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 1.8 2000/12/13 13:42:50 ajm4 Exp $
 */
public class ReferenceManager {

//---FINAL ATTRIBUTES---
   
    /**
     * The current CVS revision of this class
     */
    public final String REVISION = "$Revision: 1.8 $";
    
//---STATIC METHODS---

    /**
     * This returns a reference to the single instance of the
     * ReferenceManager.
     *
     * This creates the single instance of the ReferenceManager
     * if it does not exist by calling the private constructor.
     *
     * @return a reference to the ReferenceManager
     */
    public static ReferenceManager getInstance() {
        if (_instance == null) {
            _instance = new ReferenceManager();
        }
        return _instance;
    }

//---CONSTRUCTORS---

    /**
     * This is a private constructor
     * This ensures that the system performs according to a Singleton design pattern
     */
    private ReferenceManager() {
        _orb = ORB.init(new String[] {}, null);
    }

//---PUBLIC METHODS---

    /**
     * Obtains a CORBA reference through the naming service
     * for the named object.
     * Calls the dieWithError() if any exceptions happen!
     *
     * @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) {
            dieWithError("\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) {
            dieWithError("\nCRITICAL:Invalid Name - when resolving reference to " + name + "!\n" + 
                              "         Please check with your CORBA naming service provider.");
        } catch (org.omg.CosNaming.NamingContextPackage.NotFound e) {
            dieWithError("\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.
     * Calls the dieWithError() if any exceptions happen!
     *
     * @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) {
            dieWithError("\nCRITICAL:Wrong POA Policy - when binding " + name + "!\n" + 
                              "         This indicates an error with your ORB.");
        } catch (org.omg.PortableServer.POAPackage.ServantNotActive e) {
            dieWithError("\nCRITICAL:ServantNotActive - when binding " + name + "!\n" + 
                              "         This indicates an error with your ORB.");
        } catch (org.omg.CosNaming.NamingContextPackage.InvalidName e) {
            dieWithError("\nCRITICAL:Invalid Name - when binding " + name + "!\n" + 
                              "         Please check with your CORBA naming service provider.");
        } catch (org.omg.CosNaming.NamingContextPackage.CannotProceed e) {
            dieWithError("\nCRITICAL:Naming Service Cannot Proceed - when binding " + name + "!\n" + 
                              "         Please check with your CORBA naming service provider.");
        } catch (org.omg.CosNaming.NamingContextPackage.NotFound e) {
            dieWithError("\nCRITICAL:Naming Service Not Found - when binding " + name + "!\n" + 
                              "         Please check with your CORBA naming service provider.");
        } catch (org.omg.CosNaming.NamingContextPackage.AlreadyBound e) {
            dieWithError("\nCRITICAL:Already Bound - when binding " + name + "!\n" + 
                              "         Another component with this name is already running.");
        }
    }
    
    /**
     * Activates the POA
     * Calls the dieWithError() if any exceptions happen!
     */
    public void activatePOA() {
        try {
            getRootPOA().the_POAManager().activate();
        } catch (org.omg.PortableServer.POAManagerPackage.AdapterInactive e) {
            dieWithError("\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).
     *
     * This uses the uk.ac.ukc.iscream.util.NameFormat 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 METHODS---

    /**
     * If there are any CORBA errors this method is called with the 
     * error message.
     *
     * Currently this prints the error, on the local err stream.  Will
     * print to the logger if one is available.
     *
     * ANY CALLS TO THIS METHOD CAUSE
     * THE SYSTEM TO EXIT WITH A NON
     * ZERO CODE!
     *
     * @param message the error message to die with
     */
    private void dieWithError(String message) {
        System.err.println(message);
        if (_logger != null) {
            _logger.write(toString(), Logger.FATAL, message);
        }
        System.exit(1);
    }

//---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
     * Calls the dieWithError() if any exceptions happen!
     *
     * @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) {
                dieWithError("\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
     * Calls the dieWithError() if any exceptions happen!
     *
     * @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) {
                dieWithError("\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) {
            dieWithError("\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
     * Calls the dieWithError() if any exceptions happen!
     *
     * @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) {
            dieWithError("\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;
    }
    
