Mercurial > dive4elements > river
comparison artifacts/src/main/java/org/dive4elements/river/artifacts/datacage/templating/BuilderPool.java @ 5838:5aa05a7a34b7
Rename modules to more fitting names.
| author | Sascha L. Teichmann <teichmann@intevation.de> |
|---|---|
| date | Thu, 25 Apr 2013 15:23:37 +0200 |
| parents | flys-artifacts/src/main/java/org/dive4elements/river/artifacts/datacage/templating/BuilderPool.java@bd047b71ab37 |
| children | 4897a58c8746 |
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| 5837:d9901a08d0a6 | 5838:5aa05a7a34b7 |
|---|---|
| 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 : |