[#1384] Cache HttpHeaderDateFormat in ThreadLocal

codec-http/src/main/java/io/netty/handler/codec/http/CookieDecoder.java

@@ -117,7 +117,7 @@ public final class CookieDecoder {
                 } else if (CookieHeaderNames.EXPIRES.equalsIgnoreCase(name)) {
                     try {
                         long maxAgeMillis =
-                            new HttpHeaderDateFormat().parse(value).getTime() -
+                            HttpHeaderDateFormat.get().parse(value).getTime() -
                             System.currentTimeMillis();
 
                         maxAge = maxAgeMillis / 1000 + (maxAgeMillis % 1000 != 0? 1 : 0);

codec-http/src/main/java/io/netty/handler/codec/http/DefaultHttpHeaders.java

@@ -304,10 +304,10 @@ public class DefaultHttpHeaders extends HttpHeaders {
             return value.toString();
         }
         if (value instanceof Date) {
-            return new HttpHeaderDateFormat().format((Date) value);
+            return HttpHeaderDateFormat.get().format((Date) value);
         }
         if (value instanceof Calendar) {
-            return new HttpHeaderDateFormat().format(((Calendar) value).getTime());
+            return HttpHeaderDateFormat.get().format(((Calendar) value).getTime());
         }
         return value.toString();
     }

codec-http/src/main/java/io/netty/handler/codec/http/HttpHeaderDateFormat.java

@@ -37,11 +37,22 @@ final class HttpHeaderDateFormat extends SimpleDateFormat {
     private final SimpleDateFormat format1 = new HttpHeaderDateFormatObsolete1();
     private final SimpleDateFormat format2 = new HttpHeaderDateFormatObsolete2();
 
+    private static ThreadLocal<HttpHeaderDateFormat> dateFormatThreadLocal = new ThreadLocal<HttpHeaderDateFormat>() {
+        @Override
+        protected HttpHeaderDateFormat initialValue() {
+            return new HttpHeaderDateFormat();
+        }
+    };
+
+    static HttpHeaderDateFormat get() {
+        return dateFormatThreadLocal.get();
+    }
+
     /**
      * Standard date format<p>
      * Sun, 06 Nov 1994 08:49:37 GMT -> E, d MMM yyyy HH:mm:ss z
      */
-    HttpHeaderDateFormat() {
+    private HttpHeaderDateFormat() {
         super("E, dd MMM yyyy HH:mm:ss z", Locale.ENGLISH);
         setTimeZone(TimeZone.getTimeZone("GMT"));
     }

codec-http/src/main/java/io/netty/handler/codec/http/HttpHeaders.java

@@ -750,7 +750,7 @@ public abstract class HttpHeaders implements Iterable<Map.Entry<String, String>>
         if (value == null) {
             throw new ParseException("header not found: " + name, 0);
         }
-        return new HttpHeaderDateFormat().parse(value);
+        return HttpHeaderDateFormat.get().parse(value);
     }
 
     /**
@@ -768,7 +768,7 @@ public abstract class HttpHeaders implements Iterable<Map.Entry<String, String>>
         }
 
         try {
-            return new HttpHeaderDateFormat().parse(value);
+            return HttpHeaderDateFormat.get().parse(value);
         } catch (ParseException e) {
             return defaultValue;
         }
@@ -782,7 +782,7 @@ public abstract class HttpHeaders implements Iterable<Map.Entry<String, String>>
      */
     public static void setDateHeader(HttpMessage message, String name, Date value) {
         if (value != null) {
-            message.headers().set(name, new HttpHeaderDateFormat().format(value));
+            message.headers().set(name, HttpHeaderDateFormat.get().format(value));
         } else {
             message.headers().set(name, null);
         }
@@ -947,7 +947,7 @@ public abstract class HttpHeaders implements Iterable<Map.Entry<String, String>>
      */
     public static void setDate(HttpMessage message, Date value) {
         if (value != null) {
-            message.headers().set(Names.DATE, new HttpHeaderDateFormat().format(value));
+            message.headers().set(Names.DATE, HttpHeaderDateFormat.get().format(value));
         } else {
             message.headers().set(Names.DATE, null);
         }

codec-http/src/main/java/io/netty/handler/codec/http/ServerCookieEncoder.java

@@ -54,7 +54,7 @@ public final class ServerCookieEncoder {
         if (cookie.getMaxAge() != Long.MIN_VALUE) {
             if (cookie.getVersion() == 0) {
                 addUnquoted(buf, CookieHeaderNames.EXPIRES,
-                        new HttpHeaderDateFormat().format(
+                        HttpHeaderDateFormat.get().format(
                                 new Date(System.currentTimeMillis() +
                                          cookie.getMaxAge() * 1000L)));
             } else {

codec-http/src/test/java/io/netty/handler/codec/http/CookieDecoderTest.java

@@ -30,7 +30,7 @@ public class CookieDecoderTest {
     public void testDecodingSingleCookieV0() {
         String cookieString = "myCookie=myValue;expires=XXX;path=/apathsomewhere;domain=.adomainsomewhere;secure;";
         cookieString = cookieString.replace("XXX",
-                new HttpHeaderDateFormat().format(new Date(System.currentTimeMillis() + 50000)));
+                HttpHeaderDateFormat.get().format(new Date(System.currentTimeMillis() + 50000)));
 
         Set<Cookie> cookies = CookieDecoder.decode(cookieString);
         assertEquals(1, cookies.size());

codec-http/src/test/java/io/netty/handler/codec/http/CookieEncoderTest.java

@@ -27,7 +27,7 @@ public class CookieEncoderTest {
     @Test
     public void testEncodingSingleCookieV0() {
         String result = "myCookie=myValue; Expires=XXX; Path=/apathsomewhere; Domain=.adomainsomewhere; Secure";
-        DateFormat df = new HttpHeaderDateFormat();
+        DateFormat df = HttpHeaderDateFormat.get();
         Cookie cookie = new DefaultCookie("myCookie", "myValue");
         cookie.setComment("this is a Comment");
         cookie.setCommentUrl("http://aurl.com");

codec-http/src/test/java/io/netty/handler/codec/http/HttpHeaderDateFormatTest.java

@@ -32,7 +32,7 @@ public class HttpHeaderDateFormatTest {
 
     @Test
     public void testParse() throws ParseException {
-        HttpHeaderDateFormat format = new HttpHeaderDateFormat();
+        HttpHeaderDateFormat format = HttpHeaderDateFormat.get();
 
         final Date parsedDateWithSingleDigitDay = format.parse("Sun, 6 Nov 1994 08:49:37 GMT");
         Assert.assertNotNull(parsedDateWithSingleDigitDay);
@@ -61,7 +61,7 @@ public class HttpHeaderDateFormatTest {
 
     @Test
     public void testFormat() {
-        HttpHeaderDateFormat format = new HttpHeaderDateFormat();
+        HttpHeaderDateFormat format = HttpHeaderDateFormat.get();
 
         final String formatted = format.format(DATE);
         Assert.assertNotNull(formatted);