Commit Graph

585 Commits

Author SHA1 Message Date
Matteo Merli
9b45e9d015 Additional configuration for leak detection
Motivation:

Leak detector, when it detects a leak, will print the last 5 stack
traces that touched the ByteBuf. In some cases that might not be enough
to identify the root cause of the leak.
Also, sometimes users might not be interested in tracing all the
operations on the buffer, but just the ones that are affecting the
reference count.

Modifications:

Added command line properties to override default values:
 * Allow to configure max number of stack traces to collect
 * Allow to only record retain/release operation on buffers

Result:
Users can increase the number of stack traces to debug buffer leaks
with lot of retain/release operations.
2015-08-30 20:50:10 +02:00
Norman Maurer
1252f74528 [#4171] Fix flacky test introduced by previous commit.
Motivation:

SingleThreadEventExecutorTest was flacky.

Modifications:

Fixed flacky test.

Result:

No more test failures
2015-08-29 12:30:35 +02:00
Norman Maurer
6d473e7f39 Allow to get details of the Thread that powers a SingleThreadEventExecutor.
Motivation:

for debugging and metrics reasons its sometimes useful to be able to get details of the the Thread that powers a SingleThreadEventExecutor.

Modifications:

- Expose ThreadProperties
- Add unit test.

Result:

It's now possible to get details of the Thread that powers a SingleThreadEventExecutor.
2015-08-28 15:34:19 +02:00
Norman Maurer
1a9ea2d349 [#4147] Allow to disable recycling
Motivation:

Sometimes it is useful to disable recycling completely if memory constraints are very tight.

Modifications:

Allow to use -Dio.netty.recycler.maxCapacity=0 to disable recycling completely.

Result:

It's possible to disable recycling now.
2015-08-28 15:05:17 +02:00
Norman Maurer
eb1c97b3b9 [#4110] Correct javadocs of MpscLinkedQueue
Motivation:

The javadocs are incorrect and so give false impressions of use-pattern.

Modifications:

- Fix javadocs of which operations are allowed from multiple threads concurrently.
- Let isEmpty() work concurrently.

Result:

Correctly document usage-patterns.
2015-08-27 09:09:28 +02:00
Scott Mitchell
cbc38e938a UNSAFE.throwException null arg crashes JVM
Motivation:
It has been observed that passing a null argument to Unsafe.throwException can crash the JVM.

Modifications:
- PlatformUnsafe0.throwException should honor http://docs.oracle.com/javase/specs/jls/se8/html/jls-14.html#jls-14.18 and throw a NPE

Result:
No risk of JVM crashing for null argument.
Fixes https://github.com/netty/netty/issues/4131
2015-08-26 23:50:51 -07:00
Scott Mitchell
9bc322a6a8 StringUtil not closing Formatter
Motivation:
The StringUtil class creates a Formatter object, but does not close it. There are also a 2 utility methods which would be generally useful.

Modifications:
- Close the Formatter
- Add length and isNullOrEmpty

Result:
No more resource leaks. Additional utility methods.
2015-08-20 09:44:31 -07:00
Scott Mitchell
ba6ce5449e Headers Performance Boost and Interface Simplification
Motivation:
A degradation in performance has been observed from the 4.0 branch as documented in https://github.com/netty/netty/issues/3962.

Modifications:
- Simplify Headers class hierarchy.
- Restore the DefaultHeaders to be based upon DefaultHttpHeaders from 4.0.
- Make various other modifications that are causing hot spots.

Result:
Performance is now on par with 4.0.
2015-08-17 08:50:11 -07:00
Jakob Buchgraber
6fd0a0c55f Faster and more memory efficient headers for HTTP, HTTP/2, STOMP and SPYD. Fixes #3600
Motivation:

We noticed that the headers implementation in Netty for HTTP/2 uses quite a lot of memory
and that also at least the performance of randomly accessing a header is quite poor. The main
concern however was memory usage, as profiling has shown that a DefaultHttp2Headers
not only use a lot of memory it also wastes a lot due to the underlying hashmaps having
to be resized potentially several times as new headers are being inserted.

This is tracked as issue #3600.

