Regions.java

/*
 * Copyright 2013-2017 Amazon Technologies, Inc.
 *
 * 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://aws.amazon.com/apache2.0
 *
 * This file 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.amazonaws.regions;

import com.amazonaws.AmazonClientException;
import org.apache.commons.logging.LogFactory;

import com.amazonaws.SdkClientException;
import com.amazonaws.util.EC2MetadataUtils;

/**
 * Enumeration of region names
 */
public enum Regions {

    GovCloud("us-gov-west-1"),
    US_EAST_1("us-east-1"),
    US_EAST_2("us-east-2"),
    US_WEST_1("us-west-1"),
    US_WEST_2("us-west-2"),
    EU_WEST_1("eu-west-1"),
    EU_WEST_2("eu-west-2"),
    EU_CENTRAL_1("eu-central-1"),
    AP_SOUTH_1("ap-south-1"),
    AP_SOUTHEAST_1("ap-southeast-1"),
    AP_SOUTHEAST_2("ap-southeast-2"),
    AP_NORTHEAST_1("ap-northeast-1"),
    AP_NORTHEAST_2("ap-northeast-2"),
    SA_EAST_1("sa-east-1"),
    CN_NORTH_1("cn-north-1"),
    CA_CENTRAL_1("ca-central-1")
    ;

    /**
     * The default region that new customers in the US are encouraged to use
     * when using AWS services for the first time.
     */
    public static final Regions DEFAULT_REGION = US_WEST_2;

    private final String name;

    private Regions(String name) {
        this.name = name;
    }

    /**
     * The name of this region, used in the regions.xml file to identify it.
     */
    public String getName() {
        return name;
    }

    /**
     * Returns a region enum corresponding to the given region name.
     *
     * @param regionName
     *            The name of the region. Ex.: eu-west-1
     * @return Region enum representing the given region name.
     */
    public static Regions fromName(String regionName) {
        for (Regions region : Regions.values()) {
            if (region.getName().equals(regionName)) {
                return region;
            }
        }
        throw new IllegalArgumentException("Cannot create enum from " + regionName + " value!");
    }

    /**
     * Returns a Region object representing the region the application is
     * running in, when running in EC2. If this method is called from a non-EC2
     * environment, it will return null.
     */
    public static Region getCurrentRegion() {
        try {
            final String region = EC2MetadataUtils.getEC2InstanceRegion();
            if (region != null)
                return RegionUtils.getRegion(region);
        } catch (AmazonClientException e) {
            LogFactory.getLog(Regions.class).debug(
                "Ignoring failure to retrieve the region: " + e.getMessage());
        }
        return null;
    }
}