/*

  * 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.johnzon.core;

 import java.io.Serializable;

 public abstract class ThreadLocalBufferCache<T> implements Serializable {

     // alloc are expensive so using a very trivial buffer, we remove from TL to say we use it and reset it when we are done (close)

     private final ThreadLocal<T> buffers;

     private final int defaultSize;

     public ThreadLocalBufferCache(final int defaultSize) {

         this.buffers = new ThreadLocal<T>() {

             @Override

             protected T initialValue() {

                 return ThreadLocalBufferCache.this.newValue(defaultSize);

             }

         };

         this.defaultSize = defaultSize;

     }

     protected abstract T newValue(final int defaultSize);

     public T getCache() {

         final T cachedLoadedChars = buffers.get();

         if (cachedLoadedChars == null) {

             return newValue(defaultSize);

         }

         buffers.set(null); // remove just kills the buffers

         return cachedLoadedChars;

     }

     public void release(final T buffer) {

         buffers.set(buffer);

     }

 }