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012// ***************************************************************************************************************************
013package org.apache.juneau.http;
014
015/**
016 * Represents a parsed <l>Content-Location</l> HTTP response header.
017 * 
018 * <p>
019 * An alternate location for the returned data.
020 * 
021 * <h5 class='figure'>Example</h5>
022 * <p class='bcode'>
023 *    Content-Location: /index.htm
024 * </p>
025 * 
026 * <h5 class='topic'>RFC2616 Specification</h5>
027 * 
028 * The Content-Location entity-header field MAY be used to supply the resource location for the entity enclosed in the
029 * message when that entity is accessible from a location separate from the requested resource's URI.
030 * A server SHOULD provide a Content-Location for the variant corresponding to the response entity; especially in the
031 * case where a resource has multiple entities associated with it, and those entities actually have separate locations
032 * by which they might be individually accessed, the server SHOULD provide a Content-Location for the particular variant
033 * which is returned.
034 * <p class='bcode'>
035 *    Content-Location = "Content-Location" ":"
036 *                       ( absoluteURI | relativeURI )
037 * </p>
038 * 
039 * <p>
040 * The value of Content-Location also defines the base URI for the entity.
041 * 
042 * <p>
043 * The Content-Location value is not a replacement for the original requested URI; it is only a statement of the
044 * location of the resource corresponding to this particular entity at the time of the request.
045 * Future requests MAY specify the Content-Location URI as the request- URI if the desire is to identify the source of
046 * that particular entity.
047 * 
048 * <p>
049 * A cache cannot assume that an entity with a Content-Location different from the URI used to retrieve it can be used
050 * to respond to later requests on that Content-Location URI.
051 * However, the Content- Location can be used to differentiate between multiple entities retrieved from a single
052 * requested resource, as described in section 13.6.
053 * 
054 * <p>
055 * If the Content-Location is a relative URI, the relative URI is interpreted relative to the Request-URI.
056 * 
057 * <p>
058 * The meaning of the Content-Location header in PUT or POST requests is undefined; servers are free to ignore it in
059 * those cases.
060 * 
061 * <h5 class='section'>See Also:</h5>
062 * <ul class='doctree'>
063 *    <li class='extlink'><a class='doclink' href='https://www.w3.org/Protocols/rfc2616/rfc2616.html'>Hypertext Transfer Protocol -- HTTP/1.1</a>
064 * </ul>
065 */
066public final class ContentLocation extends HeaderUri {
067
068   /**
069    * Returns a parsed <code>Content-Location</code> header.
070    * 
071    * @param value The <code>Content-Location</code> header string.
072    * @return The parsed <code>Content-Location</code> header, or <jk>null</jk> if the string was null.
073    */
074   public static ContentLocation forString(String value) {
075      if (value == null)
076         return null;
077      return new ContentLocation(value);
078   }
079
080   private ContentLocation(String value) {
081      super(value);
082   }
083}