConfigurationManager getCM() {
        if (_cm == null) {
            _cm = ConfigurationManagerHelper.narrow(getCORBARef("iscream.ConfigurationManager"));
        }
        return _cm;
    }

    /**
     * Returns a reference to the logger
     * This will throw a RuntimeException if there is an error
     *
     * @return the reference this class holds
     */
    public Logger getLogger() {
        if (_logger == null) {
            _logger = LoggerHelper.narrow(getCORBARef("iscream.Logger"));
        }
        return _logger;
    }
    
    /**
     * Returns a reference to the name
     *
     * @return the reference this class holds
     */
    public String getName() {
        return _name;
    }

//---ATTRIBUTES---
    
    /**
     * The ORB
     */
    private ORB _orb;
    
    /**
     * The Naming Service
     */
    private NamingContextExt _ns;
    
    /**
     * The Root POA
     */
    private POA _rootPOA;

    /**
     * The configuration manager
     */
    private ConfigurationManager _cm;

    /**
     * The logger
     */
    private Logger _logger;
    
    /**
     * The name
     */
    private String _name;

//---STATIC ATTRIBUTES---
    
    /**
     * A reference to the single instance of this class
     */
    private static ReferenceManager _instance; 
}
Revision:	1.2
Committed:	Thu Nov 30 02:19:31 2000 UTC (23 years, 5 months ago) by ajm
Branch:	MAIN
Changes since 1.1:	+81 -53 lines
Log Message:	Added more ORB support services
#	Content
1	//---PACKAGE DECLARATION---
2	package uk.ac.ukc.iscream.refman;
3
4	//---IMPORTS---
5	import org.omg.CORBA.ORB;
6	import org.omg.CosNaming.*;
7	import org.omg.PortableServer.*;
8	import uk.ac.ukc.iscream.core.*;
9
10	/**
11	* This class returns references for global system objects.
12	* This class is used to create and return references to objects
13	* that are required throughout the system. Most of which
14	* are CORBA based. It also manages the ORB for the component.
15	*
16	* It is a singleton object with a static method to obtain a
17	* reference to it. This removes the need for passing
18	* references to all the objects it contains throughout
19	* a component.
20	*
21	* @author $Author: ajm4 $
22	* @version $Id: ReferenceManager.java,v 1.1 2000/11/30 00:54:27 ajm4 Exp $
23	*/
24	public class ReferenceManager {
25
26	//---FINAL ATTRIBUTES---
27
28	/**
29	* The current CVS revision of this class
30	*/
31	public final String REVISION = "$Revision: 1.1 $";
32
33	//---STATIC METHODS---
34
35	/**
36	* This creates the single instance of the ReferenceManager by
37	* calling the private constructor. If it is called twice,
38	* it detects an instance already exits and throws an exception.
39	*
40	* @param args the args to be passed to the ORB
41	* @param name the name of the component that will use this singleton
42	*
43	* @return a reference to the ReferenceManager
44	*
45	* @throws AlreadyInitialisedException if this method has already been called
46	*/
47	public static ReferenceManager init(String[] args, String name) throws AlreadyInitialisedException {
48	if (_instance != null) {
49	throw new AlreadyInitialisedException("init has already been called");
50	}
51	_instance = new ReferenceManager(args, name);
52	return _instance;
53	}
54
55	/**
56	* This returns a reference to the single instance of the
57	* ReferenceManager.
58	*
59	* @return a reference to the ReferenceManager
60	*
61	* @throws NotInitialisedException if the reference manager has not been initialised
62	*/
63	public static ReferenceManager getInstance() throws NotInitialisedException {
64	if (_instance == null) {
65	throw new NotInitialisedException("attempt to obtain reference when not initialised");
66	}
67	return _instance;
68	}
69
70	//---CONSTRUCTORS---
71
72	/**
73	* This is a private constructor
74	* This ensures that the system performs according to a Singleton design pattern
75	*
76	* @param args the args to be passed to the ORB
77	* @param name the name of the component that will use this singleton
78	*/
79	private ReferenceManager(String[] args, String name) {
80	_orb = ORB.init(args, null);
81	_name = name;
82	getLogger().write(toString(), Logger.SYSINIT, "created");
83	}
84
85	//---PUBLIC METHODS---
86
87	/**
88	* Obtains a CORBA reference through the naming service
89	* for the named object.
90	* This will throw a RuntimeException if there is an error
91	*
92	* @param name the name of the CORBA object to resolve
93	*
94	* @return a reference to the object
95	*/
96	public org.omg.CORBA.Object getCORBARef(String name) {
97	org.omg.CORBA.Object objRef = null;
98	try {
99	objRef = getNS().resolve(getNS().to_name(name));
100	} catch (org.omg.CosNaming.NamingContextPackage.CannotProceed e) {
101	throw new RuntimeException("\nCRITICAL:Naming Service Cannot Proceed - when resolving reference to " + name + "!\n" +
102	" Please check with your CORBA naming service provider.");
103	} catch (org.omg.CosNaming.NamingContextPackage.InvalidName e) {
104	throw new RuntimeException("\nCRITICAL:Invalid Name - when resolving reference to " + name + "!\n" +
105	" Please check with your CORBA naming service provider.");
106	} catch (org.omg.CosNaming.NamingContextPackage.NotFound e) {
107	throw new RuntimeException("\nCRITICAL:Not Found - when resolving reference to " + name + "!\n" +
108	" Please check that this component is running.");
109	}
110	return objRef;
111	}
112
113	/**
114	* Binds a given servant with the given name
115	* to the naming service.
