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root/i-scream/projects/cms/source/server/uk/org/iscream/cms/server/filter/PluginFilterManager.java

Comparing projects/cms/source/server/uk/org/iscream/cms/server/filter/PluginFilterManager.java (file contents):
Revision 1.1 by tdb, Wed Dec 6 22:58:30 2000 UTC vs.
Revision 1.12 by tdb, Tue May 21 16:47:17 2002 UTC

#	Line 1 | Line 1
1	<	//---PACKAGE DECLARATION---
2	<	package uk.ac.ukc.iscream.filter;
3	<
4	<	//---IMPORTS---
5	<	import java.io.*;
6	<	import java.util.*;
7	<
8	<	import uk.ac.ukc.iscream.util.*;
9	<	import uk.ac.ukc.iscream.core.*;
10	<
11	<	/**
12	<	* the plugin filter manager
13	<	* This is a singleton class.
14	<	*
15	<	* @author  $Author$
16	<	* @version $Id$
17	<	*/
18	<	class PluginFilterManager {
19	<
20	<	//---FINAL ATTRIBUTES---
21	<
22	<	/**
23	<	* The current CVS revision of this class
24	<	*/
25	<	public final String REVISION = "$Revision$";
26	<
27	<	//---STATIC METHODS---
28	<
29	<	// Return a reference to the single class.
30	<	// Construct it if it does not already exist, otherwise just return the reference.
31	<	public static PluginFilterManager getInstance() throws NotInitialisedException {
32	<	if (_instance == null){
33	<	return new PluginFilterManager();
34	<	}
35	<	return _instance;
36	<	}
37	<
38	<	//---CONSTRUCTORS---
39	<
40	<	// Private Constructor - this part creates the filter pipeline
41	<	// This is a singleton class, btw.
42	<	private PluginFilterManager(){
43	<
44	<	_logger.write(toString(), Logger.SYSINIT, "Initialising");
45	<	_logger.write(toString(), Logger.SYSMSG, "Creating filter pipeline for plugin filters ...");
46	<
47	<	// Get our config
48	<	ReferenceManager refman = ReferenceManager.getInstance();
49	<	Configuration config = refman.getCM().getConfiguration(refman.getName());
50	<	String pluginsPackage = config.getProperty("Filter.PluginsPackage");
51	<	String pluginsList = config.getProperty("Filter.Plugins");
52	<
53	<	StringTokenizer st = new StringTokenizer(pluginsList, ";");
54	<
55	<	while(st.hasMoreTokens()) {
56	<	String className = pluginsPackage + "." + st.nextToken() + _suffix;
57	<	_logger.write(toString(), Logger.DEBUG, "Attempting to create plugin: "+className);
58	<
59	<	// Create an instance of the specified PluginFilter to include
60	<	// within the filterPipe.  Add it to the filterPipeline
61	<	try {
62	<	PluginFilter pf = (PluginFilter)ClassLoader.getSystemClassLoader().loadClass(className).newInstance();
63	<	_filterPipeline.add(pf);
64	<	_logger.write(toString(), Logger.DEBUG, "Added filter: "+className+" ("+pf.getDescription()+")");
65	<	}
66	<	catch (InstantiationException e){
67	<	_logger.write(toString(), Logger.ERROR, "Failed to instantiate "+className+" to the plugin filter pipeline.");
68	<	_logger.write(toString(), Logger.ERROR, e.getMessage());
69	<	}
70	<	catch (Exception e){
71	<	_logger.write(toString(), Logger.ERROR, "Failed to add "+className+" to the plugin filter pipeline.");
72	<	_logger.write(toString(), Logger.ERROR, e.toString());
73	<	}
74	<	}
75	<	_logger.write(toString(), Logger.SYSMSG, "The filter pipeline has been set up with "+_filterPipeline.size()+" plugin filters.");
76	<
77	<	}
78	<
79	<	//---PUBLIC METHODS---
80	<
81	<	// apply all of the filters in the pipeline to the packet.
82	<	// return true if they all accept the packet.
83	<	// return false if any single filter rejects the packet.
84	<	// return true if there are no filters inthe pipeline.
85	<	public boolean runFilters(XMLPacket packet){
86	<
87	<	// for each filter in the pipeline...
