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/*
 * DISCLAIMER
 *
 * Copyright 2017 ArangoDB GmbH, Cologne, Germany
 *
 * 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.
 *
 * Copyright holder is ArangoDB GmbH, Cologne, Germany
 */

package com.arangodb.internal.net;

import java.util.ArrayList;
import java.util.Collections;

import com.arangodb.internal.Host;

/**
 * @author Mark Vollmary
 *
 */
public class RandomHostHandler implements HostHandler {

	private final HostResolver resolver;
	private final HostHandler fallback;
	private Host origin;
	private Host current;

	public RandomHostHandler(final HostResolver resolver, final HostHandler fallback) {
		super();
		this.resolver = resolver;
		this.fallback = fallback;
		origin = current = getRandomHost(true, false);
	}

	@Override
	public Host get() {
		if (current == null) {
			origin = current = getRandomHost(false, true);
		}
		return current;
	}

	@Override
	public void success() {
		current = origin;
	}

	@Override
	public void fail() {
		fallback.fail();
		current = fallback.get();
	}

	private Host getRandomHost(final boolean initial, final boolean closeConnections) {
		final ArrayList hosts = new ArrayList(resolver.resolve(initial, closeConnections));
		Collections.shuffle(hosts);
		return hosts.get(0);
	}

}