//---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;
    
    /**
     * 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 = null;

//---STATIC ATTRIBUTES---
    
    /**
     * A reference to the single instance of this class
     */
    private static ReferenceManager _instance; 
}
Revision:	1.9
Committed:	Thu Jan 18 22:49:45 2001 UTC (23 years, 3 months ago) by tdb
Branch:	MAIN
CVS Tags:	HEAD
Changes since 1.8:	+2 -2 lines
State:	*FILE REMOVED*
Log Message:	These three files have been moved into the uk.ac.ukc.iscream.ComponentManager package. This was because they weren't really suited to util, which has now become a package of classes for use in the whole system, not just the server.
#	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	tdb	1.9	* @version $Id: ReferenceManager.java,v 1.8 2000/12/13 13:42:50 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	tdb	1.9	public final String REVISION = "$Revision: 1.8 $";
32	ajm	1.1
33			//---STATIC METHODS---
34
35			/**
36			* This returns a reference to the single instance of the
37			* ReferenceManager.
38			*
39	ajm	1.6	* This creates the single instance of the ReferenceManager
40			* if it does not exist by calling the private constructor.
41			*
42	ajm	1.1	* @return a reference to the ReferenceManager
43			*/
44	ajm	1.6	public static ReferenceManager getInstance() {
45	ajm	1.1	if (_instance == null) {
46	ajm	1.6	_instance = new ReferenceManager();
47	ajm	1.1	}
48			return _instance;
49			}
50
51			//---CONSTRUCTORS---
52
53			/**
54			* This is a private constructor
55			* This ensures that the system performs according to a Singleton design pattern
56	ajm	1.6	*/
57			private ReferenceManager() {
58			_orb = ORB.init(new String[] {}, null);
59			}
60	ajm	1.1
61			//---PUBLIC METHODS---
62
63			/**
64	ajm	1.2	* Obtains a CORBA reference through the naming service
65			* for the named object.
66	ajm	1.7	* Calls the dieWithError() if any exceptions happen!
67	ajm	1.2	*
68			* @param name the name of the CORBA object to resolve
69			*
70			* @return a reference to the object
71			*/
72			public org.omg.CORBA.Object getCORBARef(String name) {
73			org.omg.CORBA.Object objRef = null;
74			try {
75			objRef = getNS().resolve(getNS().to_name(name));
76			} catch (org.omg.CosNaming.NamingContextPackage.CannotProceed e) {
77	ajm	1.6	dieWithError("\nCRITICAL:Naming Service Cannot Proceed - when resolving reference to " + name + "!\n" +
78	ajm	1.5	" Please check with your CORBA naming service provider.");
79	ajm	1.2	} catch (org.omg.CosNaming.NamingContextPackage.InvalidName e) {
80	ajm	1.6	dieWithError("\nCRITICAL:Invalid Name - when resolving reference to " + name + "!\n" +
81	ajm	1.5	" Please check with your CORBA naming service provider.");
82	ajm	1.2	} catch (org.omg.CosNaming.NamingContextPackage.NotFound e) {
83	ajm	1.6	dieWithError("\nCRITICAL:Not Found - when resolving reference to " + name + "!\n" +
84	ajm	1.5	" Please check that this component is running.");
85	ajm	1.2	}
86			return objRef;
87			}
88
89			/**
90			* Binds a given servant with the given name
91			* to the naming service.
92	ajm	1.7	* Calls the dieWithError() if any exceptions happen!
93	ajm	1.2	*
94			* @param objRef a reverence to the servant object
95			* @param name the name to bind to the naming service with
96			*/
97			public void bindToOrb(org.omg.PortableServer.Servant objRef, String name) {
98			try {
99			getNS().bind(getNS().to_name(name), getRootPOA().servant_to_reference(objRef));
