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/*
 * The MIT License
 * Copyright (c) 2012 Microsoft Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

package microsoft.exchange.webservices.data.core;

/**
 * Wrapper class for lazy members. Does lazy initialization of member on first
 * access.
 *
 * @param  Type of the lazy member
 *            

* If we find ourselves creating a whole bunch of these in our code, * we need to rethink this. Each lazy member holds the actual member * and a delegate. That can turn into a whole lot of overhead *

*/ public class LazyMember { /** * The lazy member. */ private volatile T lazyMember; /** * The lazy implementation. */ private final ILazyMember lazyImplementation; /** * Public accessor for the lazy member. Lazy initializes the member on first * access * * @return the member */ public T getMember() { T result = this.lazyMember; if (result == null) { // first check (no locking) synchronized (this) { result = this.lazyMember; if (result == null) { // second check (with locking) this.lazyMember = result = lazyImplementation.createInstance(); } } } return result; } /** * Constructor. * * @param lazyImplementation The initialization delegate to call for the item on first * access */ public LazyMember(ILazyMember lazyImplementation) { this.lazyImplementation = lazyImplementation; } }




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