116	* This will throw a RuntimeException if there is an error
117	*
118	* @param objRef a reverence to the servant object
119	* @param name the name to bind to the naming service with
120	*/
121	public void bindToOrb(org.omg.PortableServer.Servant objRef, String name) {
122	try {
123	getNS().bind(getNS().to_name(name), getRootPOA().servant_to_reference(objRef));
124	} catch (org.omg.PortableServer.POAPackage.WrongPolicy e) {
125	throw new RuntimeException("\nCRITICAL:Wrong POA Policy - when binding " + name + "!\n" +
126	" This indicates an error with your ORB.");
127	} catch (org.omg.PortableServer.POAPackage.ServantNotActive e) {
128	throw new RuntimeException("\nCRITICAL:ServantNotActive - when binding " + name + "!\n" +
129	" This indicates an error with your ORB.");
130	} catch (org.omg.CosNaming.NamingContextPackage.InvalidName e) {
131	throw new RuntimeException("\nCRITICAL:Invalid Name - when binding " + name + "!\n" +
132	" Please check with your CORBA naming service provider.");
133	} catch (org.omg.CosNaming.NamingContextPackage.CannotProceed e) {
134	throw new RuntimeException("\nCRITICAL:Naming Service Cannot Proceed - when binding " + name + "!\n" +
135	" Please check with your CORBA naming service provider.");
136	} catch (org.omg.CosNaming.NamingContextPackage.NotFound e) {
137	throw new RuntimeException("\nCRITICAL:Naming Service Not Found - when binding " + name + "!\n" +
138	" Please check with your CORBA naming service provider.");
139	} catch (org.omg.CosNaming.NamingContextPackage.AlreadyBound e) {
140	throw new RuntimeException("\nCRITICAL:Already Bound - when binding " + name + "!\n" +
141	" Another component with this name is already running.");
142	}
143	}
144
145	/**
146	* Activates the POA
147	* This will throw a RuntimeException if there is an error
148	*/
149	public void activatePOA() {
150	try {
151	getRootPOA().the_POAManager().activate();
152	} catch (org.omg.PortableServer.POAManagerPackage.AdapterInactive e) {
153	throw new RuntimeException("\nCRITICAL:POA Set Inactive - when trying to activate POA!\n" +
154	" This indicates an error with your ORB.");
155	}
156	}
157
158	/**
159	* Overrides the {@link java.lang.Object#toString() Object.toString()}
160	* method to provide clean logging (every class should have this).
161	*
162	* @return the name of this class and its CVS revision
163	*/
164	public String toString() {
165	return getName() + "{" + getClass().getName() + "}(" + REVISION.substring(11, REVISION.length() - 2) + ")";
166	}
167
168	//---PRIVATE METHODS---
169
170	//---ACCESSOR/MUTATOR METHODS---
171
172	/**
173	* Returns a reference to the ORB
174	*
175	* @return the reference this class holds
176	*/
177	public ORB getORB() {
178	return _orb;
179	}
180
181	/**
182	* Returns a reference to the Root POA
183	* This will throw a RuntimeException if there is an error
184	*
185	* @return the reference this class holds
186	*/
187	public POA getRootPOA() {
188	if (_rootPOA == null) {
189	org.omg.CORBA.Object objRef = null;
190	try {
191	objRef = getORB().resolve_initial_references("RootPOA");
192	} catch (org.omg.CORBA.ORBPackage.InvalidName e) {
193	throw new RuntimeException("\nCRITICAL:Unable to resolve reference to the RootPOA!\n" +
194	" This indicates an error with your ORB.");
195	}
196	_rootPOA = POAHelper.narrow(objRef);
197	}
198	return _rootPOA;
199	}
200
201	/**
202	* Returns a reference to the Naming Service
203	* This will throw a RuntimeException if there is an error
204	*
205	* @return the reference this class holds
206	*/
207	public NamingContextExt getNS() {
208	if (_ns == null) {
209	org.omg.CORBA.Object objRef = null;
210	try {
211	objRef = getORB().resolve_initial_references("NameService");
212	} catch (org.omg.CORBA.ORBPackage.InvalidName e) {
213	throw new RuntimeException("\nCRITICAL:Unable to resolve reference to the Naming Service!\n" +
214	" Please check with your CORBA naming service provider.");
215	}
216	_ns = NamingContextExtHelper.narrow(objRef);
217	}
218	return _ns;
219	}
220
221	/**
222	* Returns a reference to the configuration manager
223	* This will throw a RuntimeException if there is an error
224	*
225	* @return the reference this class holds
226	*/
227	public ConfigurationManager getCM() {
228	if (_cm == null) {
229	_cm = ConfigurationManagerHelper.narrow(getCORBARef("iscream.ConfigurationManager"));
230	}
231	return _cm;
232	}
233
234	/**
235	* Returns a reference to the logger
236	* This will throw a RuntimeException if there is an error
237	*
238	* @return the reference this class holds
239	*/
240	public Logger getLogger() {
241	if (_logger == null) {
242	_logger = LoggerHelper.narrow(getCORBARef("iscream.Logger"));
243	}
244	return _logger;
245	}
246
247	/**
248	* Returns a reference to the name
249	*
250	* @return the reference this class holds
251	*/
252	public String getName() {
253	return _name;
254	}
255
256	//---ATTRIBUTES---
257
258	/**
259	* The ORB
260	*/
261	private ORB _orb;
262
263	/**
264	* The Naming Service
265	*/
266	private NamingContextExt _ns;
267
268	/**
269	* The Root POA
270	*/
271	private POA _rootPOA;
272
273	/**
274	* The configuration manager
275	*/
276	private ConfigurationManager _cm;
277
278	/**
279	* The logger
280	*/
281	private Logger _logger;
282
283	/**
284	* The name
285	*/
286	private String _name;
287
288	//---STATIC ATTRIBUTES---
289
290	/**
291	* A reference to the single instance of this class
292	*/
293	private static ReferenceManager _instance;
294	}