100			} catch (org.omg.PortableServer.POAPackage.WrongPolicy e) {
101	ajm	1.6	dieWithError("\nCRITICAL:Wrong POA Policy - when binding " + name + "!\n" +
102	ajm	1.5	" This indicates an error with your ORB.");
103	ajm	1.2	} catch (org.omg.PortableServer.POAPackage.ServantNotActive e) {
104	ajm	1.6	dieWithError("\nCRITICAL:ServantNotActive - when binding " + name + "!\n" +
105	ajm	1.5	" This indicates an error with your ORB.");
106	ajm	1.2	} catch (org.omg.CosNaming.NamingContextPackage.InvalidName e) {
107	ajm	1.6	dieWithError("\nCRITICAL:Invalid Name - when binding " + name + "!\n" +
108	ajm	1.5	" Please check with your CORBA naming service provider.");
109	ajm	1.2	} catch (org.omg.CosNaming.NamingContextPackage.CannotProceed e) {
110	ajm	1.6	dieWithError("\nCRITICAL:Naming Service Cannot Proceed - when binding " + name + "!\n" +
111	ajm	1.5	" Please check with your CORBA naming service provider.");
112	ajm	1.2	} catch (org.omg.CosNaming.NamingContextPackage.NotFound e) {
113	ajm	1.6	dieWithError("\nCRITICAL:Naming Service Not Found - when binding " + name + "!\n" +
114	ajm	1.5	" Please check with your CORBA naming service provider.");
115	ajm	1.2	} catch (org.omg.CosNaming.NamingContextPackage.AlreadyBound e) {
116	ajm	1.6	dieWithError("\nCRITICAL:Already Bound - when binding " + name + "!\n" +
117	ajm	1.5	" Another component with this name is already running.");
118	ajm	1.2	}
119			}
120
121			/**
122			* Activates the POA
123	ajm	1.7	* Calls the dieWithError() if any exceptions happen!
124	ajm	1.2	*/
125			public void activatePOA() {
126			try {
127			getRootPOA().the_POAManager().activate();
128			} catch (org.omg.PortableServer.POAManagerPackage.AdapterInactive e) {
129	ajm	1.6	dieWithError("\nCRITICAL:POA Set Inactive - when trying to activate POA!\n" +
130	ajm	1.5	" This indicates an error with your ORB.");
131	ajm	1.2	}
132			}
133
134			/**
135	ajm	1.1	* Overrides the {@link java.lang.Object#toString() Object.toString()}
136			* method to provide clean logging (every class should have this).
137			*
138	ajm	1.6	* This uses the uk.ac.ukc.iscream.util.NameFormat class
139			* to format the toString()
140			*
141	ajm	1.1	* @return the name of this class and its CVS revision
142			*/
143			public String toString() {
144	ajm	1.6	return FormatName.getName(
145	ajm	1.7	_name,
146			getClass().getName(),
147	ajm	1.6	REVISION);
148	ajm	1.1	}
149
150			//---PRIVATE METHODS---
151
152	ajm	1.6	/**
153			* If there are any CORBA errors this method is called with the
154			* error message.
155			*
156			* Currently this prints the error, on the local err stream. Will
157			* print to the logger if one is available.
158			*
159			* ANY CALLS TO THIS METHOD CAUSE
160			* THE SYSTEM TO EXIT WITH A NON
161			* ZERO CODE!
162			*
163			* @param message the error message to die with
164			*/
165			private void dieWithError(String message) {
166			System.err.println(message);
167			if (_logger != null) {
168			_logger.write(toString(), Logger.FATAL, message);
169			}
170			System.exit(1);
171			}
172
173	ajm	1.1	//---ACCESSOR/MUTATOR METHODS---
174
175			/**
176			* Returns a reference to the ORB
177			*
178			* @return the reference this class holds
179			*/
180			public ORB getORB() {
181			return _orb;
182			}
183
184			/**
185			* Returns a reference to the Root POA
186	ajm	1.7	* Calls the dieWithError() if any exceptions happen!
187	ajm	1.1	*
188			* @return the reference this class holds
189			*/
190			public POA getRootPOA() {
