Host.java

/*******************************************************************************
 * Copyright 2011 Netflix
 * 
 * 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 com.netflix.dyno.connectionpool;

import java.net.InetSocketAddress;

import com.netflix.dyno.connectionpool.impl.utils.ConfigUtils;

/**
 * Class encapsulating information about a host.
 *
 * This is immutable except for the host status.
 * Note that the HostSupplier may not know the Dynomite port,
 * whereas the Host object created by the load balancer
 * may receive the port the cluster_describe REST call.
 * Hence, we must not use the port in the equality and hashCode
 * calculations.
 *
 * @author poberai
 * @author ipapapanagiotou
 *
 */
public class Host implements Comparable<Host> {

    public static final int DEFAULT_PORT = 8102;
    public static final Host NO_HOST = new Host("UNKNOWN", "UNKNOWN", 0, "UNKNOWN");

    private final String hostname;
    private final String ipAddress;
    private final int port;
    private final InetSocketAddress socketAddress;
    private final String rack;
    private final String datacenter;
    private Status status = Status.Down;

    public enum Status {
        Up, Down;
    }

    public Host(String hostname, int port, String rack) {
        this(hostname, null, port, rack, ConfigUtils.getDataCenterFromRack(rack), Status.Down);
    }

    public Host(String hostname, String rack, Status status) {
        this(hostname, null, DEFAULT_PORT, rack, ConfigUtils.getDataCenterFromRack(rack), status);
    }

    public Host(String hostname, int port, String rack, Status status) {
        this(hostname, null, port, rack, ConfigUtils.getDataCenterFromRack(rack), status);
    }

    public Host(String hostname, String ipAddress, int port, String rack) {
        this(hostname, ipAddress, port, rack, ConfigUtils.getDataCenterFromRack(rack), Status.Down);
    }

    public Host(String hostname, String ipAddress, String rack, Status status) {
        this(hostname, ipAddress, DEFAULT_PORT, rack, ConfigUtils.getDataCenterFromRack(rack), status);
    }

    public Host(String name, String ipAddress, int port, String rack, String datacenter, Status status) {
        this.hostname = name;
        this.ipAddress = ipAddress;
        this.port = port;
        this.rack = rack;
        this.status = status;
        this.datacenter = datacenter;

        // Used for the unit tests to prevent host name resolution
        if (port != -1) {
            this.socketAddress = new InetSocketAddress(name, port);
        } else {
            this.socketAddress = null;
        }
    }

    public String getHostAddress() {
        if (this.ipAddress != null) {
            return ipAddress;
        }
        return hostname;
    }

    public String getHostName() {
        return hostname;
    }

    public String getIpAddress() {
        return ipAddress;
    }

    public int getPort() {
        return port;
    }

    public String getDatacenter() {
        return datacenter;
    }

    public String getRack() {
        return rack;
    }

    public Host setStatus(Status condition) {
        status = condition;
        return this;
    }

    public boolean isUp() {
        return status == Status.Up;
    }

    public InetSocketAddress getSocketAddress() {
        return socketAddress;
    }

    /**
     * Equality checks will fail in collections between Host objects
     * created from the HostSupplier, which may not know the Dynomite port, and
     * the Host objects created by the load balancer.
     */
    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((hostname == null) ? 0 : hostname.hashCode());
        result = prime * result + ((rack == null) ? 0 : rack.hashCode());

        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;

        if (getClass() != obj.getClass())
            return false;

        Host other = (Host) obj;
        boolean equals = true;

        equals &= (hostname != null) ? hostname.equals(other.hostname) : other.hostname == null;
        equals &= (rack != null) ? rack.equals(other.rack) : other.rack == null;

        return equals;
    }

    @Override
    public int compareTo(Host o) {
        int compared = this.hostname.compareTo(o.hostname);
        if (compared != 0) {
            return compared;
        }
        return this.rack.compareTo(o.rack);
    }

    @Override
    public String toString() {
        return "Host [hostname=" + hostname + ", ipAddress=" + ipAddress + ", port=" + port + ", rack: " + rack
                + ", datacenter: " + datacenter + ", status: " + status.name() + "]";
    }
}