01: /*
02: * Copyright (c) 1998-2008 Caucho Technology -- all rights reserved
03: *
04: * This file is part of Resin(R) Open Source
05: *
06: * Each copy or derived work must preserve the copyright notice and this
07: * notice unmodified.
08: *
09: * Resin Open Source is free software; you can redistribute it and/or modify
10: * it under the terms of the GNU General Public License as published by
11: * the Free Software Foundation; either version 2 of the License, or
12: * (at your option) any later version.
13: *
14: * Resin Open Source 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, or any warranty
17: * of NON-INFRINGEMENT. See the GNU General Public License for more
18: * details.
19: *
20: * You should have received a copy of the GNU General Public License
21: * along with Resin Open Source; if not, write to the
22: * Free Software Foundation, Inc.
23: * 59 Temple Place, Suite 330
24: * Boston, MA 02111-1307 USA
25: *
26: * @author Scott Ferguson
27: */
28:
29: package com.caucho.amber.idgen;
30:
31: import com.caucho.amber.manager.AmberConnection;
32: import com.caucho.util.L10N;
33: import com.caucho.util.Log;
34:
35: import java.sql.SQLException;
36: import java.util.logging.Logger;
37:
38: /**
39: * Generator table.
40: */
41: abstract public class IdGenerator {
42: private static final L10N L = new L10N(IdGenerator.class);
43: private static final Logger log = Log.open(IdGenerator.class);
44:
45: private long _next;
46: private int _remaining;
47:
48: private int _groupSize = 50;
49:
50: /**
51: * Gets the group size.
52: */
53: public int getGroupSize() {
54: return _groupSize;
55: }
56:
57: /**
58: * Sets the group size.
59: */
60: public void setGroupSize(int groupSize) {
61: _groupSize = groupSize;
62: }
63:
64: /**
65: * Allocates the next id.
66: */
67: public long allocate(AmberConnection aConn) throws SQLException {
68: synchronized (this ) {
69: if (_remaining <= 0) {
70: _next = allocateGroup(aConn);
71: _remaining += getGroupSize();
72: }
73:
74: long value = _next;
75: _next++;
76: _remaining--;
77:
78: return value;
79: }
80: }
81:
82: /**
83: * Allocates the next group of ids.
84: */
85: abstract public long allocateGroup(AmberConnection aConn)
86: throws SQLException;
87: }
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