AreaWriter


1   /**
2    * com.mckoi.store.AreaWriter  07 Jun 2003
3    *
4    * Mckoi SQL Database ( http://www.mckoi.com/database )
5    * Copyright (C) 2000, 2001, 2002  Diehl and Associates, Inc.
6    *
7    * This program is free software; you can redistribute it and/or
8    * modify it under the terms of the GNU General Public License
9    * Version 2 as published by the Free Software Foundation.
10   *
11   * This program is distributed in the hope that it will be useful,
12   * but WITHOUT ANY WARRANTY; without even the implied warranty of
13   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14   * GNU General Public License Version 2 for more details.
15   *
16   * You should have received a copy of the GNU General Public License
17   * Version 2 along with this program; if not, write to the Free Software
18   * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
19   *
20   * Change Log:
21   * 
22   * 
23   */
24  
25  package com.mckoi.store;
26  
27  import java.io.OutputStream  ;
28  import java.io.IOException  ;
29  
30  /**
31   * The interface used for setting up an area initially in a store.  This method
32   * is intended to optimize the area creation process.  Typically an area is
33   * created at a specified size and filled with data.  This area should be
34   * used as follows;
35   * <p><pre>
36   *    AreaWriter writer = store.createArea(16);
37   *    writer.putInt(3);
38   *    writer.putLong(100030);
39   *    writer.putByte(1);
40   *    writer.putShort(0);
41   *    writer.putByte(2);
42   *    writer.finish();
43   * </pre></p>
44   * When the 'finish' method is called, the AreaWriter object is invalidated and
45   * the area can then be accessed in the store by the 'getArea' method.
46   * <p>
47   * Note that an area may only be written sequentially using this object.  This
48   * is by design and allows for the area initialization process to be optimized.
49   *
50   * @author Tobias Downer
51   */
52  
53  public interface AreaWriter {
54  
55    /**
56     * Returns the unique identifier that represents this area in the store.
57     */
58    long getID();
59  
60    /**
61     * Returns an OutputStream that can be used to write to this area.  This
62     * stream is backed by this area writer, so if 10 bytes area written to the
63     * output stream then the writer position is also incremented by 10 bytes.
64     */
65    OutputStream   getOutputStream();
66    
67    /**
68     * Returns the size of this area.
69     */
70    int capacity();
71  
72    /**
73     * Finishes the area writer object.  This must be called when the area is
74     * completely initialized.  After this method is called the object is
75     * invalidated and the area can be accessed in the store.
76     */
77    void finish() throws IOException  ;
78  
79    // ---------- Various put methods ----------
80  
81    void put(byte b) throws IOException  ;
82  
83    void put(byte[] buf, int off, int len) throws IOException  ;
84    
85    void put(byte[] buf) throws IOException  ;
86  
87    void putShort(short s) throws IOException  ;
88  
89    void putInt(int i) throws IOException  ;
90  
91    void putLong(long l) throws IOException  ;
92  
93    void putChar(char c) throws IOException  ;  
94  
95  }
96  
97
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