Coverage Report

Coverage Report - org.melati.poem.util.CachedIndexFactory

Classes in this File

Line Coverage

Branch Coverage

Complexity

CachedIndexFactory

95%

21/22

100%

10/10

 /*
  * $Source$
  * $Revision$
  *
  * Copyright (C) 2000 William Chesters
  *
  * Part of Melati (http://melati.org), a framework for the rapid
  * development of clean, maintainable web applications.
  *
  * Melati is free software; Permission is granted to copy, distribute
  * and/or modify this software under the terms either:
  *
  * a) 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,
  *
  *    or
  *
  * b) any version of the Melati Software License, as published
  *    at http://melati.org
  *
  * You should have received a copy of the GNU General Public License and
  * the Melati Software License along with this program;
  * if not, write to the Free Software Foundation, Inc.,
  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA to obtain the
  * GNU General Public License and visit http://melati.org to obtain the
  * Melati Software License.
  *
  * Feel free to contact the Developers of Melati (http://melati.org),
  * if you would like to work out a different arrangement than the options
  * outlined here.  It is our intention to allow Melati to be used by as
  * wide an audience as possible.
  *
  * 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.
  *
  * Contact details for copyright holder:
  *
  *     William Chesters <williamc At paneris.org>
  *     http://paneris.org/~williamc
  *     Obrechtstraat 114, 2517VX Den Haag, The Netherlands
  */
 
 package org.melati.poem.util;
 
 import java.util.Vector;
 
 /**
  * Supply and cache objects identified by a numeric index.
  * <p>
  * Subtypes define how the object for a given index is obtained,
  * and hence the mapping of indexes to objects used in the
  * caller.
  * <p>
  * The name is a touch misleading - the objects returned are
  * not (necessarily) indexes.
  * <p>
  * <code>null</code> object references can be cached and returned.
  * <p>
  * Individual elements can be removed from the cache or all elements 
  * may be removed.
  */
 
 public abstract class CachedIndexFactory implements IndexFactory {
   
   private Vector<Object> cache = new Vector<Object>();
   private static final Object nullFromFactory = new Object();
 
   /**
    * @param index of the item, possibly a troid
    * @return the cached Object
    */
   protected abstract Object reallyGet(int index);
 
   /**
    * Get either from cache or, failing that, really get it.
    * {@inheritDoc}
    * @see org.melati.poem.util.IndexFactory#get(int)
    */
   public Object get(int index) {
     synchronized (cache) {
       if (cache.size() <= index) {
         cache.setSize(index + 1);
         Object it = reallyGet(index);
         cache.setElementAt(it == null ? nullFromFactory : it, index);
         return it;
       }
       else {
         Object it = cache.elementAt(index);
         if (it == null) {
           it = reallyGet(index);
           cache.setElementAt(it == null ? nullFromFactory : it, index);
           return it;
         }
         else if (it == nullFromFactory)
           return null;
         else
           return it;
       }
     }
   }
 
   /**
    * Invalidate an entry in the cache.
    * @param index the entry's index to invalidate
    */
   public void invalidate(int index) {
     cache.setElementAt(null, index);
   }
 
   /**
    * Invalidate whole cache.
    */
   public void invalidate() {
     cache.removeAllElements();
   }
 }
 
 
 
 

1		/*
2		* $Source$
3		* $Revision$
4		*
5		* Copyright (C) 2000 William Chesters
6		*
7		* Part of Melati (http://melati.org), a framework for the rapid
8		* development of clean, maintainable web applications.
9		*
10		* Melati is free software; Permission is granted to copy, distribute
11		* and/or modify this software under the terms either:
12		*
13		* a) the GNU General Public License as published by the Free Software
14		* Foundation; either version 2 of the License, or (at your option)
15		* any later version,
16		*
17		* or
18		*
19		* b) any version of the Melati Software License, as published
20		* at http://melati.org
21		*
22		* You should have received a copy of the GNU General Public License and
23		* the Melati Software License along with this program;
24		* if not, write to the Free Software Foundation, Inc.,
25		* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA to obtain the
26		* GNU General Public License and visit http://melati.org to obtain the
27		* Melati Software License.
28		*
29		* Feel free to contact the Developers of Melati (http://melati.org),
30		* if you would like to work out a different arrangement than the options
31		* outlined here. It is our intention to allow Melati to be used by as
32		* wide an audience as possible.
33		*
34		* This program is distributed in the hope that it will be useful,
35		* but WITHOUT ANY WARRANTY; without even the implied warranty of
36		* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
37		* GNU General Public License for more details.
38		*
39		* Contact details for copyright holder:
40		*
41		* William Chesters <williamc At paneris.org>
42		* http://paneris.org/~williamc
43		* Obrechtstraat 114, 2517VX Den Haag, The Netherlands
44		*/
45
46		package org.melati.poem.util;
47
48		import java.util.Vector;
49
50		/**
51		* Supply and cache objects identified by a numeric index.
52		* <p>
53		* Subtypes define how the object for a given index is obtained,
54		* and hence the mapping of indexes to objects used in the
55		* caller.
56		* <p>
57		* The name is a touch misleading - the objects returned are
58		* not (necessarily) indexes.
59		* <p>
60		* <code>null</code> object references can be cached and returned.
61		* <p>
62		* Individual elements can be removed from the cache or all elements
63		* may be removed.
64		*/
65
66	1263	public abstract class CachedIndexFactory implements IndexFactory {
67
68	1263	private Vector<Object> cache = new Vector<Object>();
69	1	private static final Object nullFromFactory = new Object();
70
71		/**
72		* @param index of the item, possibly a troid
73		* @return the cached Object
74		*/
75		protected abstract Object reallyGet(int index);
76
77		/**
78		* Get either from cache or, failing that, really get it.
79		* {@inheritDoc}
80		* @see org.melati.poem.util.IndexFactory#get(int)
81		*/
82		public Object get(int index) {
83	11662	synchronized (cache) {
84	11662	if (cache.size() <= index) {
85	686	cache.setSize(index + 1);
86	686	Object it = reallyGet(index);
87	686	cache.setElementAt(it == null ? nullFromFactory : it, index);
88	686	return it;
89		}
90		else {
91	10976	Object it = cache.elementAt(index);
92	10976	if (it == null) {
93	2	it = reallyGet(index);
94	2	cache.setElementAt(it == null ? nullFromFactory : it, index);
95	2	return it;
96		}
97	10974	else if (it == nullFromFactory)
98	1	return null;
99		else
100	10973	return it;
101		}
102	0	}
103		}
104
105		/**
106		* Invalidate an entry in the cache.
107		* @param index the entry's index to invalidate
108		*/
109		public void invalidate(int index) {
110	1	cache.setElementAt(null, index);
111	1	}
112
113		/**
114		* Invalidate whole cache.
115		*/
116		public void invalidate() {
117	103	cache.removeAllElements();
118	103	}
119		}
120
121
122
123