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// *  http://www.apache.org/licenses/LICENSE-2.0                                                                             *
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package org.apache.juneau.http.header;

import java.util.function.*;

import org.apache.juneau.annotation.*;
import org.apache.juneau.http.annotation.*;

/**
 * Represents a parsed <l>Content-Encoding</l> HTTP response header.
 *
 * <p>
 * The type of encoding used on the data.
 *
 * <h5 class='figure'>Example</h5>
 * <p class='bcode'>
 *    Content-Encoding: gzip
 * </p>
 *
 * <h5 class='topic'>RFC2616 Specification</h5>
 *
 * The Content-Encoding entity-header field is used as a modifier to the media-type.
 * When present, its value indicates what additional content codings have been applied to the entity-body, and thus
 * what decoding mechanisms must be applied in order to obtain the media-type referenced by the Content-Type header
 * field.
 * Content-Encoding is primarily used to allow a document to be compressed without losing the identity of its
 * underlying media type.
 * <p class='bcode'>
 *    Content-Encoding  = "Content-Encoding" ":" 1#content-coding
 * </p>
 *
 * <p>
 * Content codings are defined in section 3.5. An example of its use is...
 * <p class='bcode'>
 *    Content-Encoding: gzip
 * </p>
 *
 * <p>
 * The content-coding is a characteristic of the entity identified by the Request-URI.
 * Typically, the entity-body is stored with this encoding and is only decoded before rendering or analogous usage.
 * However, a non-transparent proxy MAY modify the content-coding if the new coding is known to be acceptable to the
 * recipient, unless the "no-transform" cache-control directive is present in the message.
 *
 * <p>
 * If the content-coding of an entity is not "identity", then the response MUST include a Content-Encoding
 * entity-header (section 14.11) that lists the non-identity content-coding(s) used.
 *
 * <p>
 * If the content-coding of an entity in a request message is not acceptable to the origin server, the server SHOULD
 * respond with a status code of 415 (Unsupported Media Type).
 *
 * <p>
 * If multiple encodings have been applied to an entity, the content codings MUST be listed in the order in which they
 * were applied.
 * Additional information about the encoding parameters MAY be provided.
 *
 * <h5 class='section'>See Also:</h5><ul>
 *    <li class='link'><a class="doclink" href="../../../../../index.html#juneau-rest-common">juneau-rest-common</a>
 *    <li class='extlink'><a class="doclink" href="https://www.w3.org/Protocols/rfc2616/rfc2616.html">Hypertext Transfer Protocol -- HTTP/1.1</a>
 * </ul>
 *
 * @serial exclude
 */
@Header("Content-Encoding")
@Schema(_enum={"gzip","compress","deflate","identity","other"})
public class ContentEncoding extends BasicStringHeader {

   //-----------------------------------------------------------------------------------------------------------------
   // Static
   //-----------------------------------------------------------------------------------------------------------------

   private static final long serialVersionUID = 1L;
   private static final String NAME = "Content-Encoding";

   /**
    * Static creator.
    *
    * @param value
    *    The header value.
    *    <br>Can be <jk>null</jk>.
    * @return A new header bean, or <jk>null</jk> if the value is <jk>null</jk>.
    */
   public static ContentEncoding of(String value) {
      return value == null ? null : new ContentEncoding(value);
   }

   /**
    * Static creator with delayed value.
    *
    * <p>
    * Header value is re-evaluated on each call to {@link #getValue()}.
    *
    * @param value
    *    The supplier of the header value.
    *    <br>Can be <jk>null</jk>.
    * @return A new header bean, or <jk>null</jk> if the value is <jk>null</jk>.
    */
   public static ContentEncoding of(Supplier<String> value) {
      return value == null ? null : new ContentEncoding(value);
   }

   //-----------------------------------------------------------------------------------------------------------------
   // Instance
   //-----------------------------------------------------------------------------------------------------------------

   /**
    * Constructor.
    *
    * @param value
    *    The header value.
    *    <br>Can be <jk>null</jk>.
    */
   public ContentEncoding(String value) {
      super(NAME, value);
   }

   /**
    * Constructor with delayed value.
    *
    * <p>
    * Header value is re-evaluated on each call to {@link #getValue()}.
    *
    * @param value
    *    The supplier of the header value.
    *    <br>Can be <jk>null</jk>.
    */
   public ContentEncoding(Supplier<String> value) {
      super(NAME, value);
   }
}