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package org.apache.juneau.jsonschema.annotation;

import static java.lang.annotation.RetentionPolicy.*;

import java.lang.annotation.*;

/**
 * Swagger external documentation annotation.
 *
 * <p>
 * Allows referencing an external resource for extended documentation.
 *
 * <p>
 * Used to populate the auto-generated Swagger documentation and UI for server-side <ja>@RestResource</ja>-annotated classes.
 *
 * <h5 class='section'>Examples:</h5>
 * <p class='bcode w800'>
 *    <jc>// Normal</jc>
 *    <ja>@RestResource</ja>(
 *       swagger=<ja>@ResourceSwagger</ja>(
 *          externalDocs=<ja>@ExternalDocs</ja>(
 *             description=<js>"Apache Juneau"</js>,
 *             url=<js>"http://juneau.apache.org"</js>
 *          )
 *       )
 *    )
 * </p>
 * <p class='bcode w800'>
 *    <jc>// Free-form</jc>
 *    <ja>@RestResource</ja>(
 *       swagger=<ja>@ResourceSwagger</ja>(
 *          contact=<ja>@ExternalDocs</ja>({
 *             <js>"description:'Apache Juneau',"</js>,
 *             <js>"url:'http://juneau.apache.org'"</js>,
 *          })
 *       )
 *    )
 * </p>
 *
 * <h5 class='section'>See Also:</h5>
 * <ul>
 *    <li class='link'>{@doc juneau-rest-server.Swagger}
 *    <li class='extlink'>{@doc SwaggerExternalDocumentationObject}
 * </ul>
 */
@Documented
@Retention(RUNTIME)
public @interface ExternalDocs {

   /**
    * <mk>description</mk> field of the {@doc SwaggerExternalDocumentationObject}.
    *
    * <p>
    * A short description of the target documentation.
    *
    * <h5 class='section'>Notes:</h5>
    * <ul class='spaced-list'>
    *    <li>
    *       The format is a plain-text string.
    *       <br>Multiple lines are concatenated with newlines.
    *    <li>
    *       Supports {@doc DefaultRestSvlVariables}
    *       (e.g. <js>"$L{my.localized.variable}"</js>).
    * </ul>
    */
   String[] description() default {};

   /**
    * <mk>url</mk> field of the {@doc SwaggerExternalDocumentationObject}.
    *
    * <p>
    * The URL for the target documentation. Value MUST be in the format of a URL.
    *
    * <h5 class='section'>Notes:</h5>
    * <ul class='spaced-list'>
    *    <li>
    *       The value is required.
    *    <li>
    *       The format is a URL string.
    *    <li>
    *       Supports {@doc DefaultRestSvlVariables}
    *       (e.g. <js>"$L{my.localized.variable}"</js>).
    * </ul>
    */
   String url() default "";

   /**
    * Free-form value for the {@doc SwaggerExternalDocumentationObject}.
    *
    * <p>
    * This is a {@doc juneau-marshall.JsonDetails.SimplifiedJson} object that makes up the swagger information for this field.
    *
    * <p>
    * The following are completely equivalent ways of defining the swagger description of documentation:
    * <p class='bcode w800'>
    *    <jc>// Normal</jc>
    *    <ja>@RestResource</ja>(
    *       swagger=<ja>@ResourceSwagger</ja>(
    *          externalDocs=<ja>@ExternalDocs</ja>(
    *             description=<js>"Find out more about Juneau"</js>,
    *             url=<js>"http://juneau.apache.org"</js>
    *          )
    *       )
    *    )
    * </p>
    * <p class='bcode w800'>
    *    <jc>// Free-form</jc>
    *    <ja>@RestResource</ja>(
    *       swagger=<ja>@ResourceSwagger</ja>(
    *          externalDocs=<ja>@ExternalDocs</ja>({
    *             <js>"description: 'Find out more about Juneau',"</js>,
    *             <js>"url: 'http://juneau.apache.org'"</js>
    *          })
    *       )
    *    )
    * </p>
    * <p class='bcode w800'>
    *    <jc>// Free-form with variables</jc>
    *    <ja>@RestResource</ja>(
    *       swagger=<ja>@ResourceSwagger</ja>(
    *          externalDocs=<ja>@ExternalDocs</ja>(<js>"$L{externalDocsSwagger}"</js>)
    *       )
    *    )
    * </p>
    * <p class='bcode w800'>
    *    <mc>// Contents of MyResource.properties</mc>
    *    <mk>externalDocsSwagger</mk> = <mv>{ description: "Find out more about Juneau", url: "http://juneau.apache.org" }</mv>
    * </p>
    *
    * <p>
    *    The reasons why you may want to use this field include:
    * <ul>
    *    <li>You want to pull in the entire Swagger JSON definition for this field from an external source such as a properties file.
    *    <li>You want to add extra fields to the Swagger documentation that are not officially part of the Swagger specification.
    * </ul>
    *
    * <h5 class='section'>Notes:</h5>
    * <ul class='spaced-list'>
    *    <li>
    *       The format is a {@doc juneau-marshall.JsonDetails.SimplifiedJson} object.
    *    <li>
    *       The leading/trailing <code>{ }</code> characters are optional.
    *       <br>The following two example are considered equivalent:
    *       <p class='bcode w800'>
    *    <ja>@ExternalDocs</ja>(<js>"{url:'http://juneau.apache.org'}"</js>)
    *       </p>
    *       <p class='bcode w800'>
    *    <ja>@ExternalDocs</ja>(<js>"url:'http://juneau.apache.org'"</js>)
    *       </p>
    *    <li>
    *       Multiple lines are concatenated with newlines so that you can format the value to be readable.
    *    <li>
    *       Supports {@doc DefaultRestSvlVariables}
    *       (e.g. <js>"$L{my.localized.variable}"</js>).
    *    <li>
    *       Values defined in this field supersede values pulled from the Swagger JSON file and are superseded by individual values defined on this annotation.
    * </ul>
    */
   String[] value() default {};
}