server/client/AlerterManager.java

/* 
 * i-scream central monitoring system
 * http://www.i-scream.org.uk
 * Copyright (C) 2000-2002 i-scream
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

//---PACKAGE DECLARATION---
package uk.org.iscream.cms.server.client;

//---IMPORTS---
import uk.org.iscream.cms.server.componentmanager.*;
import uk.org.iscream.cms.server.core.*;
import uk.org.iscream.cms.util.*;
import java.util.*;

/**
 * A manager for the Alerters.
 *
 * This class starts by loading all the alerters as specificed in the configuration.
 * These alerters should implement the PluginAlerter interface.
 *
 * This class is then simply a reference point for the Alerters to get hooks on
 * the various parts of the system that they require.
 *
 * @author  $Author: tdb $
 * @version $Id: AlerterManager.java,v 1.11 2002/05/21 16:47:16 tdb Exp $
 */
public class AlerterManager extends Thread {

//---FINAL ATTRIBUTES---

    /**
     * The current CVS revision of this class
     */
    public static final String REVISION = "$Revision: 1.11 $";
    
//---STATIC METHODS---
    
    /**
     * Return a reference to the single class.
     * Construct it if it does not already exist, otherwise just return the reference.
     */
    public synchronized static AlerterManager getInstance() {
        if (_instance == null){
            _instance = new AlerterManager();
        }
        return _instance;
    }

//---CONSTRUCTORS---
    
    /**
     * Constructs a new AlerterManager.
     * This initialises all the queues and loads
     * all the Alerters that have been specified in the configuration
     */
    private AlerterManager() {
        // set our name
        setName("client.AlerterManager");
        
        _logger.write(toString(), Logger.SYSINIT, "Initialising");
        _logger.write(toString(), Logger.SYSMSG, "Creating alerter pipeline for plugin alerters ...");
        
        // get the config proxy
        ConfigurationProxy cp = ConfigurationProxy.getInstance();
        
        // get the configuration for this plug-in setup
        String pluginsPackage, pluginsList;
        try {
            pluginsPackage = cp.getProperty(_name, "Alerter.PluginsPackage");
            pluginsList = cp.getProperty(_name, "Alerter.Plugins");
        } catch(PropertyNotFoundException e) {
            _logger.write(toString(), Logger.WARNING, "Unable to get required configuration, Alerter's will not be activated: "+e);
            // setting these will ensure we don't build a pipeline
            pluginsPackage = "";
            pluginsList = "";
        }
        
        StringTokenizer st = new StringTokenizer(pluginsList, ";");
        
        while(st.hasMoreTokens()) {
            String className = pluginsPackage + "." + st.nextToken() + _suffix;
            _logger.write(toString(), Logger.DEBUG, "Attempting to create plugin: "+className);
            
            // Create an instance of the specified PluginAlerter to include
            // within the alerterPipe.  Add it to the alerterPipeline
            try {
                PluginAlerter pa = (PluginAlerter)ClassLoader.getSystemClassLoader().loadClass(className).newInstance();
                _alerterPipeline.add(pa);
                _logger.write(toString(), Logger.DEBUG, "Added alerter: "+className+" ("+pa.getDescription()+")");
            }
            catch (InstantiationException e){
                _logger.write(toString(), Logger.ERROR, "Failed to instantiate "+className+" to the plugin alerter pipeline.");
                _logger.write(toString(), Logger.ERROR, e.getMessage());
            }
            catch (Exception e){
                _logger.write(toString(), Logger.ERROR, "Failed to add "+className+" to the plugin alerter pipeline.");
                _logger.write(toString(), Logger.ERROR, e.toString());
            }
        }
        _logger.write(toString(), Logger.SYSMSG, "The alerter pipeline has been set up with "+_alerterPipeline.size()+" plugin alerters.");
    }

//---PUBLIC METHODS---

    /**
     * Overrides the {@link java.lang.Object#toString() Object.toString()}
     * method to provide clean logging (every class should have this).
     *
     * This uses the uk.org.iscream.cms.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 METHODS---

