Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||
HiLoGenerator |
|
| 1.2857142857142858;1.286 |
1 | /** | |
2 | The contents of this file are subject to the Mozilla Public License Version 1.1 | |
3 | (the "License"); you may not use this file except in compliance with the License. | |
4 | You may obtain a copy of the License at http://www.mozilla.org/MPL/ | |
5 | Software distributed under the License is distributed on an "AS IS" basis, | |
6 | WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for the | |
7 | specific language governing rights and limitations under the License. | |
8 | ||
9 | The Original Code is "HiLoGenerator.java". Description: | |
10 | "Abstract base class for HiLo ID Generators" | |
11 | ||
12 | The Initial Developer of the Original Code is University Health Network. Copyright (C) | |
13 | 2001. All Rights Reserved. | |
14 | ||
15 | Contributor(s): ______________________________________. | |
16 | ||
17 | Alternatively, the contents of this file may be used under the terms of the | |
18 | GNU General Public License (the "GPL"), in which case the provisions of the GPL are | |
19 | applicable instead of those above. If you wish to allow use of your version of this | |
20 | file only under the terms of the GPL and not to allow others to use your version | |
21 | of this file under the MPL, indicate your decision by deleting the provisions above | |
22 | and replace them with the notice and other provisions required by the GPL License. | |
23 | If you do not delete the provisions above, a recipient may use your version of | |
24 | this file under either the MPL or the GPL. | |
25 | */ | |
26 | package ca.uhn.hl7v2.util.idgenerator; | |
27 | ||
28 | import java.io.IOException; | |
29 | ||
30 | import org.slf4j.Logger; | |
31 | import org.slf4j.LoggerFactory; | |
32 | ||
33 | /** | |
34 | * Abstract base class for a HiLo-style generator that cheaply generates "lo" | |
35 | * IDs in memory but only seldomly increments (potentially more expensive) a | |
36 | * "hi" ID, e.g. in a persistent store. The combination of "lo" and "hi" ID | |
37 | * becomes the final ID returned to the caller. | |
38 | * | |
39 | * @author Christian Ohr | |
40 | */ | |
41 | 5530 | public abstract class HiLoGenerator extends IDGenerator.OrderedSupport { |
42 | ||
43 | 10 | private static final Logger LOG = LoggerFactory |
44 | 5 | .getLogger(HiLoGenerator.class.getName()); |
45 | ||
46 | 5530 | private long lo = 0L; |
47 | 5530 | private long base = -1L; |
48 | ||
49 | public synchronized String getID() throws IOException { | |
50 | 7433 | if (base < 0) { |
51 | 830 | LOG.debug("Obtain next hi ID"); |
52 | 830 | base = nextBase(); |
53 | } | |
54 | 7433 | if (getNextLoId() >= getMaxLo()) { |
55 | 60 | LOG.debug("Obtain next hi ID"); |
56 | 60 | base = nextBase(); |
57 | } | |
58 | 7433 | return Long.toString(base + lo); |
59 | } | |
60 | ||
61 | private long nextBase() throws IOException { | |
62 | 890 | long base = getNextHiId(); |
63 | 890 | lo = 0; |
64 | 890 | return base; |
65 | } | |
66 | ||
67 | /** | |
68 | * Returns the next Hi ID | |
69 | * @return the next Hi ID | |
70 | * @throws IOException | |
71 | */ | |
72 | protected abstract long getNextHiId() throws IOException; | |
73 | ||
74 | /** | |
75 | * Resets the Hi ID | |
76 | */ | |
77 | protected abstract void resetHiId(); | |
78 | ||
79 | /** | |
80 | * Returns then next Lo ID | |
81 | * @return | |
82 | */ | |
83 | protected long getNextLoId() { | |
84 | 7433 | return ++lo; |
85 | } | |
86 | ||
87 | /** | |
88 | * Resets the generator | |
89 | */ | |
90 | public void reset() { | |
91 | 10 | lo = 0; |
92 | 10 | base = -1; |
93 | 10 | resetHiId(); |
94 | 10 | } |
95 | ||
96 | /** | |
97 | * Returns the maximum Lo ID (expect the Hi ID be incremented afterwards) | |
98 | * @return the maximum Lo ID | |
99 | */ | |
100 | abstract public long getMaxLo(); | |
101 | ||
102 | } |