From: Tony Tkacik <ttkacik@cisco.com>
Date: Mon, 15 Dec 2014 07:51:47 +0000 (+0000)
Subject: Merge "BUG-2459: use thread-local cache of transformers"
X-Git-Tag: release/lithium~770
X-Git-Url: https://git.opendaylight.org/gerrit/gitweb?p=controller.git;a=commitdiff_plain;h=da7b79cbf4b48a928910796150da4cb128848783;hp=5834d6db8a5b2f56ec469ceafd899a94a69f7b91

Merge "BUG-2459: use thread-local cache of transformers"
---

diff --git a/opendaylight/netconf/netconf-netty-util/src/main/java/org/opendaylight/controller/netconf/nettyutil/handler/NetconfMessageToEXIEncoder.java b/opendaylight/netconf/netconf-netty-util/src/main/java/org/opendaylight/controller/netconf/nettyutil/handler/NetconfMessageToEXIEncoder.java
index 55dcd9daba..f1e72ed85f 100644
--- a/opendaylight/netconf/netconf-netty-util/src/main/java/org/opendaylight/controller/netconf/nettyutil/handler/NetconfMessageToEXIEncoder.java
+++ b/opendaylight/netconf/netconf-netty-util/src/main/java/org/opendaylight/controller/netconf/nettyutil/handler/NetconfMessageToEXIEncoder.java
@@ -14,11 +14,9 @@ import io.netty.channel.ChannelHandlerContext;
 import io.netty.handler.codec.MessageToByteEncoder;
 import java.io.IOException;
 import java.io.OutputStream;
-import javax.xml.transform.Transformer;
 import javax.xml.transform.TransformerException;
 import javax.xml.transform.dom.DOMSource;
 import javax.xml.transform.sax.SAXResult;
-import javax.xml.transform.sax.SAXTransformerFactory;
 import org.opendaylight.controller.netconf.api.NetconfMessage;
 import org.openexi.proc.common.EXIOptionsException;
 import org.openexi.sax.Transmogrifier;
@@ -26,10 +24,7 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 public final class NetconfMessageToEXIEncoder extends MessageToByteEncoder<NetconfMessage> {
-
     private static final Logger LOG = LoggerFactory.getLogger(NetconfMessageToEXIEncoder.class);
-
-    private static final SAXTransformerFactory saxTransformerFactory = (SAXTransformerFactory)SAXTransformerFactory.newInstance();
     private final NetconfEXICodec codec;
 
     public NetconfMessageToEXIEncoder(final NetconfEXICodec codec) {
@@ -44,8 +39,7 @@ public final class NetconfMessageToEXIEncoder extends MessageToByteEncoder<Netco
             final Transmogrifier transmogrifier = codec.getTransmogrifier();
             transmogrifier.setOutputStream(os);
 
-            final Transformer transformer = saxTransformerFactory.newTransformer();
-            transformer.transform(new DOMSource(msg.getDocument()), new SAXResult(transmogrifier.getSAXTransmogrifier()));
+            ThreadLocalTransformers.getDefaultTransformer().transform(new DOMSource(msg.getDocument()), new SAXResult(transmogrifier.getSAXTransmogrifier()));
         }
     }
 }
diff --git a/opendaylight/netconf/netconf-netty-util/src/main/java/org/opendaylight/controller/netconf/nettyutil/handler/NetconfMessageToXMLEncoder.java b/opendaylight/netconf/netconf-netty-util/src/main/java/org/opendaylight/controller/netconf/nettyutil/handler/NetconfMessageToXMLEncoder.java
index d109e2df4a..99251b00d4 100644
--- a/opendaylight/netconf/netconf-netty-util/src/main/java/org/opendaylight/controller/netconf/nettyutil/handler/NetconfMessageToXMLEncoder.java
+++ b/opendaylight/netconf/netconf-netty-util/src/main/java/org/opendaylight/controller/netconf/nettyutil/handler/NetconfMessageToXMLEncoder.java
@@ -17,10 +17,7 @@ import java.io.BufferedWriter;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.io.OutputStreamWriter;
-import javax.xml.transform.OutputKeys;
-import javax.xml.transform.Transformer;
 import javax.xml.transform.TransformerException;
-import javax.xml.transform.TransformerFactory;
 import javax.xml.transform.dom.DOMSource;
 import javax.xml.transform.stream.StreamResult;
 import org.opendaylight.controller.netconf.api.NetconfMessage;
@@ -30,7 +27,6 @@ import org.w3c.dom.Comment;
 
 public class NetconfMessageToXMLEncoder extends MessageToByteEncoder<NetconfMessage> {
     private static final Logger LOG = LoggerFactory.getLogger(NetconfMessageToXMLEncoder.class);
-    private static final TransformerFactory FACTORY = TransformerFactory.newInstance();
 
     private final Optional<String> clientId;
 
