cms/util/ReferenceManager.java

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

//---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 1.4 2000/11/30 03:07:25 ajm4 Exp $
 */
public class ReferenceManager {

//---FINAL ATTRIBUTES---
   
    /**
     * The current CVS revision of this class
     */
    public final String REVISION = "$Revision: 1.4 $";
    
//---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;
    }

//---PUBLIC METHODS---

    /**
     * Obtains a CORBA reference through the naming service
     * for the named object.
     * This will throw a Error 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 Error("\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 Error("\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 Error("\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 Error 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 Error("\nCRITICAL:Wrong POA Policy - when binding " + name + "!\n" + 
                              "         This indicates an error with your ORB.");
        } catch (org.omg.PortableServer.POAPackage.ServantNotActive e) {
            throw new Error("\nCRITICAL:ServantNotActive - when binding " + name + "!\n" + 
                              "         This indicates an error with your ORB.");
        } catch (org.omg.CosNaming.NamingContextPackage.InvalidName e) {
            throw new Error("\nCRITICAL:Invalid Name - when binding " + name + "!\n" + 
                              "         Please check with your CORBA naming service provider.");
        } catch (org.omg.CosNaming.NamingContextPackage.CannotProceed e) {
            throw new Error("\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 Error("\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 Error("\nCRITICAL:Already Bound - when binding " + name + "!\n" + 
                              "         Another component with this name is already running.");
        }
    }
    
    /**
     * Activates the POA
     * This will throw a Error if there is an error
     */
    public void activatePOA() {
        try {
            getRootPOA().the_POAManager().activate();
        } catch (org.omg.PortableServer.POAManagerPackage.AdapterInactive e) {
            throw new Error("\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 Error 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 Error("\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 Error 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 Error("\nCRITICAL:Unable to resolve reference to the Naming Service!\n" +
                                  "         Please check with your CORBA naming service provider.");
            }
            _ns = NamingContextExtHelper.narrow(objRef);
        }
        // check we managed to talk to the naming service
        if (_ns == null) {
            throw new Error("\nCRITICAL:Unable to resolve reference to the Naming Service!\n" +
                              "         Please check with your CORBA naming service provider.");
        }
        return _ns;
    }
    
    /**
     * Returns a reference to the configuration manager
     * This will throw a Error if there is an error
     *
     * @return the reference this class holds
     */
    public ConfigurationManager getCM() {
        if (_cm == null) {
            _cm = ConfigurationManagerHelper.narrow(getCORBARef("iscream.ConfigurationManager"));
        }
        // check we managed to talk to the configuration manager
        if (_cm == null) {
            throw new Error("\nCRITICAL:Unable to resolve reference to the Configuration Manager!\n" +
                              "         Please check with your CORBA naming service provider.");
        }
        return _cm;
    }

    /**
     * Returns a reference to the logger
     * This will throw a Error 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;
    }

    /**
     * Sets the reference to the name
     *
     * @param the new name
     */
    public void setName(String name) {
        _name = name;
    }
    
