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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 1.3 by ajm, Wed Dec 13 13:36:46 2000 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	>	//---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	>	/**
30	>	* Return a reference to the single class.
31	>	* Construct it if it does not already exist, otherwise just return the reference.
32	>	*/
33	>	public static PluginFilterManager getInstance() {
34	>	if (_instance == null){
35	>	_instance = new PluginFilterManager();
36	>	}
37	>	return _instance;
38	>	}
39	>
40	>	//---CONSTRUCTORS---
41	>
42	>	/**
43	>	* Private Constructor - this part creates the filter pipeline
44	>	* This is a singleton class, btw.
45	>	*/
46	>	private PluginFilterManager(){
47	>
48	>	_logger.write(toString(), Logger.SYSINIT, "Initialising");
49	>	_logger.write(toString(), Logger.SYSMSG, "Creating filter pipeline for plugin filters ...");
50	>
51	>	Configuration config = _refman.getCM().getConfiguration(FilterMain.NAME);
52	>	String pluginsPackage = config.getProperty("Filter.PluginsPackage");
53	>	String pluginsList = config.getProperty("Filter.Plugins");
54	>
55	>	StringTokenizer st = new StringTokenizer(pluginsList, ";");
56	>
57	>	while(st.hasMoreTokens()) {
58	>	String className = pluginsPackage + "." + st.nextToken() + _suffix;
59	>	_logger.write(toString(), Logger.DEBUG, "Attempting to create plugin: "+className);
60	>
61	>	// Create an instance of the specified PluginFilter to include
62	>	// within the filterPipe.  Add it to the filterPipeline
63	>	try {
64	>	PluginFilter pf = (PluginFilter)ClassLoader.getSystemClassLoader().loadClass(className).newInstance();
65	>	_filterPipeline.add(pf);
66	>	_logger.write(toString(), Logger.DEBUG, "Added filter: "+className+" ("+pf.getDescription()+")");
67	>	}
68	>	catch (InstantiationException e){
69	>	_logger.write(toString(), Logger.ERROR, "Failed to instantiate "+className+" to the plugin filter pipeline.");
70	>	_logger.write(toString(), Logger.ERROR, e.getMessage());
71	>	}
72	>	catch (Exception e){
73	>	_logger.write(toString(), Logger.ERROR, "Failed to add "+className+" to the plugin filter pipeline.");
74	>	_logger.write(toString(), Logger.ERROR, e.toString());
75	>	}
76	>	}
77	>	_logger.write(toString(), Logger.SYSMSG, "The filter pipeline has been set up with "+_filterPipeline.size()+" plugin filters.");
78	>
79	>	}
80	>
81	>	//---PUBLIC METHODS---
82	>
83	>	/**
84	>	* apply all of the filters in the pipeline to the packet.
85	>	* return true if they all accept the packet.
86	>	* return false if any single filter rejects the packet.
87	>	* return true if there are no filters inthe pipeline.
88	>	*/
89	>	public boolean runFilters(XMLPacket packet){
90	>
91	>	// for each filter in the pipeline...
92	>	ListIterator pluginFilters = _filterPipeline.listIterator(0);
93	>	while (pluginFilters.hasNext()){
94	>	PluginFilter filter = (PluginFilter)pluginFilters.next();
95	>	if (!filter.runFilter(packet)){
96	>	return false;
97	>	}
98	>	}
99	>
100	>	return true;
101	>	}
102	>
103	>	/**
104	>	* Overrides the {@link java.lang.Object#toString() Object.toString()}
105	>	* method to provide clean logging (every class should have this).
106	>	*
107	>	* This uses the uk.ac.ukc.iscream.util.NameFormat class
108	>	* to format the toString()
109	>	*
110	>	* @return the name of this class and its CVS revision
111	>	*/
112	>	public String toString() {
113	>	return FormatName.getName(
114	>	_name,
115	>	getClass().getName(),
116	>	REVISION);
117	>	}
118	>
119	>	//---PRIVATE METHODS---
120	>
121	>	//---ACCESSOR/MUTATOR METHODS---
122	>
123	>	//---ATTRIBUTES---
124	>
125	>	/**
126	>	* file name suffix for plugin filter classes:
127	>	*/
128	>	private final String _suffix = "__Plugin";
129	>
130	>	/**
131	>	* LinkedList for holding the PluginFilter objects (the pipeline).
132	>	*/
133	>	private LinkedList _filterPipeline = new LinkedList();
134	>
135	>	/**
136	>	* A reference to the single instance of this class
137	>	*/
138	>	private static PluginFilterManager _instance;
139	>
140	>	/**
141	>	* This is the friendly identifier of the
142	>	* component this class is running in.
143	>	* eg, a Filter may be called "filter1",
144	>	* If this class does not have an owning
145	>	* component,  a name from the configuration
146	>	* can be placed here.  This name could also
147	>	* be changed to null for utility classes.
148	>	*/
149	>	private String _name = FilterMain.NAME;
150	>
151	>	/**
152	>	* This holds a reference to the
153	>	* system logger that is being used.
154	>	*/
155	>	private Logger _logger = ReferenceManager.getInstance().getLogger();
156	>
157	>	/**
158	>	* A reference to the reference manager in use
159	>	*/
160	>	private ReferenceManager _refman = ReferenceManager.getInstance();
161	>
162	>	//---STATIC ATTRIBUTES---
163	>
164	>	}

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