netty5/common/src/main/java/io/netty/util/internal/UnpaddedInternalThreadLocalMap.java
Xiaoyan Lin b7415a3307 Add a reusable ArrayList to InternalThreadLocalMap
Motivation:

See #3411. A reusable ArrayList in InternalThreadLocalMap can avoid allocations in the following pattern:

```
List<...> list = new ArrayList<...>();

add something to list but never use InternalThreadLocalMap

return list.toArray(new ...[list.size()]);

```

Modifications:

Add a reusable ArrayList to InternalThreadLocalMap and update codes to use it.

Result:

Reuse a thread local ArrayList to avoid allocations.
2016-02-01 15:49:28 +01:00

62 lines
2.1 KiB
Java

/*
* Copyright 2014 The Netty Project
*
* The Netty Project licenses this file to you under the Apache License,
* version 2.0 (the "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
package io.netty.util.internal;
import io.netty.util.concurrent.FastThreadLocal;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import java.nio.charset.CharsetEncoder;
import java.util.ArrayList;
import java.util.Map;
import java.util.concurrent.atomic.AtomicInteger;
/**
* The internal data structure that stores the thread-local variables for Netty and all {@link FastThreadLocal}s.
* Note that this class is for internal use only and is subject to change at any time. Use {@link FastThreadLocal}
* unless you know what you are doing.
*/
class UnpaddedInternalThreadLocalMap {
static ThreadLocal<InternalThreadLocalMap> slowThreadLocalMap;
static final AtomicInteger nextIndex = new AtomicInteger();
/** Used by {@link FastThreadLocal} */
Object[] indexedVariables;
// Core thread-locals
int futureListenerStackDepth;
int localChannelReaderStackDepth;
Map<Class<?>, Boolean> handlerSharableCache;
IntegerHolder counterHashCode;
ThreadLocalRandom random;
Map<Class<?>, TypeParameterMatcher> typeParameterMatcherGetCache;
Map<Class<?>, Map<String, TypeParameterMatcher>> typeParameterMatcherFindCache;
// String-related thread-locals
StringBuilder stringBuilder;
Map<Charset, CharsetEncoder> charsetEncoderCache;
Map<Charset, CharsetDecoder> charsetDecoderCache;
// ArrayList-related thread-locals
ArrayList<Object> arrayList;
UnpaddedInternalThreadLocalMap(Object[] indexedVariables) {
this.indexedVariables = indexedVariables;
}
}