    /**
     * 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:	1.5
Committed:	Mon Dec 11 16:38:09 2000 UTC (23 years, 4 months ago) by ajm
Branch:	MAIN
Changes since 1.4:	+43 -34 lines
Log Message:	Changed the Runtimes to Errors...as these are what they are! Still stack traces though, which I don't like.
#	User	Rev	Content
1	ajm	1.1	//---PACKAGE DECLARATION---
2	ajm	1.3	package uk.ac.ukc.iscream.util;
3	ajm	1.1
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	ajm	1.2	* are CORBA based. It also manages the ORB for the component.
15	ajm	1.1	*
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	ajm	1.2	* @author $Author: ajm4 $
22	ajm	1.5	* @version $Id: ReferenceManager.java,v 1.4 2000/11/30 03:07:25 ajm4 Exp $
23	ajm	1.1	*/
24			public class ReferenceManager {
25
26			//---FINAL ATTRIBUTES---
27
28			/**
29			* The current CVS revision of this class
30			*/
31	ajm	1.5	public final String REVISION = "$Revision: 1.4 $";
32	ajm	1.1
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			}
83
84			//---PUBLIC METHODS---
85
86			/**
87	ajm	1.2	* Obtains a CORBA reference through the naming service
88			* for the named object.
89	ajm	1.5	* This will throw a Error if there is an error
90	ajm	1.2	*
91			* @param name the name of the CORBA object to resolve
92			*
93			* @return a reference to the object
94			*/
95			public org.omg.CORBA.Object getCORBARef(String name) {
96			org.omg.CORBA.Object objRef = null;
97			try {
98			objRef = getNS().resolve(getNS().to_name(name));
99			} catch (org.omg.CosNaming.NamingContextPackage.CannotProceed e) {
100	ajm	1.5	throw new Error("\nCRITICAL:Naming Service Cannot Proceed - when resolving reference to " + name + "!\n" +
101			" Please check with your CORBA naming service provider.");
102	ajm	1.2	} catch (org.omg.CosNaming.NamingContextPackage.InvalidName e) {
103	ajm	1.5	throw new Error("\nCRITICAL:Invalid Name - when resolving reference to " + name + "!\n" +
104			" Please check with your CORBA naming service provider.");
105	ajm	1.2	} catch (org.omg.CosNaming.NamingContextPackage.NotFound e) {
106	ajm	1.5	throw new Error("\nCRITICAL:Not Found - when resolving reference to " + name + "!\n" +
107			" Please check that this component is running.");
108	ajm	1.2	}
109			return objRef;
110			}
111
112			/**
113			* Binds a given servant with the given name
114			* to the naming service.
115	ajm	1.5	* This will throw a Error if there is an error
116	ajm	1.2	*
117			* @param objRef a reverence to the servant object
118			* @param name the name to bind to the naming service with
119			*/
120			public void bindToOrb(org.omg.PortableServer.Servant objRef, String name) {
121			try {
122			getNS().bind(getNS().to_name(name), getRootPOA().servant_to_reference(objRef));
123			} catch (org.omg.PortableServer.POAPackage.WrongPolicy e) {
124	ajm	1.5	throw new Error("\nCRITICAL:Wrong POA Policy - when binding " + name + "!\n" +
125			" This indicates an error with your ORB.");
126	ajm	1.2	} catch (org.omg.PortableServer.POAPackage.ServantNotActive e) {
127	ajm	1.5	throw new Error("\nCRITICAL:ServantNotActive - when binding " + name + "!\n" +
128			" This indicates an error with your ORB.");
129	ajm	1.2	} catch (org.omg.CosNaming.NamingContextPackage.InvalidName e) {
130	ajm	1.5	throw new Error("\nCRITICAL:Invalid Name - when binding " + name + "!\n" +
131			" Please check with your CORBA naming service provider.");
132	ajm	1.2	} catch (org.omg.CosNaming.NamingContextPackage.CannotProceed e) {
133	ajm	1.5	throw new Error("\nCRITICAL:Naming Service Cannot Proceed - when binding " + name + "!\n" +
134			" Please check with your CORBA naming service provider.");
135	ajm	1.2	} catch (org.omg.CosNaming.NamingContextPackage.NotFound e) {
136	ajm	1.5	throw new Error("\nCRITICAL:Naming Service Not Found - when binding " + name + "!\n" +
137			" Please check with your CORBA naming service provider.");
138	ajm	1.2	} catch (org.omg.CosNaming.NamingContextPackage.AlreadyBound e) {
139	ajm	1.5	throw new Error("\nCRITICAL:Already Bound - when binding " + name + "!\n" +
140			" Another component with this name is already running.");
141	ajm	1.2	}
142			}
143
144			/**
145			* Activates the POA
146	ajm	1.5	* This will throw a Error if there is an error
147	ajm	1.2	*/
148			public void activatePOA() {
149			try {
150			getRootPOA().the_POAManager().activate();
151			} catch (org.omg.PortableServer.POAManagerPackage.AdapterInactive e) {
