From a2c8cbb97e688871f105220bef7af2f9b4f311e8 Mon Sep 17 00:00:00 2001
From: Tomas Cere <tcere@cisco.com>
Date: Tue, 7 Apr 2015 15:49:33 +0200
Subject: [PATCH] BUG 2954 : Thread local DocumentBuilder's for XmlUtil

Increases performance by reusing cached DocumentBuilder instances.

Change-Id: I5aab6b4caa960878b647e6868377d62dd6262cd9
Signed-off-by: Tomas Cere <tcere@cisco.com>
---
 .../controller/netconf/util/xml/XmlUtil.java  | 31 +++++++++++--------
 1 file changed, 18 insertions(+), 13 deletions(-)

diff --git a/opendaylight/netconf/netconf-util/src/main/java/org/opendaylight/controller/netconf/util/xml/XmlUtil.java b/opendaylight/netconf/netconf-util/src/main/java/org/opendaylight/controller/netconf/util/xml/XmlUtil.java
index 6408fce5d3..65754e6b34 100644
--- a/opendaylight/netconf/netconf-util/src/main/java/org/opendaylight/controller/netconf/util/xml/XmlUtil.java
+++ b/opendaylight/netconf/netconf-util/src/main/java/org/opendaylight/controller/netconf/util/xml/XmlUtil.java
@@ -68,6 +68,22 @@ public final class XmlUtil {
         BUILDER_FACTORY = factory;
     }
 
+    private static final ThreadLocal<DocumentBuilder> DEFAULT_DOM_BUILDER = new ThreadLocal<DocumentBuilder>(){
+        @Override
+        protected DocumentBuilder initialValue() {
+            try {
+                return BUILDER_FACTORY.newDocumentBuilder();
+            } catch (ParserConfigurationException e) {
+                throw new IllegalStateException("Failed to create threadLocal dom builder", e);
+            }
+        }
+
+        @Override
+        public void set(DocumentBuilder value) {
+            throw new UnsupportedOperationException();
+        }
+    };
+
     private XmlUtil() {
         throw new UnsupportedOperationException("Utility class");
     }
@@ -90,13 +106,7 @@ public final class XmlUtil {
     // along with XmlElement
 
     public static Document readXmlToDocument(final InputStream xmlContent) throws SAXException, IOException {
-        DocumentBuilder dBuilder;
-        try {
-            dBuilder = BUILDER_FACTORY.newDocumentBuilder();
-        } catch (ParserConfigurationException e) {
-            throw new IllegalStateException("Failed to parse XML document", e);
-        }
-        Document doc = dBuilder.parse(xmlContent);
+        Document doc = DEFAULT_DOM_BUILDER.get().parse(xmlContent);
 
         doc.getDocumentElement().normalize();
         return doc;
@@ -107,12 +117,7 @@ public final class XmlUtil {
     }
 
     public static Document newDocument() {
-        try {
-            DocumentBuilder builder = BUILDER_FACTORY.newDocumentBuilder();
-            return builder.newDocument();
-        } catch (ParserConfigurationException e) {
-            throw new IllegalStateException("Failed to create document", e);
-        }
+        return DEFAULT_DOM_BUILDER.get().newDocument();
     }
 
     public static Element createElement(final Document document, final String qName, final Optional<String> namespaceURI) {
-- 
2.36.6