88	<	ListIterator pluginFilters = _filterPipeline.listIterator(0);
89	<	while (pluginFilters.hasNext()){
90	<	PluginFilter filter = (PluginFilter)pluginFilters.next();
91	<	if (!filter.runFilter(packet)){
92	<	return false;
93	<	}
94	<	}
95	<
96	<	return true;
97	<	}
98	<
99	<	/**
100	<	* Overrides the {@link java.lang.Object#toString() Object.toString()}
101	<	* method to provide clean logging (every class should have this).
102	<	*
103	<	* @return the name of this class and its CVS revision
104	<	*/
105	<	public String toString() {
106	<	return this.getClass().getName() + "(" + REVISION.substring(11, REVISION.length() - 2) + ")";
107	<	}
108	<
109	<	//---PRIVATE METHODS---
110	<
111	<	//---ACCESSOR/MUTATOR METHODS---
112	<
113	<	//---ATTRIBUTES---
114	<
115	<	// file name suffix for plugin filter classes:
116	<	private final String _suffix = "__Plugin";
117	<
118	<	// LinkedList for holding the PluginFilter objects (the pipeline).
119	<	private LinkedList _filterPipeline = new LinkedList();
120	<
121	<	// A reference to the single instance of this class
122	<	private static PluginFilterManager _instance;
123	<
124	<	/**
125	<	* Reference to a Logger
126	<	*/
127	<	private Logger _logger = ReferenceManager.getInstance().getLogger();
128	<
129	<	//---STATIC ATTRIBUTES---
130	<
131	<	}
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.filter;
23	>
24	>	//---IMPORTS---
25	>	import java.io.*;
26	>	import java.util.*;
27	>
28	>	import uk.org.iscream.cms.server.util.*;
29	>	import uk.org.iscream.cms.server.componentmanager.*;
30	>	import uk.org.iscream.cms.server.core.*;
31	>
32	>	/**
33	>	* This class setups up and manages Plugins in a Filter. A list
34	>	* of plugins to use is specified in the configuration, and these
35	>	* are all loaded upon first use of this class.
36	>	* This is a singleton class.
37	>	*
38	>	* @author  $Author$
39	>	* @version $Id$
40	>	*/
41	>	class PluginFilterManager {
42	>
43	>	//---FINAL ATTRIBUTES---
44	>
45	>	/**
46	>	* The current CVS revision of this class
47	>	*/
48	>	public final String REVISION = "$Revision$";
49	>
50	>	//---STATIC METHODS---
51	>
52	>	/**
53	>	* Return a reference to the single class.
54	>	* Construct it if it does not already exist, otherwise just return the reference.
55	>	*/
56	>	public static PluginFilterManager getInstance() {
57	>	if (_instance == null){
58	>	_instance = new PluginFilterManager();
59	>	}
60	>	return _instance;
61	>	}
62	>
63	>	//---CONSTRUCTORS---
64	>
65	>	/**
66	>	* Private Constructor - this part creates the filter pipeline
67	>	* This is a singleton class, btw.
