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1 package net.simya.ldap.servlet;
2
3 import javax.servlet.http.*;
4 import javax.servlet.*;
5 import java.util.Hashtable  ;
6 import java.util.Random ;
7 import java.util.Enumeration ;
8
9 public
10 class LdapGlobalCache
11 extends HttpServlet
12 implements Runnable
13 {
14 private static Hashtable objects = new Hashtable ();
15
16 private boolean isActive = true;
17
18 public void init()
19 {
20 new Thread ( this ).start();
21 }
22
23 public void doGet( HttpServletRequest req, HttpServletResponse res )
24 {
25 String id = req.getParameter( "id" );
26 if ( id == null )
27 return;
28 if ( id.equals( "MANAGER" ) )
29 {
30 try
31 {
32 java.io.PrintWriter out = res.getWriter();
33 out.println( "<html><head><title>LDAP Taglib Info</title></head>" );
34 out.println( "<body><b>Total object(s) waiting in cache buffer : </b>" );
35 out.println( objects.size() );
36 out.println( "</body></html>" );
37 } catch ( java.io.IOException ex )
38 {
39 }
40 return;
41 }
42
43 CacheObject cached = (CacheObject) objects.get( id );
44
45 try
46 {
47 ServletOutputStream out = res.getOutputStream();
48 res.setContentType( cached.mimeType );
49 out.write( (byte[]) cached.object );
50 } catch (java.io.IOException ex)
51 {
52 }
53 finally
54 {
55 synchronized( objects )
56 {
57 objects.remove( id );
58 }
59 }
60 }
61
62 public static String addCache( Object object, String mimeType )
63 {
64 String id = null;
65 do
66 {
67 id = generateRndId();
68 }
69 while( objects.containsKey( id ) );
70 synchronized( objects )
71 {
72 objects.put( id, new CacheObject(object, mimeType) );
73 }
74 return id;
75 }
76
77 public static String generateRndId()
78 {
79 byte[] b = new byte[ 20 ];
80 char[] c = new char[ 20 ];
81 Random r = new Random ();
82 r.nextBytes( b );
83 for ( int i = 0; i < b.length; i++ )
84 {
85 c[ i ] = (char) ((b[ i ] & 0xff) % 123);
86 if ( c[ i ] < 65 )
87 c[ i ] = (char) (c[ i ] % 10 + 48) ;
88 if ( c[ i ] < 97 && c[ i ] > 90 )
89 c[ i ] = 95;
90 if ( c[ 0 ] < 65 )
91 c[ 0 ] += 18;
92 }
93 return new String ( c );
94 }
95
96 public void destroy()
97 {
98 isActive = false;
99 }
100
101 public void run()
102 {
103 long SEEK_PERIOD = 30000;
104
105 while ( isActive )
106 {
107 try
108 {
109 Thread.sleep( SEEK_PERIOD );
110 } catch ( InterruptedException ex ) {}
111 synchronized( objects )
112 {
113 for ( Enumeration e = objects.keys(); e.hasMoreElements(); )
114 {
115 Object key = e.nextElement();
116 CacheObject o = (CacheObject) objects.get( key );
117 if ( o.isExpired() )
118 objects.remove( key );
119 }
120 }
121 }
122 }
123
124 }
125
126 class CacheObject
127 {
128 private static final long DELAY = 180000; Object object;
130 String mimeType;
131 long timeStamp = System.currentTimeMillis();
132
133 CacheObject( Object _object, String _mimeType )
134 {
135 this.object = _object;
136 this.mimeType = _mimeType;
137 }
138
139 boolean isExpired()
140 {
141 return (System.currentTimeMillis() - timeStamp) > DELAY;
142 }
143 }
144 |
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