Modifications:
We redesigned the DefaultHeaders to simply take a Map object in its constructor and
reimplemented the class using only the Map primitives. That way the implementation
is very concise and hopefully easy to understand and it allows each concrete headers
implementation to provide its own map or to even use a different headers implementation
for processing requests and writing responses i.e. incoming headers need to provide
fast random access while outgoing headers need fast insertion and fast iteration. The
new implementation can support this with hardly any code changes. It also comes
with the advantage that if the Netty project decides to add a third party collections library
as a dependency, one can simply plug in one of those very fast and memory efficient map
implementations and get faster and smaller headers for free.

For now, we are using the JDK's TreeMap for HTTP and HTTP/2 default headers.

Result:

- Significantly fewer lines of code in the implementation. While the total commit is still
  roughly 400 lines less, the actual implementation is a lot less. I just added some more
  tests and microbenchmarks.

- Overall performance is up. The current implementation should be significantly faster
  for insertion and retrieval. However, it is slower when it comes to iteration. There is simply
  no way a TreeMap can have the same iteration performance as a linked list (as used in the
  current headers implementation). That's totally fine though, because when looking at the
  benchmark results @ejona86 pointed out that the performance of the headers is completely
  dominated by insertion, that is insertion is so significantly faster in the new implementation
  that it does make up for several times the iteration speed. You can't iterate what you haven't
  inserted. I am demonstrating that in this spreadsheet [1]. (Actually, iteration performance is
  only down for HTTP, it's significantly improved for HTTP/2).

- Memory is down. The implementation with TreeMap uses on avg ~30% less memory. It also does not
  produce any garbage while being resized. In load tests for GRPC we have seen a memory reduction
  of up to 1.2KB per RPC. I summarized the memory improvements in this spreadsheet [1]. The data
  was generated by [2] using JOL.

- While it was my original intend to only improve the memory usage for HTTP/2, it should be similarly
  improved for HTTP, SPDY and STOMP as they all share a common implementation.

[1] https://docs.google.com/spreadsheets/d/1ck3RQklyzEcCLlyJoqDXPCWRGVUuS-ArZf0etSXLVDQ/edit#gid=0
[2] https://gist.github.com/buchgr/4458a8bdb51dd58c82b4
2015-08-04 17:12:24 -07:00
Ning Sun
9236a8d156 (fix) typo 2015-07-30 12:49:25 +02:00
Scott Mitchell
a7713069a1 HttpObjectDecoder performance improvements
Motivation:
The HttpObjectDecoder is on the hot code path for the http codec. There are a few hot methods which can be modified to improve performance.

Modifications:
- Modify AppendableCharSequence to provide unsafe methods which don't need to re-check bounds for every call.
- Update HttpObjectDecoder methods to take advantage of new AppendableCharSequence methods.

Result:
Peformance boost for decoding http objects.
2015-07-29 23:26:26 -07:00
Daniel Darabos
623d9d7202 Fix typo in warning message. 2015-07-29 18:38:33 +02:00
nmittler
296649cfc8 Make PrimitiveCollections generated for all primitive maps.
Motivation:

We should support XXXCollections methods for all primitive map types.

Modifications:

Removed PrimitiveCollections and added a template for XXXCollections.

Result:

Fixes #4001
2015-07-27 06:59:23 -07:00
nmittler
93fc3c6e45 Make IntObjectHashMap extend Map
Motivation:

It would be useful to support the Java `Map` interface in our primitive maps.

Modifications:

Renamed current methods to "pXXX", where p is short for "primitive". Made the template for all primitive maps extend the appropriate Map interface.

Result:

Fixes #3970
2015-07-22 15:52:27 -07:00
Norman Maurer
05dae57ad7 Ensure cancelled scheduled tasks can be GC'ed ASAP
Motivation:

Prior we used a purge task that would remove previous canceled scheduled tasks from the internal queue. This could introduce some delay and so use a lot of memory even if the task itself is already canceled.

Modifications:

Schedule removal of task from queue via EventLoop if cancel operation is not done in the EventLoop Thread or just remove directly if the Thread that cancels the scheduled task is in the EventLoop.

Result:

Faster possibility to GC a canceled ScheduledFutureTask.
2015-07-19 16:51:12 +02:00
Norman Maurer
81fee66c78 Let PoolThreadCache work even if allocation and deallocation Thread are different
Motivation:

PoolThreadCache did only cache allocations if the allocation and deallocation Thread were the same. This is not optimal as often people write from differen thread then the actual EventLoop thread.

