software.amazon.awssdk.regions.RegionScope Maven / Gradle / Ivy

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/*
 * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License").
 * You may not use this file except in compliance with the License.
 * A copy of the License is located at
 *
 *  http://aws.amazon.com/apache2.0
 *
 * or in the "license" file accompanying this file. 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 software.amazon.awssdk.regions;

import java.util.Arrays;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import software.amazon.awssdk.annotations.SdkPublicApi;
import software.amazon.awssdk.utils.Validate;

/**
 * This class represents the concept of a regional scope, in form of a string with possible wildcards.
 * 
 * The string can contain a region value such as us-east-1, or add the wildcard '*' at the end of the region
 * string to represent all possible regional combinations that can match the expression. A wildcard must be
 * it's own segment and preceeded by a '-' dash, unless the whole expression is the wildcard.
 * 

 * Examples of valid combinations:
 * 

 *     'us-east-1' - Represents the region exactly
 *     'eu-west-*' - Represents all regions that start with 'eu-west-'
 *     'eu-*' - Represents all regions that start with 'eu-'
 *     '*' - Represents all regions, i.e. a global scope
 * 
 * 
 * Examples of invalid combinations:
 * 

 *     'us-*-1' - The wildcard must appear at the end.
 *     'eu-we*' - The wildcard must be its own segment
 * 
 */
@SdkPublicApi
public final class RegionScope {

    public static final RegionScope GLOBAL;

    private static final Pattern REGION_SCOPE_PATTERN;

    //Pattern must be compiled when static scope is created
    static {
        REGION_SCOPE_PATTERN = Pattern.compile("^([a-z0-9-])*([*]?)$");
        GLOBAL = RegionScope.create("*");
    }

    private final String regionScope;

    private RegionScope(String regionScope) {
        this.regionScope = Validate.paramNotBlank(regionScope, "regionScope");
        validateFormat(regionScope);
    }

    /**
     * Gets the string representation of this region scope.
     */
    public String id() {
        return this.regionScope;
    }

    /**
     * Creates a RegionScope with the supplied value.
     *
     * @param value See class documentation {@link RegionScope} for allowed values.
     */
    public static RegionScope create(String value) {
        return new RegionScope(value);
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }

        RegionScope that = (RegionScope) o;

        return regionScope.equals(that.regionScope);
    }

    @Override
    public int hashCode() {
        return 31 * (1 + (regionScope != null ? regionScope.hashCode() : 0));
    }

    private void validateFormat(String regionScope) {
        Matcher matcher = REGION_SCOPE_PATTERN.matcher(regionScope);
        if (!matcher.matches()) {
            if (regionScope.contains(",")) {
                throw new IllegalArgumentException("Incorrect region scope '" + regionScope + "'. Region scopes with more than "
                                                   + "one region defined are not supported.");
            }
            throw new IllegalArgumentException("Incorrect region scope '" + regionScope + "'. Region scope must be a"
                                               + " string that either is a complete region string, such as 'us-east-1',"
                                               + " or uses the wildcard '*' to represent any region that starts with"
                                               + " the preceding parts. Wildcards must appear as a separate segment after"
                                               + " a '-' dash, for example 'us-east-*'. A global scope of '*' is allowed.");
        }
        List segments = Arrays.asList(regionScope.split("-"));
        String lastSegment = segments.get(segments.size() - 1);
        if (lastSegment.contains("*") && lastSegment.length() != 1) {
            throw new IllegalArgumentException("Incorrect region scope '" + regionScope
                                               + "'. A wildcard must only appear on its own at the end of the expression "
                                               + "after a '-' dash. A global scope of '*' is allowed.");
        }
    }
}