81 lines
3.4 KiB
Java
81 lines
3.4 KiB
Java
/*
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* The MIT License
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* Copyright © 2014-2021 Ilkka Seppälä
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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package com.iluwatar.object.pool;
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import org.slf4j.Logger;
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import org.slf4j.LoggerFactory;
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/**
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* When it is necessary to work with a large number of objects that are particularly expensive to
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* instantiate and each object is only needed for a short period of time, the performance of an
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* entire application may be adversely affected. An object pool design pattern may be deemed
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* desirable in cases such as these.
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*
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* <p>The object pool design pattern creates a set of objects that may be reused. When a new object
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* is needed, it is requested from the pool. If a previously prepared object is available it is
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* returned immediately, avoiding the instantiation cost. If no objects are present in the pool, a
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* new item is created and returned. When the object has been used and is no longer needed, it is
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* returned to the pool, allowing it to be used again in the future without repeating the
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* computationally expensive instantiation process. It is important to note that once an object has
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* been used and returned, existing references will become invalid.
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*
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* <p>In this example we have created {@link OliphauntPool} inheriting from generic {@link
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* ObjectPool}. {@link Oliphaunt}s can be checked out from the pool and later returned to it. The
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* pool tracks created instances and their status (available, inUse).
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*/
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public class App {
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private static final Logger LOGGER = LoggerFactory.getLogger(App.class);
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/**
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* Program entry point.
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*
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* @param args command line args
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*/
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public static void main(String[] args) {
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var pool = new OliphauntPool();
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LOGGER.info(pool.toString());
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var oliphaunt1 = pool.checkOut();
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String checkedOut = "Checked out {}";
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LOGGER.info(checkedOut, oliphaunt1);
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LOGGER.info(pool.toString());
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var oliphaunt2 = pool.checkOut();
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LOGGER.info(checkedOut, oliphaunt2);
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var oliphaunt3 = pool.checkOut();
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LOGGER.info(checkedOut, oliphaunt3);
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LOGGER.info(pool.toString());
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LOGGER.info("Checking in {}", oliphaunt1);
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pool.checkIn(oliphaunt1);
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LOGGER.info("Checking in {}", oliphaunt2);
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pool.checkIn(oliphaunt2);
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LOGGER.info(pool.toString());
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var oliphaunt4 = pool.checkOut();
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LOGGER.info(checkedOut, oliphaunt4);
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var oliphaunt5 = pool.checkOut();
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LOGGER.info(checkedOut, oliphaunt5);
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LOGGER.info(pool.toString());
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}
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}
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