Modification:

- Add MpscArrayQueue which was forked from jctools and lightly modified.
- Use MpscArrayQueue for caches and always add buffer back to the cache that belongs to the allocation thread.

Result:

ThreadPoolCache is now also usable and so gives performance improvements when allocation and deallocation thread are different.

Performance when using same thread for allocation and deallocation is noticable worse then before.
2015-05-27 14:38:11 +02:00
Norman Maurer
08d234cdf0 [#3805] Fix incorrect javadoc in PlatformDependent 2015-05-25 21:42:31 +02:00
Norman Maurer
271af7c624 Expose metrics for PooledByteBufAllocator
Motivation:

The PooledByteBufAllocator is more or less a black-box atm. We need to expose some metrics to allow the user to get a better idea how to tune it.

Modifications:

- Expose different metrics via PooledByteBufAllocator
- Add *Metrics interfaces

Result:

It is now easy to gather metrics and detail about the PooledByteBufAllocator and so get a better understanding about resource-usage etc.
2015-05-20 21:06:17 +02:00
Scott Mitchell
a2cd01b32b ByteString test failure bug
Motivation:
There is an error in the ByteString test logic which is resulting in test failures.

Modifications:
- Fix the loop iteration to use the loop iteration variable instead of a fixed index.

Result:
Tests are less buggy.
2015-05-08 09:44:02 -07:00
Norman Maurer
f23b7b4efd [maven-release-plugin] prepare for next development iteration 2015-05-07 14:21:08 -04:00
Norman Maurer
871ce43b1f [maven-release-plugin] prepare release netty-4.1.0.Beta5 2015-05-07 14:20:38 -04:00
Norman Maurer
e71e40057f Fix possible IllegalStateException caused by closeNotifyTimeout when using SslHandler
Motivation:

In the SslHandler we schedule a timeout at which we close the Channel if a timeout was detected during close_notify. Because this can race with notify the flushFuture we can see an IllegalStateException when the Channel is closed.

Modifications:

- Use a trySuccess() and tryFailure(...) to guard against race.

Result:

No more race.
2015-05-06 21:50:16 +02:00
yz_liu
488d905598 fix a typo in RecyclableArrayList 2015-05-06 09:07:48 +02:00
Norman Maurer
cf66edb3a1 [#3675] Fix livelock issue in MpscLinkedQueue
Motivation:

All read operations should be safe to execute from multiple threads which was not the case and so could produce a livelock.

Modifications:

Modify methods so these are safe to be called from multiple threads.

Result:

No more livelock.
2015-05-06 06:21:14 +02:00
Trustin Lee
63a02fc04e Revamp DNS codec
Motivation:

There are various known issues in netty-codec-dns:

- Message types are not interfaces, which can make it difficult for a
  user to implement his/her own message implementation.
- Some class names and field names do not match with the terms in the
  RFC.
- The support for decoding a DNS record was limited. A user had to
  encode and decode by him/herself.
- The separation of DnsHeader from DnsMessage was unnecessary, although
  it is fine conceptually.
- Buffer leak caused by DnsMessage was difficult to analyze, because the
  leak detector tracks down the underlying ByteBuf rather than the
  DnsMessage itself.
- DnsMessage assumes DNS-over-UDP.
- To send an EDNS message, a user have to create a new DNS record class
  instance unnecessarily.

Modifications:

- Make all message types interfaces and add default implementations
- Rename some classes, properties, and constants to match the RFCs
  - DnsResource -> DnsRecord
  - DnsType -> DnsRecordType
  - and many more
- Remove DnsClass and use an integer to support EDNS better
- Add DnsRecordEncoder/DnsRecordDecoder and their default
  implementations
  - DnsRecord does not require RDATA to be ByteBuf anymore.
  - Add DnsRawRecord as the catch-all record type
- Merge DnsHeader into DnsMessage
- Make ResourceLeakDetector track AbstractDnsMessage
- Remove DnsMessage.sender/recipient properties
  - Wrap DnsMessage with AddressedEnvelope
  - Add DatagramDnsQuest and DatagramDnsResponse for ease of use
  - Rename DnsQueryEncoder to DatagramDnsQueryEncoder
  - Rename DnsResponseDecoder to DatagramDnsResponseDecoder
- Miscellaneous changes
  - Add StringUtil.TAB

Result:

- Cleaner APi
- Can support DNS-over-TCP more easily in the future
- Reduced memory footprint in the default DnsQuery/Response
  implementations
- Better leak tracking for DnsMessages
- Possibility to introduce new DnsRecord types in the future and provide
  full record encoder/decoder implementation.
- No unnecessary instantiation for an EDNS pseudo resource record
2015-05-01 11:33:16 +09:00
JongYoon Lim
a5c8e145ee Remove the condition which is always true when reached
Motivation:
Condition 'isNextCharDoubleQuote' is always 'true' when reached.