68	>	*/
69	>	private PluginFilterManager(){
70	>
71	>	_logger.write(toString(), Logger.SYSINIT, "Initialising");
72	>	_logger.write(toString(), Logger.SYSMSG, "Creating filter pipeline for plugin filters ...");
73	>
74	>	String pluginsPackage, pluginsList;
75	>
76	>	try {
77	>	// get the configuration for this plug-in setup
78	>	ConfigurationProxy cp = ConfigurationProxy.getInstance();
79	>	pluginsPackage = cp.getProperty("Filter." + FilterMain.NAME, "Filter.PluginsPackage");
80	>	pluginsList = cp.getProperty("Filter." + FilterMain.NAME, "Filter.Plugins");
81	>	} catch (PropertyNotFoundException e) {
82	>	_logger.write(toString(), Logger.WARNING, "Unable to locate property: "+e);
83	>	// setting this to "" will avoid building a plugin list,
84	>	// which is what we want when a property doesn't exist
85	>	pluginsList = "";
86	>	// and set this to "", because the compiler is a git
87	>	pluginsPackage = "";
88	>	}
89	>
90	>	StringTokenizer st = new StringTokenizer(pluginsList, ";");
91	>
92	>	while(st.hasMoreTokens()) {
93	>	String className = pluginsPackage + "." + st.nextToken() + _suffix;
94	>	_logger.write(toString(), Logger.DEBUG, "Attempting to create plugin: "+className);
95	>
96	>	// Create an instance of the specified PluginFilter to include
97	>	// within the filterPipe.  Add it to the filterPipeline
98	>	try {
99	>	PluginFilter pf = (PluginFilter)ClassLoader.getSystemClassLoader().loadClass(className).newInstance();
100	>	_filterPipeline.add(pf);
101	>	_logger.write(toString(), Logger.DEBUG, "Added filter: "+className+" ("+pf.getDescription()+")");
102	>	}
103	>	catch (InstantiationException e){
104	>	_logger.write(toString(), Logger.ERROR, "Failed to instantiate "+className+" to the plugin filter pipeline.");
105	>	_logger.write(toString(), Logger.ERROR, e.getMessage());
106	>	}
107	>	catch (Exception e){
108	>	_logger.write(toString(), Logger.ERROR, "Failed to add "+className+" to the plugin filter pipeline.");
109	>	_logger.write(toString(), Logger.ERROR, e.toString());
110	>	}
111	>	}
112	>	_logger.write(toString(), Logger.SYSMSG, "The filter pipeline has been set up with "+_filterPipeline.size()+" plugin filters.");
113	>
114	>	}
115	>
116	>	//---PUBLIC METHODS---
117	>
118	>	/**
119	>	* apply all of the filters in the pipeline to the packet.
120	>	* return true if they all accept the packet.
121	>	* return false if any single filter rejects the packet.
122	>	* return true if there are no filters inthe pipeline.
123	>	*
124	>	* @param packet an XMLPacket to be tested
125	>	* @return whether the packet can be passed on
126	>	*/
127	>	public boolean runFilters(XMLPacket packet){
128	>
129	>	// for each filter in the pipeline...
130	>	ListIterator pluginFilters = _filterPipeline.listIterator(0);
131	>	while (pluginFilters.hasNext()){
132	>	PluginFilter filter = (PluginFilter)pluginFilters.next();
133	>	if (!filter.runFilter(packet)){
134	>	return false;
135	>	}
136	>	}
137	>
138	>	return true;
139	>	}
140	>
141	>	/**
142	>	* Overrides the {@link java.lang.Object#toString() Object.toString()}
143	>	* method to provide clean logging (every class should have this).
144	>	*
145	>	* This uses the uk.org.iscream.cms.server.util.NameFormat class
146	>	* to format the toString()
147	>	*
148	>	* @return the name of this class and its CVS revision
149	>	*/
150	>	public String toString() {
151	>	return FormatName.getName(
152	>	_name,
153	>	getClass().getName(),
154	>	REVISION);
155	>	}
156	>
157	>	//---PRIVATE METHODS---
158	>
159	>	//---ACCESSOR/MUTATOR METHODS---
160	>
161	>	//---ATTRIBUTES---
162	>
163	>	/**
164	>	* file name suffix for plugin filter classes:
165	>	*/
166	>	private final String _suffix = "__Plugin";
167	>
168	>	/**
169	>	* LinkedList for holding the PluginFilter objects (the pipeline).
170	>	*/
171	>	private LinkedList _filterPipeline = new LinkedList();
172	>
173	>	/**
174	>	* A reference to the single instance of this class
175	>	*/
176	>	private static PluginFilterManager _instance;
177	>
178	>	/**
179	>	* This is the friendly identifier of the
180	>	* component this class is running in.
181	>	* eg, a Filter may be called "filter1",
182	>	* If this class does not have an owning
183	>	* component,  a name from the configuration
184	>	* can be placed here.  This name could also
185	>	* be changed to null for utility classes.
186	>	*/
187	>	private String _name = FilterMain.NAME;
188	>
189	>	/**
190	>	* This holds a reference to the
191	>	* system logger that is being used.
192	>	*/
193	>	private Logger _logger = ReferenceManager.getInstance().getLogger();
194	>
195	>	/**
196	>	* A reference to the reference manager in use
197	>	*/
198	>	private ReferenceManager _refman = ReferenceManager.getInstance();
199	>
200	>	//---STATIC ATTRIBUTES---
201	>
202	>	}

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