content: /*
   * 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.activemq.artemis.utils.pools;
  
  import java.util.Queue;
  import java.util.function.Consumer;
  import java.util.function.Supplier;
  
  /**
   * A simple encapsulation to provide a pool of objects.
   */
  public abstract class Pool<T> {
  
     private final Queue<T> internalPool;
  
     private final Consumer<T> cleaner;
     private final Supplier<T> supplier;
  
     public Pool(int maxSize, Consumer<T> cleaner, Supplier<T> supplier) {
        internalPool = createQueue(maxSize);
        this.cleaner = cleaner;
        this.supplier = supplier;
     }
  
     abstract Queue<T> createQueue(int maxSize);
  
     /**
      * Use this to instantiate or return objects from the pool
      */
     public final T borrow() {
        if (internalPool == null) {
           return supplier.get();
        }
  
        T returnObject = internalPool.poll();
  
        if (returnObject == null) {
           returnObject = supplier.get();
        } else {
           cleaner.accept(returnObject);
        }
  
        return returnObject;
     }
  
     /**
      * Return objects to the pool, they will be either reused or ignored by the max size
      */
     public final void release(T object) {
        if (internalPool != null) {
           internalPool.offer(object);
        }
     }
  }
  