Motification:
- Removed Condition 'isNextCharDoubleQuote'.
- Additionally fixed typo in javadoc

Result:
Cleaner code.
2015-04-30 16:58:39 -07:00
Norman Maurer
56c98839c3 [#3218] Add ChannelPool / ChannelPoolMap abstraction and implementations
Motivation:

Many projects need some kind a Channel/Connection pool implementation. While the protocols are different many things can be shared, so we should provide a generic API and implementation.

Modifications:

Add ChannelPool / ChannelPoolMap API and implementations.

Result:

Reusable / Generic pool implementation that users can use.
2015-04-30 12:13:19 +02:00
JongYoon Lim
05f9593352 Remove the unreachable checking code
Motivation:
'length2 == 0' is not reachable because length1 and length2 are same at this point.

Motification:
Removed 'length2 == 0'.

Result:
Cleaner code.
2015-04-30 07:43:26 +02:00
JongYoon Lim
c4d69e982b Remove duplicate code in ConstantPool class
Motivation:

Currently, valueOf() and newInstance() use almost same code to create new constant.
For maintainability, it's better to share duplicate code among them.

Motification:

Added new private functions.
- checkNotNullAndNotEmpty() is for checking whether the name of a constant is null and empty.
- newConstant0() is for creating a new constant.

Result:

- Compact source code
- Improvement of maintainability
2015-04-29 08:03:37 +02:00
Norman Maurer
f67b14bf35 [#3680] Enabled SecurityManager results in ClassNotFoundError during io.netty.util.NetUtil initialization
Motivation:

When a SecurityManager is in place that preven reading the somaxconn file trying to bootstrap a channel later will result in a ClassNotFoundError.

Modifications:

- Reading the file in a privileged block.

Result:

No more ClassNotFoundError when a SecurityManager is in place.
2015-04-27 20:02:07 +02:00
Scott Mitchell
f812180c2d ByteString arrayOffset method
Motivation:
The ByteString class currently assumes the underlying array will be a complete representation of data. This is limiting as it does not allow a subsection of another array to be used. The forces copy operations to take place to compensate for the lack of API support.

Modifications:
- add arrayOffset method to ByteString
- modify all ByteString and AsciiString methods that loop over or index into the underlying array to use this offset
- update all code that uses ByteString.array to ensure it accounts for the offset
- add unit tests to test the implementation respects the offset

Result:
ByteString and AsciiString can represent a sub region of a byte[].
2015-04-24 18:54:01 -07:00
Norman Maurer
a7d1dc362a [#3652] Improve performance of StringUtil.simpleClassName()
Motivation:

static Package getPackage(Class<?> c) uses synchronized block internally.
Thanks to @jingene for the hint and initial report of the issue.

Modifications:

-Use simple lastIndexOf(...) and substring for a faster implementation

Result:

No more lock condition.
2015-04-22 09:14:40 +02:00
Norman Maurer
b4b14ea19f Ensure backward-compability with 4.0
Motivation:

Each different *ChannelOption did extend ChannelOption in 4.0, which we changed in 4.1. This is a breaking change in terms of the API so we need to ensure we keep the old hierarchy.

Modifications:

- Let all *ChannelOption extend ChannelOption
- Add back constructor and mark it as @deprecated

Result:

No API breakage between 4.0 and 4.1
2015-04-19 13:25:42 +02:00
Trustin Lee
e48e6e4509 Fix checkstyle 2015-04-17 11:39:36 +09:00
Jakob Buchgraber
c2de195f87 Improve performance of AsciiString.equals(Object).
Motivation:

The current implementation does byte by byte comparison, which we have seen
can be a performance bottleneck when the AsciiString is used as the key in
a Map.

Modifications:

Use sun.misc.Unsafe (on supporting platforms) to compare up to eight bytes at a time
and get closer to the performance of String.equals(Object).

Result:

Significant improvement (2x - 6x) in performance over the current implementation.