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

    /**
     * Allows alerters to obtain a reference
     * to the alerting queue so that they can 
     * process any alerts
     *
     * @return a reference to the alert queue
     */
    public Queue getQueue() {
        return ClientMain._alerterQueue;
    }

//---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 = ClientMain.NAME;

    /**
     * This holds a reference to the
     * system logger that is being used.
     */
    private Logger _logger = ReferenceManager.getInstance().getLogger();
    
    /**
     * A reference to the reference manager in use
     */
    private ReferenceManager _refman = ReferenceManager.getInstance();
    
    /**
     * file name suffix for plugin alerter classes:
     */
    private final String _suffix = "__Alerter";
    
    /**
     * LinkedList for holding the PluginAlerter objects (the pipeline).
     */
    private LinkedList _alerterPipeline = new LinkedList();

//---STATIC ATTRIBUTES---

    /**
     * A reference to the single instance of this class
     */
    private static AlerterManager _instance;

}
Revision:	1.12
Committed:	Wed Feb 5 16:43:44 2003 UTC (21 years, 3 months ago) by tdb
Branch:	MAIN
Changes since 1.11:	+4 -4 lines
Log Message:	Changed the server to use the external util package. Quite a minor change, but does affect a lot of files.
#	Content
1	/*
2	* i-scream central monitoring system
3	* http://www.i-scream.org.uk
4	* Copyright (C) 2000-2002 i-scream
5	*
6	* This program is free software; you can redistribute it and/or
7	* modify it under the terms of the GNU General Public License
8	* as published by the Free Software Foundation; either version 2
9	* of the License, or (at your option) any later version.
10	*
11	* This program is distributed in the hope that it will be useful,
12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14	* GNU General Public License for more details.
15	*
16	* You should have received a copy of the GNU General Public License
17	* along with this program; if not, write to the Free Software
18	* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19	*/
20
21	//---PACKAGE DECLARATION---
22	package uk.org.iscream.cms.server.client;
23
24	//---IMPORTS---
25	import uk.org.iscream.cms.server.componentmanager.*;
26	import uk.org.iscream.cms.server.core.*;
27	import uk.org.iscream.cms.util.*;
28	import java.util.*;
29
30	/**
31	* A manager for the Alerters.
32	*
33	* This class starts by loading all the alerters as specificed in the configuration.
34	* These alerters should implement the PluginAlerter interface.
35	*
36	* This class is then simply a reference point for the Alerters to get hooks on
37	* the various parts of the system that they require.
38	*
39	* @author $Author: tdb $
40	* @version $Id: AlerterManager.java,v 1.11 2002/05/21 16:47:16 tdb Exp $
41	*/
42	public class AlerterManager extends Thread {
43
44	//---FINAL ATTRIBUTES---
45
46	/**
47	* The current CVS revision of this class
48	*/
49	public static final String REVISION = "$Revision: 1.11 $";
50
51	//---STATIC METHODS---
52
53	/**
54	* Return a reference to the single class.
55	* Construct it if it does not already exist, otherwise just return the reference.
56	*/
57	public synchronized static AlerterManager getInstance() {
58	if (_instance == null){
59	_instance = new AlerterManager();
60	}
61	return _instance;
62	}
63
64	//---CONSTRUCTORS---
65
66	/**
67	* Constructs a new AlerterManager.
68	* This initialises all the queues and loads
69	* all the Alerters that have been specified in the configuration
70	*/
71	private AlerterManager() {
72	// set our name
73	setName("client.AlerterManager");
74
75	_logger.write(toString(), Logger.SYSINIT, "Initialising");
76	_logger.write(toString(), Logger.SYSMSG, "Creating alerter pipeline for plugin alerters ...");
