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EMC Atmos Client for Java - provides REST access to object data on EMC platforms using the Atmos API.

There is a newer version: 3.2.1

/*
 * Copyright (c) 2013-2016, EMC Corporation.
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * + Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 * + Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * + The name of EMC Corporation may not be used to endorse or promote
 *   products derived from this software without specific prior written
 *   permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
package com.emc.atmos;

import java.net.URI;

/**
 * This implementation will tie a specific endpoint to each thread to avoid MDS sync issues. However, multiple threads
 * will be distributed between the configured endpoints.
 */
public class StickyThreadAlgorithm implements LoadBalancingAlgorithm {
    protected ThreadLocal threadEndpoint = new ThreadLocal();
    protected int callCount = 0;

    @Override
    public URI getNextEndpoint( URI[] endpoints ) {
        // tie the endpoint to the current thread to eliminate MDS sync issues when using multiple endpoints
        URI endpoint = threadEndpoint.get();
        if ( endpoint == null ) {
            endpoint = endpoints[callCount++ % endpoints.length];
            threadEndpoint.set( endpoint );
        }
        return endpoint;
    }
}