Benchmark                                             (size)   Mode   Samples        Score  Score error    Units
i.n.m.i.PlatformDependentBenchmark.arraysBytesEqual       10  thrpt        10 118843477.518 2347259.347    ops/s
i.n.m.i.PlatformDependentBenchmark.arraysBytesEqual       50  thrpt        10 43910319.773   198376.996    ops/s
i.n.m.i.PlatformDependentBenchmark.arraysBytesEqual      100  thrpt        10 26339969.001   159599.252    ops/s
i.n.m.i.PlatformDependentBenchmark.arraysBytesEqual     1000  thrpt        10  2873119.030    20779.056    ops/s
i.n.m.i.PlatformDependentBenchmark.arraysBytesEqual    10000  thrpt        10   306370.450     1933.303    ops/s
i.n.m.i.PlatformDependentBenchmark.arraysBytesEqual   100000  thrpt        10    25750.415      108.391    ops/s
i.n.m.i.PlatformDependentBenchmark.unsafeBytesEqual       10  thrpt        10 248077563.510  635320.093    ops/s
i.n.m.i.PlatformDependentBenchmark.unsafeBytesEqual       50  thrpt        10 128198943.138  614827.548    ops/s
i.n.m.i.PlatformDependentBenchmark.unsafeBytesEqual      100  thrpt        10 86195621.349  1063959.307    ops/s
i.n.m.i.PlatformDependentBenchmark.unsafeBytesEqual     1000  thrpt        10 16920264.598    61615.365    ops/s
i.n.m.i.PlatformDependentBenchmark.unsafeBytesEqual    10000  thrpt        10  1687454.747     6367.602    ops/s
i.n.m.i.PlatformDependentBenchmark.unsafeBytesEqual   100000  thrpt        10   153717.851      586.916    ops/s
2015-04-16 17:29:54 -07:00
Roger Kapsi
221a9f50d4 Fix for ByteString#hashCode()
Motivation:

ByteString#hashCode() trashes its own hash code if it's being accessed concurrently

Modifications:

Pull the ByteString#hash into a local variable and calculate it locally.

Result:

ByteString#hashCode() is no longer returning a junk value.
2015-04-16 17:00:44 -07:00
nmittler
7aac50a79a Optimizing KObjectHashMap hashIndex()
Motivation:

The IntObjectHashMap benchmarks show the Agrona collections to be faster on put, lookup, and remove. One major difference is that we're using 2 modulus operations each time we increment the position index while iterating.  Agrona uses a mask instead.

Modifications:

Modified the KObjectHashMap to use masking rather than modulus when wrapping the position index. This requires that the capacity be a power of 2.

Result:

Improved performance of IntObjectHashMap.
2015-04-16 10:27:17 -07:00
Scott Mitchell
9a7a85dbe5 ByteString introduced as AsciiString super class
Motivation:
The usage and code within AsciiString has exceeded the original design scope for this class. Its usage as a binary string is confusing and on the verge of violating interface assumptions in some spots.

Modifications:
- ByteString will be created as a base class to AsciiString. All of the generic byte handling processing will live in ByteString and all the special character encoding will live in AsciiString.

Results:
The AsciiString interface will be clarified. Users of AsciiString can now be clear of the limitations the class imposes while users of the ByteString class don't have to live with those limitations.
2015-04-14 16:35:17 -07:00
Norman Maurer
0d9ba81c06 Document the contract of Attribute.getAndSet(...) and set(...)
Motivation:

Attribute.getAndRemove() will return the value but also remove the AttributeKey itself from the AttributeMap. This may not
what you want as you may want to keep an instance of it and just set it later again. Document the contract so the user know what to expect.

Modifications:

- Make it clear when to use AttributeKey.getAndRemove() / AttributeKey.remove() and when AttributeKey.getAndSet(null) / AttributeKey.set(null).

Result:

Less suprising behaviour.
2015-04-14 09:53:53 +02:00
Norman Maurer
aebbb862ac Add support for ALPN when using openssl + NPN client mode and support for CipherSuiteFilter
Motivation:

To support HTTP2 we need APLN support. This was not provided before when using OpenSslEngine, so SSLEngine (JDK one) was the only bet.
Beside this CipherSuiteFilter was not supported

Modifications:

- Upgrade netty-tcnative and make use of new features to support ALPN and NPN in server and client mode.
- Guard against segfaults after the ssl pointer is freed
- support correctly different failure behaviours
- add support for CipherSuiteFilter

Result:

Be able to use OpenSslEngine for ALPN / NPN for server and client.
2015-04-10 18:52:34 +02:00
nmittler
3354296c9f Auto-generating primitive collections for int and char keys.
Motivation:

Currently we have IntObjectMap/HashMap, but it will be useful to support other primitive-based maps.

