OPeNDAP Hyrax Back End Server (BES)  Updated for version 3.8.3
BESCache.h
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1 // BESCache.h
2 
3 // This file is part of bes, A C++ back-end server implementation framework
4 // for the OPeNDAP Data Access Protocol.
5 
6 // Copyright (c) 2004-2009 University Corporation for Atmospheric Research
7 // Author: Patrick West <pwest@ucar.edu> and Jose Garcia <jgarcia@ucar.edu>
8 //
9 // This library is free software; you can redistribute it and/or
10 // modify it under the terms of the GNU Lesser General Public
11 // License as published by the Free Software Foundation; either
12 // version 2.1 of the License, or (at your option) any later version.
13 //
14 // This library is distributed in the hope that it will be useful,
15 // but WITHOUT ANY WARRANTY; without even the implied warranty of
16 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 // Lesser General Public License for more details.
18 //
19 // You should have received a copy of the GNU Lesser General Public
20 // License along with this library; if not, write to the Free Software
21 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22 //
23 // You can contact University Corporation for Atmospheric Research at
24 // 3080 Center Green Drive, Boulder, CO 80301
25 
26 // (c) COPYRIGHT University Corporation for Atmospheric Research 2004-2005
27 // Please read the full copyright statement in the file COPYRIGHT_UCAR.
28 //
29 // Authors:
30 // pwest Patrick West <pwest@ucar.edu>
31 // jgarcia Jose Garcia <jgarcia@ucar.edu>
32 
33 #ifndef BESCache_h_
34 #define BESCache_h_ 1
35 
36 #include <string>
37 
38 using std::string ;
39 
40 #include "BESObj.h"
41 
42 class BESKeys ;
43 
44 #define MAX_LOCK_RETRY_MS 5000 // in microseconds
45 #define MAX_LOCK_TRIES 16
46 
57 class BESCache : public BESObj
58 {
59 private:
60  string _cache_dir ;
61  string _prefix ;
62  unsigned int _cache_size ;
63  int _lock_fd ;
64 
65  void check_ctor_params();
66  BESCache() {}
67 public:
68  BESCache( const string &cache_dir,
69  const string &prefix,
70  unsigned int size ) ;
71  BESCache( BESKeys &keys,
72  const string &cache_dir_key,
73  const string &prefix_key,
74  const string &size_key ) ;
75  virtual ~BESCache() {}
76 
77  virtual bool lock( unsigned int retry_ms,
78  unsigned int num_tries ) ;
79  virtual bool unlock() ;
80 
81  virtual bool is_cached( const string &src, string &target ) ;
82  virtual void purge( ) ;
83 
84  string cache_dir( ) { return _cache_dir ; }
85  string prefix( ) { return _prefix ; }
86  unsigned int cache_size( ) { return _cache_size ; }
87 
88  virtual void dump( ostream &strm ) const ;
89 };
90 
91 #endif // BESCache_h_
92 
virtual bool lock(unsigned int retry_ms, unsigned int num_tries)
lock the cache using a file lock
Definition: BESCache.cc:187
virtual void purge()
Check to see if the cache size exceeds the size specified in the constructor and purge older files un...
Definition: BESCache.cc:314
Implementation of a caching mechanism.
Definition: BESCache.h:57
unsigned int cache_size()
Definition: BESCache.h:86
virtual void dump(ostream &strm) const
dumps information about this object
Definition: BESCache.cc:457
Base object for bes objects.
Definition: BESObj.h:52
mapping of key/value pairs defining different behaviors of an application.
Definition: BESKeys.h:84
string cache_dir()
Definition: BESCache.h:84
virtual bool unlock()
unlock the cache
Definition: BESCache.cc:239
virtual ~BESCache()
Definition: BESCache.h:75
virtual bool is_cached(const string &src, string &target)
Determine if the file specified by src is cached.
Definition: BESCache.cc:270
string prefix()
Definition: BESCache.h:85