77
78	// get the config proxy
79	ConfigurationProxy cp = ConfigurationProxy.getInstance();
80
81	// get the configuration for this plug-in setup
82	String pluginsPackage, pluginsList;
83	try {
84	pluginsPackage = cp.getProperty(_name, "Alerter.PluginsPackage");
85	pluginsList = cp.getProperty(_name, "Alerter.Plugins");
86	} catch(PropertyNotFoundException e) {
87	_logger.write(toString(), Logger.WARNING, "Unable to get required configuration, Alerter's will not be activated: "+e);
88	// setting these will ensure we don't build a pipeline
89	pluginsPackage = "";
90	pluginsList = "";
91	}
92
93	StringTokenizer st = new StringTokenizer(pluginsList, ";");
94
95	while(st.hasMoreTokens()) {
96	String className = pluginsPackage + "." + st.nextToken() + _suffix;
97	_logger.write(toString(), Logger.DEBUG, "Attempting to create plugin: "+className);
98
99	// Create an instance of the specified PluginAlerter to include
100	// within the alerterPipe. Add it to the alerterPipeline
101	try {
102	PluginAlerter pa = (PluginAlerter)ClassLoader.getSystemClassLoader().loadClass(className).newInstance();
103	_alerterPipeline.add(pa);
104	_logger.write(toString(), Logger.DEBUG, "Added alerter: "+className+" ("+pa.getDescription()+")");
105	}
106	catch (InstantiationException e){
107	_logger.write(toString(), Logger.ERROR, "Failed to instantiate "+className+" to the plugin alerter pipeline.");
108	_logger.write(toString(), Logger.ERROR, e.getMessage());
109	}
110	catch (Exception e){
111	_logger.write(toString(), Logger.ERROR, "Failed to add "+className+" to the plugin alerter pipeline.");
112	_logger.write(toString(), Logger.ERROR, e.toString());
113	}
114	}
115	_logger.write(toString(), Logger.SYSMSG, "The alerter pipeline has been set up with "+_alerterPipeline.size()+" plugin alerters.");
116	}
117
118	//---PUBLIC METHODS---
119
120	/**
121	* Overrides the {@link java.lang.Object#toString() Object.toString()}
122	* method to provide clean logging (every class should have this).
123	*
124	* This uses the uk.org.iscream.cms.util.FormatName class
125	* to format the toString()
126	*
127	* @return the name of this class and its CVS revision
128	*/
129	public String toString() {
130	return FormatName.getName(
131	_name,
132	getClass().getName(),
133	REVISION);
134	}
135
136	//---PRIVATE METHODS---
137
138	//---ACCESSOR/MUTATOR METHODS---
139
140	/**
141	* Allows alerters to obtain a reference
142	* to the alerting queue so that they can
143	* process any alerts
144	*
145	* @return a reference to the alert queue
146	*/
147	public Queue getQueue() {
148	return ClientMain._alerterQueue;
149	}
150
151	//---ATTRIBUTES---
152
153	/**
154	* This is the friendly identifier of the
155	* component this class is running in.
156	* eg, a Filter may be called "filter1",
157	* If this class does not have an owning
158	* component, a name from the configuration
159	* can be placed here. This name could also
160	* be changed to null for utility classes.
161	*/
162	private String _name = ClientMain.NAME;
163
164	/**
165	* This holds a reference to the
166	* system logger that is being used.
167	*/
168	private Logger _logger = ReferenceManager.getInstance().getLogger();
169
170	/**
171	* A reference to the reference manager in use
172	*/
173	private ReferenceManager _refman = ReferenceManager.getInstance();
174
175	/**
176	* file name suffix for plugin alerter classes:
177	*/
178	private final String _suffix = "__Alerter";
179
180	/**
181	* LinkedList for holding the PluginAlerter objects (the pipeline).
182	*/
183	private LinkedList _alerterPipeline = new LinkedList();
184
185	//---STATIC ATTRIBUTES---
186
187	/**
188	* A reference to the single instance of this class
189	*/
190	private static AlerterManager _instance;
191
192	}