pool

SimpleConnection.java

package com.aemobile.pool;

/**
 * Created by winry on 2019/7/19.
 */
public class SimpleConnection implements Connection {

	private String server;

	public SimpleConnection(String server) {
		this.server = server;
	}

	public String getServer() {
		return server;
	}

	@Override
	public boolean isConnectionLost() {
		return false;
	}
}

SimpleConnectionPool.java

package org.winry;

import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

/**
 * Created by winry on 2019/7/19.
 */
public class SimpleConnectionPool implements ConnectionPool {

	private List<Connection> connections = new ArrayList<>();
	private final Random rand = new Random();

	public SimpleConnectionPool(String[] servers, int perServerConnectionCount) {
		for (String server : servers) {
			for (int i = 0; i < perServerConnectionCount; i++) {
				Connection connection = new SimpleConnection(server);
				connections.add(connection);
			}
		}
		ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1);
		scheduler.scheduleAtFixedRate(new Runnable() {
			@Override
			public void run() {
				updateConnections();
			}
		}, 30, 30, TimeUnit.SECONDS);
	}

	@Override
	public Connection getConnection() {
		if (connections.isEmpty()) return null;

		int index = rand.nextInt(connections.size());

		for (int i = 0; i < connections.size(); i++) {
			Connection connection = connections.get(index);
			if (!connection.isConnectionLost()) {
				return connection;
			} else {
				index++;
				if (index >= connections.size()) index = 0;
			}
		}

		return null;
	}

	private void updateConnections() {
		boolean update = false;
		List<Connection> nweConnections = new ArrayList<>(connections);

		for (int i = 0; i < connections.size(); i++) {
			Connection connection = nweConnections.get(i);
			if (connection.isConnectionLost()) {
				Connection newConnection = new SimpleConnection(((SimpleConnection) connection).getServer());
				nweConnections.set(i, newConnection);
				update = true;
			}
		}

		if (update) {
			connections = nweConnections;
		}
	}

}