| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF 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 org.apache.geode.internal.serialization; |
| |
| import java.lang.ref.SoftReference; |
| |
| /** |
| * Provides a simple thread local cache of a single byte array. |
| */ |
| class ThreadLocalByteArrayCache { |
| private final ThreadLocal<SoftReference<byte[]>> cache = new ThreadLocal<>(); |
| private final int maximumArraySize; |
| |
| /** |
| * @param maximumArraySize byte arrays larger than this size will not be cached |
| */ |
| public ThreadLocalByteArrayCache(int maximumArraySize) { |
| this.maximumArraySize = maximumArraySize; |
| } |
| |
| /** |
| * Returns a byte array whose length it at least minimumLength. |
| * NOTE: the same thread can not safely call this method again |
| * until it has finished using the byte array returned by a previous call. |
| * If minimumLength is larger than this cache's maximumArraySize |
| * then the returned byte array will not be cached. |
| * |
| * @param minimumLength the minimum length of the byte array |
| * @return a byte array, owned by this thread, whose length is at least minimumLength. |
| */ |
| public byte[] get(int minimumLength) { |
| SoftReference<byte[]> reference = cache.get(); |
| byte[] result = (reference != null) ? reference.get() : null; |
| if (result == null || result.length < minimumLength) { |
| result = new byte[minimumLength]; |
| if (minimumLength <= maximumArraySize) { |
| cache.set(new SoftReference<byte[]>(result)); |
| } |
| } |
| return result; |
| } |
| } |