152	ajm	1.5	throw new Error("\nCRITICAL:POA Set Inactive - when trying to activate POA!\n" +
153			" This indicates an error with your ORB.");
154	ajm	1.2	}
155			}
156
157			/**
158	ajm	1.1	* Overrides the {@link java.lang.Object#toString() Object.toString()}
159			* method to provide clean logging (every class should have this).
160			*
161			* @return the name of this class and its CVS revision
162			*/
163			public String toString() {
164			return getName() + "{" + getClass().getName() + "}(" + REVISION.substring(11, REVISION.length() - 2) + ")";
165			}
166
167			//---PRIVATE METHODS---
168
169			//---ACCESSOR/MUTATOR METHODS---
170
171			/**
172			* Returns a reference to the ORB
173			*
174			* @return the reference this class holds
175			*/
176			public ORB getORB() {
177			return _orb;
178			}
179
180			/**
181			* Returns a reference to the Root POA
182	ajm	1.5	* This will throw a Error if there is an error
183	ajm	1.1	*
184			* @return the reference this class holds
185			*/
186			public POA getRootPOA() {
187			if (_rootPOA == null) {
188			org.omg.CORBA.Object objRef = null;
189			try {
190			objRef = getORB().resolve_initial_references("RootPOA");
191			} catch (org.omg.CORBA.ORBPackage.InvalidName e) {
192	ajm	1.5	throw new Error("\nCRITICAL:Unable to resolve reference to the RootPOA!\n" +
193			" This indicates an error with your ORB.");
194	ajm	1.1	}
195			_rootPOA = POAHelper.narrow(objRef);
196			}
197			return _rootPOA;
198			}
199
200			/**
201			* Returns a reference to the Naming Service
202	ajm	1.5	* This will throw a Error if there is an error
203	ajm	1.1	*
204			* @return the reference this class holds
205			*/
206			public NamingContextExt getNS() {
207			if (_ns == null) {
208			org.omg.CORBA.Object objRef = null;
209			try {
210			objRef = getORB().resolve_initial_references("NameService");
211			} catch (org.omg.CORBA.ORBPackage.InvalidName e) {
212	ajm	1.5	throw new Error("\nCRITICAL:Unable to resolve reference to the Naming Service!\n" +
213			" Please check with your CORBA naming service provider.");
214	ajm	1.1	}
215			_ns = NamingContextExtHelper.narrow(objRef);
216			}
217	ajm	1.5	// check we managed to talk to the naming service
218			if (_ns == null) {
219			throw new Error("\nCRITICAL:Unable to resolve reference to the Naming Service!\n" +
220			" Please check with your CORBA naming service provider.");
221			}
222	ajm	1.1	return _ns;
223			}
224
225			/**
226			* Returns a reference to the configuration manager
227	ajm	1.5	* This will throw a Error if there is an error
228	ajm	1.1	*
229			* @return the reference this class holds
230			*/
231			public ConfigurationManager getCM() {
232			if (_cm == null) {
233	ajm	1.2	_cm = ConfigurationManagerHelper.narrow(getCORBARef("iscream.ConfigurationManager"));
234	ajm	1.1	}
235	ajm	1.5	// check we managed to talk to the configuration manager
236			if (_cm == null) {
237			throw new Error("\nCRITICAL:Unable to resolve reference to the Configuration Manager!\n" +
238			" Please check with your CORBA naming service provider.");
239			}
240	ajm	1.1	return _cm;
241			}
242
243			/**
244			* Returns a reference to the logger
245	ajm	1.5	* This will throw a Error if there is an error
246	ajm	1.1	*
247			* @return the reference this class holds
248			*/
249			public Logger getLogger() {
250			if (_logger == null) {
251	ajm	1.2	_logger = LoggerHelper.narrow(getCORBARef("iscream.Logger"));
252	ajm	1.1	}
253			return _logger;
254	ajm	1.4	}
255
256			/**
257			* Sets the reference to the name
258			*
259			* @param the new name
260			*/
261			public void setName(String name) {
262			_name = name;
263	ajm	1.1	}
264
265			/**
266			* Returns a reference to the name
267			*
268			* @return the reference this class holds
269			*/
270			public String getName() {
271			return _name;
272			}
273
274			//---ATTRIBUTES---
275
276			/**
277			* The ORB
278			*/
279			private ORB _orb;
280
281			/**
282			* The Naming Service
283			*/
284			private NamingContextExt _ns;
285
286			/**
287			* The Root POA
288			*/
289			private POA _rootPOA;
290
291			/**
292			* The configuration manager
293			*/
294			private ConfigurationManager _cm;
295
296			/**
297			* The logger
298			*/
299			private Logger _logger;
300
301			/**
302			* The name
303			*/
304			private String _name;
305
306			//---STATIC ATTRIBUTES---
307
308			/**
309			* A reference to the single instance of this class
310			*/
311			private static ReferenceManager _instance;
312			}