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

public class IpHashBaseUrlRetrieveStrategy implements BaseUrlRetrieveStrategy {
    private final String[] urls;

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

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

    private int getHashCode(String ip) {
        final int prime = 31;
        int result = 1;
        int ipHashcode = 0;
        if (ip != null) {
            ipHashcode = ip.hashCode();
        }
        result = prime * result + ipHashcode;
        return result;
    }

}