Modifications:

Moved the code int the current maps to template files and run Groovy code from  common/pom.xml to apply the templates.

Result:

Autogeneration of int and char-based hash maps.
2015-04-10 07:57:30 -07:00
Jakob Buchgraber
e40c27d9ed Avoid object allocations for HTTP2 child streams.
Motivation:

We are allocating a hash map for every HTTP2 Stream to store it's children.
Most streams are leafs in the priority tree and don't have children.

Modification:

 - Only allocate children when we actually use them.
 - Make EmptyIntObjectMap not throw a UnsupportedOperationException on remove, but return null instead (as is stated in it's javadoc).

Result:

Fewer unnecessary allocations.
2015-04-03 11:57:31 -07:00
Scott Mitchell
330bc39d91 Backporting PrimitiveCollections class
Motivation:
PrimitiveCollections is not in the 4.1 branch.  It is needed by HTTP/2.

Modifications:
Backport this class.

Result:
PrimitiveCollections is in 4.1.
2015-04-03 11:57:09 -07:00
nmittler
ef729e7021 Allow non-standard HTTP/2 settings
Motivation:

The Http2Settings class currently disallows setting non-standard settings, which violates the spec.

Modifications:

Updated Http2Settings to permit arbitrary settings. Also adjusting the default initial capacity to allow setting all of the standard settings without reallocation.

Result:

Fixes #3560
2015-04-02 11:10:47 -07:00
Norman Maurer
3df7b4dac7 Respect -Djava.net.preferIPv4Stack when using epoll transport
Motivation:

On a system where ipv4 and ipv6 are supported a user may want to use -Djava.net.preferIPv4Stack=true to restrict it to use ipv4 only.
This is currently ignored with the epoll transport.

Modifications:

Respect java.net.preferIPv4Stack system property.

Result:

-Djava.net.preferIPv4Stack=true will have the effect the user is looking for.
2015-03-11 02:50:11 +01:00
Norman Maurer
0767da12fb Fix possible AttributeMap corruption on double removal
Motivation:

When remove0() is called multiple times for an DefaultAttribute it can cause corruption of the internal linked-list structure.

Modifications:

- Ensure remove0() can not cause corruption by null out prev and next references.

Result:

No more corruption possible
2015-03-10 05:08:41 +01:00
Norman Maurer
fce0989844 [maven-release-plugin] prepare for next development iteration 2015-03-03 02:06:47 -05:00
Norman Maurer
ca3b1bc4b7 [maven-release-plugin] prepare release netty-4.1.0.Beta4 2015-03-03 02:05:52 -05:00
Norman Maurer
a709553819 Allow to use EmbeddedChannel.schedule*(...)
Motivation:

At the moment when EmbeddedChannel is used and a ChannelHandler tries to schedule and task it will throw an UnsupportedOperationException. This makes it impossible to test these handlers or even reuse them with EmbeddedChannel.

Modifications:

- Factor out reusable scheduling code into AbstractSchedulingEventExecutor
- Let EmbeddedEventLoop and SingleThreadEventExecutor extend AbstractSchedulingEventExecutor
- add EmbbededChannel.runScheduledPendingTasks() which allows to run all scheduled tasks that are ready

Result:

Embeddedchannel is now usable even with ChannelHandler that try to schedule tasks.
2015-02-20 11:57:32 +01:00
Daniel Bevenius
c53b8d5a85 Suggestion for supporting single header fields.
Motivation:
At the moment if you want to return a HTTP header containing multiple
values you have to set/add that header once with the values wanted. If
you used set/add with an array/iterable multiple HTTP header fields will
be returned in the response.

Note, that this is indeed a suggestion and additional work and tests
should be added. This is mainly to bring up a discussion.

Modifications:
Added a flag to specify that when multiple values exist for a single
HTTP header then add them as a comma separated string.
In addition added a method to StringUtil to help escape comma separated
value charsequences.

Result:
Allows for responses to be smaller.
2015-02-18 10:54:15 +01:00