191			if (_rootPOA == null) {
192			org.omg.CORBA.Object objRef = null;
193			try {
194			objRef = getORB().resolve_initial_references("RootPOA");
195			} catch (org.omg.CORBA.ORBPackage.InvalidName e) {
196	ajm	1.6	dieWithError("\nCRITICAL:Unable to resolve reference to the RootPOA!\n" +
197	ajm	1.5	" This indicates an error with your ORB.");
198	ajm	1.1	}
199			_rootPOA = POAHelper.narrow(objRef);
200			}
201			return _rootPOA;
202			}
203
204			/**
205			* Returns a reference to the Naming Service
206	ajm	1.7	* Calls the dieWithError() if any exceptions happen!
207	ajm	1.1	*
208			* @return the reference this class holds
209			*/
210			public NamingContextExt getNS() {
211			if (_ns == null) {
212			org.omg.CORBA.Object objRef = null;
213			try {
214			objRef = getORB().resolve_initial_references("NameService");
215			} catch (org.omg.CORBA.ORBPackage.InvalidName e) {
216	ajm	1.6	dieWithError("\nCRITICAL:Unable to resolve reference to the Naming Service!\n" +
217	ajm	1.5	" Please check with your CORBA naming service provider.");
218	ajm	1.1	}
219			_ns = NamingContextExtHelper.narrow(objRef);
220			}
221	ajm	1.5	// check we managed to talk to the naming service
222			if (_ns == null) {
223	ajm	1.6	dieWithError("\nCRITICAL:Unable to resolve reference to the Naming Service!\n" +
224	ajm	1.5	" Please check with your CORBA naming service provider.");
225			}
226	ajm	1.1	return _ns;
227			}
228
229			/**
230			* Returns a reference to the configuration manager
231	ajm	1.7	* Calls the dieWithError() if any exceptions happen!
232	ajm	1.1	*
233			* @return the reference this class holds
234			*/
235			public ConfigurationManager getCM() {
236			if (_cm == null) {
237	ajm	1.2	_cm = ConfigurationManagerHelper.narrow(getCORBARef("iscream.ConfigurationManager"));
238	ajm	1.1	}
239	ajm	1.5	// check we managed to talk to the configuration manager
240			if (_cm == null) {
241	ajm	1.6	dieWithError("\nCRITICAL:Unable to resolve reference to the Configuration Manager!\n" +
242	ajm	1.5	" Please check with your CORBA naming service provider.");
243			}
244	ajm	1.1	return _cm;
245			}
246
247			/**
248			* Returns a reference to the logger
249	ajm	1.5	* This will throw a Error if there is an error
250	ajm	1.1	*
251			* @return the reference this class holds
252			*/
253			public Logger getLogger() {
254			if (_logger == null) {
255	ajm	1.2	_logger = LoggerHelper.narrow(getCORBARef("iscream.Logger"));
256	ajm	1.1	}
257			return _logger;
258	ajm	1.4	}
259	ajm	1.1
260			//---ATTRIBUTES---
261
262			/**
263			* The ORB
264			*/
265			private ORB _orb;
266
267			/**
268			* The Naming Service
269			*/
270			private NamingContextExt _ns;
271
272			/**
273			* The Root POA
274			*/
275			private POA _rootPOA;
276
277			/**
278			* The configuration manager
279			*/
280			private ConfigurationManager _cm;
281
282			/**
283			* The logger
284			*/
285			private Logger _logger;
286
287			/**
288	ajm	1.7	* This is the friendly identifier of the
289			* component this class is running in.
290			* eg, a Filter may be called "filter1",
291			* If this class does not have an owning
292			* component, a name from the configuration
293			* can be placed here. This name could also
294			* be changed to null for utility classes.
295	ajm	1.1	*/
296	ajm	1.7	private String _name = null;
297	ajm	1.1
298			//---STATIC ATTRIBUTES---
299
300			/**
301			* A reference to the single instance of this class
302			*/
303			private static ReferenceManager _instance;
304			}