RoundRobinBaseUrlRetrieveStrategy.java

/* 
 * Licensed 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.esigate.url;

import java.util.concurrent.atomic.AtomicInteger;

import org.esigate.api.BaseUrlRetrieveStrategy;
import org.esigate.http.IncomingRequest;

public class RoundRobinBaseUrlRetrieveStrategy implements BaseUrlRetrieveStrategy {
    private final AtomicInteger counter = new AtomicInteger(0);
    private final String[] urls;

    public RoundRobinBaseUrlRetrieveStrategy(String[] urls) {
        this.urls = urls;
    }

    @Override
    public String getBaseURL(IncomingRequest originalRequest) {
        int incremented = this.counter.incrementAndGet();
        int index = incremented % this.urls.length;
        return this.urls[Math.abs(index)];
    }
}