Mercurial > dive4elements > river
comparison flys-artifacts/src/main/java/org/dive4elements/river/artifacts/datacage/templating/BuilderPool.java @ 5831:bd047b71ab37
Repaired internal references
author | Sascha L. Teichmann <teichmann@intevation.de> |
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date | Thu, 25 Apr 2013 12:06:39 +0200 |
parents | flys-artifacts/src/main/java/de/intevation/flys/artifacts/datacage/templating/BuilderPool.java@d38004f0c52f |
children |
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5830:160f53ee0870 | 5831:bd047b71ab37 |
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1 package org.dive4elements.river.artifacts.datacage.templating; | |
2 | |
3 import java.util.ArrayDeque; | |
4 import java.util.Deque; | |
5 import java.util.List; | |
6 import java.util.Map; | |
7 | |
8 import java.sql.SQLException; | |
9 | |
10 import javax.xml.parsers.DocumentBuilder; | |
11 import javax.xml.parsers.DocumentBuilderFactory; | |
12 import javax.xml.parsers.ParserConfigurationException; | |
13 | |
14 import org.apache.log4j.Logger; | |
15 | |
16 import org.w3c.dom.Document; | |
17 import org.w3c.dom.Node; | |
18 | |
19 /** A little round robin pool of builders to mitigate | |
20 * the fact the XML DOM documents are not thread safe. | |
21 */ | |
22 public class BuilderPool | |
23 { | |
24 private static Logger log = Logger.getLogger(BuilderPool.class); | |
25 | |
26 private static final int DEFAULT_POOL_SIZE = 4; | |
27 | |
28 private static final int POOL_SIZE = Math.max( | |
29 Integer.getInteger("flys.datacage.pool.size", DEFAULT_POOL_SIZE), 1); | |
30 | |
31 private Deque<Builder> pool; | |
32 | |
33 public BuilderPool(Document document) { | |
34 this(document, POOL_SIZE); | |
35 } | |
36 | |
37 public BuilderPool(Document document, int poolSize) { | |
38 | |
39 if (log.isDebugEnabled()) { | |
40 log.debug("Create build pool with " + poolSize + " elements."); | |
41 } | |
42 | |
43 pool = new ArrayDeque<Builder>(poolSize); | |
44 for (int i = 0; i < poolSize; ++i) { | |
45 pool.add(new Builder(cloneDocument(document))); | |
46 } | |
47 } | |
48 | |
49 private final static Document cloneDocument(Document document) { | |
50 | |
51 try { | |
52 DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); | |
53 DocumentBuilder db = dbf.newDocumentBuilder(); | |
54 | |
55 Node origRoot = document.getDocumentElement(); | |
56 | |
57 Document copy = db.newDocument(); | |
58 Node copyRoot = copy.importNode(origRoot, true); | |
59 copy.appendChild(copyRoot); | |
60 | |
61 return copy; | |
62 } | |
63 catch (ParserConfigurationException pce) { | |
64 log.error(pce); | |
65 } | |
66 | |
67 log.error("Returning original document. This will lead to threading issues."); | |
68 | |
69 return document; | |
70 } | |
71 | |
72 public void build( | |
73 List<Builder.NamedConnection> connections, | |
74 Node output, | |
75 Map<String, Object> parameters | |
76 ) | |
77 throws SQLException | |
78 { | |
79 Builder builder; | |
80 synchronized (pool) { | |
81 try { | |
82 while ((builder = pool.poll()) == null) { | |
83 pool.wait(); | |
84 } | |
85 } | |
86 catch (InterruptedException ie) { | |
87 log.debug("Waiting for builder interrupted. Build canceled."); | |
88 return; | |
89 } | |
90 } | |
91 try { | |
92 builder.build(connections, output, parameters); | |
93 } | |
94 finally { | |
95 synchronized (pool) { | |
96 pool.add(builder); | |
97 pool.notify(); | |
98 } | |
99 } | |
100 } | |
101 } | |
102 // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf-8 : |