1 /***
2 * Redistribution and use in source and binary forms, with or without
3 * modification, are permitted provided that the following conditions are
4 * met :
5 *
6 * . Redistributions of source code must retain the above copyright
7 * notice, this list of conditions and the following disclaimer.
8 *
9 * . Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * . The name of the author may not be used to endorse or promote products
14 * derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
18 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
19 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
20 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
21 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
22 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
24 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
25 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 *
28 * $Id: RecordBufferManager.java 372 2005-12-28 04:22:43Z mat007 $
29 */
30
31 package palmed.buffer;
32
33 import java.io.IOException;
34 import java.io.InputStream;
35 import java.io.OutputStream;
36 import java.util.Enumeration;
37 import java.util.Stack;
38 import palmed.file.IFile;
39 import palmed.io.ISerializable;
40
41 /***
42 * This class provides multi-buffer support using records.
43 *
44 * @author Mathieu Champlon
45 * @version $Revision: 372 $ $Date: 2005-12-28 13:22:43 +0900 (mer., 28 déc. 2005) $
46 */
47 public final class RecordBufferManager implements IBufferManager, ISerializable
48 {
49 /***
50 * The record buffer stack.
51 */
52 private final Stack buffers_;
53 /***
54 * The buffer factory.
55 */
56 private final IBufferFactory factory_;
57
58 /***
59 * Create a buffer manager.
60 *
61 * @param factory the buffer factory
62 */
63 public RecordBufferManager( final IBufferFactory factory )
64 {
65 if( factory == null )
66 throw new IllegalArgumentException( "parameter 'factory' is null" );
67 buffers_ = new Stack();
68 factory_ = factory;
69 }
70
71 private IRecordBuffer getBuffer()
72 {
73 if( buffers_.empty() )
74 buffers_.push( factory_.createBuffer() );
75 return (IRecordBuffer)buffers_.peek();
76 }
77
78 /***
79 * {@inheritDoc}
80 */
81 public void previous()
82 {
83 if( buffers_.size() > 1 )
84 {
85 getBuffer().persist();
86 buffers_.insertElementAt( buffers_.pop(), 0 );
87 getBuffer().restore();
88 }
89 }
90
91 /***
92 * {@inheritDoc}
93 */
94 public void next()
95 {
96 if( buffers_.size() > 1 )
97 {
98 getBuffer().persist();
99 final Object next = buffers_.firstElement();
100 buffers_.removeElementAt( 0 );
101 buffers_.push( next );
102 getBuffer().restore();
103 }
104 }
105
106 /***
107 * {@inheritDoc}
108 */
109 public void open()
110 {
111 getBuffer().persist();
112 buffers_.push( factory_.createBuffer() );
113 }
114
115 /***
116 * {@inheritDoc}
117 */
118 public void open( final IFile file )
119 {
120 getBuffer().persist();
121 final IRecordBuffer buffer = findBuffer( file );
122 if( buffer != null )
123 setBuffer( buffer );
124 else
125 createBuffer( file );
126 }
127
128 private IRecordBuffer findBuffer( final IFile file )
129 {
130 final Enumeration e = buffers_.elements();
131 while( e.hasMoreElements() )
132 {
133 final IRecordBuffer buffer = (IRecordBuffer)e.nextElement();
134 if( buffer.hasFile( file ) )
135 return buffer;
136 }
137 return null;
138 }
139
140 private void setBuffer( final IRecordBuffer buffer )
141 {
142 buffers_.removeElement( buffer );
143 buffers_.push( buffer );
144 getBuffer().restore();
145 }
146
147 private void createBuffer( final IFile file )
148 {
149 final IRecordBuffer buffer = factory_.createBuffer();
150 buffer.open( file );
151 buffers_.push( buffer );
152 }
153
154 /***
155 * {@inheritDoc}
156 */
157 public void close()
158 {
159 getBuffer().delete();
160 buffers_.pop();
161 getBuffer().restore();
162 }
163
164 /***
165 * {@inheritDoc}
166 */
167 public boolean save()
168 {
169 return getBuffer().save();
170 }
171
172 /***
173 * {@inheritDoc}
174 */
175 public void save( final IFile file )
176 {
177 getBuffer().save( file );
178 }
179
180 /***
181 * {@inheritDoc}
182 */
183 public boolean hasBeenModified()
184 {
185 return getBuffer().hasBeenModified();
186 }
187
188 /***
189 * {@inheritDoc}
190 */
191 public void unmarshall( final InputStream stream ) throws IOException
192 {
193 buffers_.removeAllElements();
194 while( stream.available() > 0 )
195 {
196 final IRecordBuffer buffer = factory_.createBuffer();
197 buffer.readReference( stream );
198 buffers_.push( buffer );
199 }
200 getBuffer().restore();
201 }
202
203 /***
204 * {@inheritDoc}
205 */
206 public void marshall( final OutputStream stream ) throws IOException
207 {
208 getBuffer().persist();
209 final Enumeration e = buffers_.elements();
210 while( e.hasMoreElements() )
211 {
212 final IRecordBuffer buffer = (IRecordBuffer)e.nextElement();
213 buffer.writeReference( stream );
214 }
215 }
216 }