@@ -38,13 +34,13 @@ public class NetconfMessageToXMLEncoder extends MessageToByteEncoder<NetconfMess
         this(Optional.<String>absent());
     }
 
-    public NetconfMessageToXMLEncoder(Optional<String> clientId) {
+    public NetconfMessageToXMLEncoder(final Optional<String> clientId) {
         this.clientId = clientId;
     }
 
     @Override
     @VisibleForTesting
-    public void encode(ChannelHandlerContext ctx, NetconfMessage msg, ByteBuf out) throws IOException, TransformerException {
+    public void encode(final ChannelHandlerContext ctx, final NetconfMessage msg, final ByteBuf out) throws IOException, TransformerException {
         LOG.trace("Sent to encode : {}", msg);
 
         if (clientId.isPresent()) {
@@ -53,14 +49,10 @@ public class NetconfMessageToXMLEncoder extends MessageToByteEncoder<NetconfMess
         }
 
         try (OutputStream os = new ByteBufOutputStream(out)) {
-            Transformer transformer = FACTORY.newTransformer();
-            transformer.setOutputProperty(OutputKeys.INDENT, "yes");
-            transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
-
             // Wrap OutputStreamWriter with BufferedWriter as suggested in javadoc for OutputStreamWriter
             StreamResult result = new StreamResult(new BufferedWriter(new OutputStreamWriter(os)));
             DOMSource source = new DOMSource(msg.getDocument());
-            transformer.transform(source, result);
+            ThreadLocalTransformers.getPrettyTransformer().transform(source, result);
         }
     }
 }
diff --git a/opendaylight/netconf/netconf-netty-util/src/main/java/org/opendaylight/controller/netconf/nettyutil/handler/ThreadLocalTransformers.java b/opendaylight/netconf/netconf-netty-util/src/main/java/org/opendaylight/controller/netconf/nettyutil/handler/ThreadLocalTransformers.java
new file mode 100644
index 0000000000..a2039d6fe9
--- /dev/null
+++ b/opendaylight/netconf/netconf-netty-util/src/main/java/org/opendaylight/controller/netconf/nettyutil/handler/ThreadLocalTransformers.java
@@ -0,0 +1,82 @@
+/*
+ * Copyright (c) 2014 Cisco Systems, Inc. and others.  All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v1.0 which accompanies this distribution,
+ * and is available at http://www.eclipse.org/legal/epl-v10.html
+ */
+package org.opendaylight.controller.netconf.nettyutil.handler;
+
+import javax.xml.transform.OutputKeys;
+import javax.xml.transform.Transformer;
+import javax.xml.transform.TransformerConfigurationException;
+import javax.xml.transform.TransformerFactory;
+import javax.xml.transform.TransformerFactoryConfigurationError;
+
+/**
+ * Utility class for cached thread-local transformers. This class exists mostly for use by handlers.
+ */
+final class ThreadLocalTransformers {
+    private static final TransformerFactory FACTORY = TransformerFactory.newInstance();
+
+    private static final ThreadLocal<Transformer> DEFAULT_TRANSFORMER = new ThreadLocal<Transformer>() {
+        @Override
+        protected Transformer initialValue() {
+            try {
+                return FACTORY.newTransformer();
+            } catch (TransformerConfigurationException | TransformerFactoryConfigurationError e) {
+                throw new IllegalStateException("Unexpected error while instantiating a Transformer", e);
+            }
+        };
+
+        @Override
+        public void set(final Transformer value) {
+            throw new UnsupportedOperationException();
+        };
+    };
+
+    private static final ThreadLocal<Transformer> PRETTY_TRANSFORMER = new ThreadLocal<Transformer>() {
+        @Override
+        protected Transformer initialValue() {
+            final Transformer ret;
+
+            try {
+                ret = FACTORY.newTransformer();
+            } catch (TransformerConfigurationException | TransformerFactoryConfigurationError e) {
+                throw new IllegalStateException("Unexpected error while instantiating a Transformer", e);
+            }
+
+            ret.setOutputProperty(OutputKeys.INDENT, "yes");
+            ret.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
+            return ret;
+        };
+
+        @Override
+        public void set(final Transformer value) {
+            throw new UnsupportedOperationException();
+        };
+    };
+
+    private ThreadLocalTransformers() {
+        throw new UnsupportedOperationException("Utility class");
+    }
+
+    /**
+     * Get the transformer with default configuration.
+     *
+     * @return A transformer with default configuration based on the default implementation.
+     */
+    public static Transformer getDefaultTransformer() {
+        return DEFAULT_TRANSFORMER.get();
+    }
+
+    /**
+     * Get the transformer with default configuration, but with automatic indentation
+     * and the XML declaration removed.
+     *
+     * @return A transformer with human-friendly configuration.
+     */
+    public static Transformer getPrettyTransformer() {
+        return PRETTY_TRANSFORMER.get();
+    }
+}