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/**
 * Copyright (C) 2009-2011 Couchbase, Inc.
 *
 * 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 DEALING
 * IN THE SOFTWARE.
 */

package net.spy.memcached;

import java.util.HashMap;
import java.util.Map;

/**
 * Registry of known hashing algorithms for locating a server for a key. Useful
 * when configuring from files using algorithm names.
 *
 * 

* Please, make sure you register your algorithm with { * {@link #registerHashAlgorithm(String, HashAlgorithm)} before referring to it * by name */ public final class HashAlgorithmRegistry { private HashAlgorithmRegistry() { // Empty } /** * Internal registry storage. */ private static final Map REGISTRY = new HashMap(); // initializing with the default algorithms implementation static { for (DefaultHashAlgorithm alg : DefaultHashAlgorithm.values()) { registerHashAlgorithm(alg.name().replace("_HASH", "").toLowerCase(), alg); } } /** * Registers provided {@link HashAlgorithm} instance with the given name. Name * is not case sensitive. Any registered algorithm with the same name will be * substituted * * @param name name of the algorithm * @param alg algorithm instance to register */ public static synchronized void registerHashAlgorithm(String name, HashAlgorithm alg) { validateName(name); validateAlgorithm(alg); REGISTRY.put(name.toLowerCase(), alg); } /** * Tries to find selected hash algorithm using name provided. * *

* Note, that lookup is being performed using name's lower-case value * * @param name the algorithm name to be used for lookup * @return a {@link HashAlgorithm} instance or null if there's no * algorithm with the specified name */ public static synchronized HashAlgorithm lookupHashAlgorithm(String name) { validateName(name); return REGISTRY.get(name.toLowerCase()); } /** * Validates name of the algorithm. A non-empty name should be provided An * {@link IllegalArgumentException} is being thrown in case of incorrect name * * @param name a name to validate */ private static void validateName(String name) { if (name == null || "".equals(name)) { throw new IllegalArgumentException("HashAlgorithm name should be" + "provided in order to perform the lookup: either NULL or " + "empty string has been provided"); } } /** * Validates algorithm instance. A non-null instance should be * provided. An {@link IllegalArgumentException} is being thrown in case of * null instance * * @param alg a {@link HashAlgorithm} instance to validate */ private static void validateAlgorithm(HashAlgorithm alg) { if (alg == null) { throw new IllegalArgumentException("HashAlgorithm instance should be " + "provided in order to register a new algorithm"); } } }





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