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# HTTPResource

The basic class of all resources accessible through the HTTP protocol. As a webadmin, you shouldn't try to install an instance of an HTTPResource, since it doesn't provide any implementation of the actual HTTP methods.

## Inherits

The HTTPResource class inherits from the following classes:

- Resource

## Attributes description

The HTTPResource defines the following attributes:

- parent
- url
- server
- quality
- title
- content-language
- content-encoding
- content-type
- content-length
- last-modified
- expires
- icon
- maxage

`parent`

semantics
  The parent of a resource is the resource that is responsible for its loading in memory. All resources should have a parent, except for the server's root resource (whose parent is null)
type
  This attribute is a computed ObjectAttribute
default value
  This attribute defaults to the resource that loaded it into memory, as explained above.

`url`

semantics
  The location of this resource within the server that exports it. This is given as a string, parseable into a Java URL.
type
  This attribute is a computed StringAttribute
default value
  This attribute defaults to the concatenation of the resource's parent `url` attribute with its own name (or identifier).

`server`

semantics
  The server that makes this resource accessible through HTTP.
type
  This attribute is a computed ObjectAttribute
default value
  This attribute defaults to its parent's `server` attribute value.

`quality`

semantics
  A rating of the quality of this resource's content. The rating is provided as a number between 0.0 and 1.0. It is used mainly by the NegotiatedResource to negotiate among its set of variants.
type
  This attribute is an editable DoubleAttribute.
default value
  This attribute defaults to 1.0.

`title`

semantics
  The title of this resource. This attribute can be either computed from the resource content (e.g. if the content is an HTML file which has some `META` tag), or provided for informational purposes (even if the resource's content type is not `text/html`.)
type
  This attribute is a computed and/or editable StringAttribute.
default value
  This attribute is undefined by default.

`content-language`

semantics
  The natural language of the resource content. This is used mainly by the NegotiatedResource to negotiate among its set of variant resources. The value of this attribute can be either extracted from the resource content (e.g. if it is an `HTML` file that includes some appropriate META tag), or provided for informational purposes.
type
  This attribute is a computed and/or editable LanguageAttribute.
default value
  This attribute is undefined by default.

`content-encoding`

semantics
  The encoding in which the resource's contenht is stored. Right now this can only be a single token (as described in the HTTP/1.0 specification).
type
  This attribute is a computed and/or editable EncodingAttribute.
default value
  This attribute is undefined by default.

`content-type`

semantics
  The (MIME) type of the resource's content.
type
  This attribute is a computed and/or editable MimeTypeAttribute.
default value
  This attribute is undefined by default.

`content-length`

semantics
  The length of the resource's content.
type
  This attribute is a computed IntegerAttribute.
default value
  This attribute is undefined by default. It is up to sub-classes of resources to either generate it dynamically, or cache it from its sources (e.g.the FileResource caches this information that it gets through file system calls).

`last-modified`

semantics
  The date of the last modification of this resource.
type
  This attribute is a computed and/or editable DateAttribute.
default value
  This attribute is undefined by default, it is up to sub-classes of resources to either generate it dynamically, or cache it from its sources (as above).

`expires`

semantics
  The date at which this resource expires.
type
  This attribute is a computed and/or editable DateAttribute.
default value
  This attribute is undefined by default, it is up to sub-classes of resources to either generate it dynamically, or cache it from its sources (as above).

`icon`

semantics
  Any icon to be associated with the resource. This is used, for example, to produce nice directory listings.
type
  This attribute is an editable StringAttribute
default value
  This attribute is undefined by default.

`maxage`

semantics
  This attribute defines the allowed drift between the real content of a resource, and the one that is sent as request replies. The bigger this value, the more efficient the server can be, since it will be able to reuse cachd request replies for a longer time. This attribute takes effect only if it is defined, and if the resource provides a meaningfull `last-modified` attribute value.
type
  This attribute is an editable IntegerAttribute
default value
  This attribute is undefined by default.

Jigsaw Team
$Id: w3c.jigsaw.resources.HTTPResource.html,v 1.1 1996/04/11 20:05:11 abaird Exp $