BCursor


1   package com.quadcap.sql.index;
2   
3   /* Copyright 1997 - 2003 Quadcap Software.  All rights reserved.
4    *
5    * This software is distributed under the Quadcap Free Software License.
6    * This software may be used or modified for any purpose, personal or
7    * commercial.  Open Source redistributions are permitted.  Commercial
8    * redistribution of larger works derived from, or works which bundle
9    * this software requires a "Commercial Redistribution License"; see
10   * http://www.quadcap.com/purchase.
11   *
12   * Redistributions qualify as "Open Source" under  one of the following terms:
13   *   
14   *    Redistributions are made at no charge beyond the reasonable cost of
15   *    materials and delivery.
16   *
17   *    Redistributions are accompanied by a copy of the Source Code or by an
18   *    irrevocable offer to provide a copy of the Source Code for up to three
19   *    years at the cost of materials and delivery.  Such redistributions
20   *    must allow further use, modification, and redistribution of the Source
21   *    Code under substantially the same terms as this license.
22   *
23   * Redistributions of source code must retain the copyright notices as they
24   * appear in each source code file, these license terms, and the
25   * disclaimer/limitation of liability set forth as paragraph 6 below.
26   *
27   * Redistributions in binary form must reproduce this Copyright Notice,
28   * these license terms, and the disclaimer/limitation of liability set
29   * forth as paragraph 6 below, in the documentation and/or other materials
30   * provided with the distribution.
31   *
32   * The Software is provided on an "AS IS" basis.  No warranty is
33   * provided that the Software is free of defects, or fit for a
34   * particular purpose.  
35   *
36   * Limitation of Liability. Quadcap Software shall not be liable
37   * for any damages suffered by the Licensee or any third party resulting
38   * from use of the Software.
39   */
40  
41  import java.io.IOException  ;
42  
43  /**
44   * BCursor
45   *
46   * @author Stan Bailes
47   */
48  public interface BCursor {
49      // Cursor positioning
50  
51      /**
52       * Seek to (before) the specified key
53       */
54      boolean seek(byte[] key, int len) throws IOException  ;
55  
56      /**
57       * Seek to (before) the specified key
58       */
59      boolean seek(byte[] buf) throws IOException  ;
60  
61      /**
62       * Position cursor before the first record
63       */
64      void beforeFirst() throws IOException  ;
65  
66      /**
67       * Position the cursor after the last record
68       */
69      void afterLast() throws IOException  ;
70  
71      /**
72       * Move to the specified record; one-based.
73       * -1 means last record, -2 means next to last, etc.
74       * @return <b>true</b> if the specified record exists.     
75       */
76      boolean absolute(int x) throws IOException  ;
77  
78      /**
79       * Move past the next record and return true the cursor is
80       * now pointed at a valid record.
81       */
82      boolean next() throws IOException  ;
83  
84      /**
85       * Move before the previous record and return true the cursor is
86       * now pointed at a valid record.
87       */
88      boolean prev() throws IOException  ;
89  
90      int getKey(byte[] buf) throws IOException  ;
91      byte[] getKeyBuf();
92      void setKeyBuf(byte[] buf);
93      int getKeyLen();
94      byte[] getKey();                    // XXX a crutch.
95      
96      int getVal(byte[] buf) throws IOException  ;
97      byte[] getValBuf();
98      void setValBuf(byte[] buf);
99      int getValLen();
100     byte[] getVal();                    // XXX a crutch.
101     
102     long getValAsLong() throws IOException  ;
103 
104     long size() throws IOException  ;
105     long position() throws IOException  ;
106 
107     /**
108      * Release this cursor back to the pool
109      */
110     void release();
111 
112     /**
113      * Release any resources held by this cursor (but maintain ownership of
114      * it -- it can be resurrected by another positioning call.
115      */
116     void close() throws IOException  ;
117 
118     /**
119      * Delete the currently positioned record
120      */
121     boolean delete() throws IOException  ;
122 
123     /**
124      * Insert a new key/data pair.  We are presumably positioned just before
125      * the spot where the new record should go, but we will check, anyway.
126      */
127     boolean insert(byte[] key, int klen,
128                    byte[] data, int doff, int dlen) throws IOException  ;
129     boolean insert(byte[] key, byte[] data) throws IOException  ;
130 
131     /**
132      * Replace the data portion of the current item with the specified data
133      */
134     boolean replace(byte[] data, int doff, int dlen) throws IOException  ;
135     boolean replace(byte[] data) throws IOException  ;
136 
137 }
138
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