Class MimeHeaders


public class MimeHeaders extends Object
Memory-efficient repository for Mime Headers. When the object is recycled, it will keep the allocated headers[] and all the MimeHeaderField - no GC is generated.

For input headers it is possible to use the MessageByte for Fields - so no GC will be generated.

The only garbage is generated when using the String for header names/values - this can't be avoided when the servlet calls header methods, but is easy to avoid inside tomcat. The goal is to use _only_ MessageByte-based Fields, and reduce to 0 the memory overhead of tomcat.

This class is used to contain standard internet message headers, used for SMTP (RFC822) and HTTP (RFC2068) messages as well as for MIME (RFC 2045) applications such as transferring typed data and grouping related items in multipart message bodies.

Message headers, as specified in RFC822, include a field name and a field body. Order has no semantic significance, and several fields with the same name may exist. However, most fields do not (and should not) exist more than once in a header.

Many kinds of field body must conform to a specified syntax, including the standard parenthesized comment syntax. This class supports only two simple syntaxes, for dates and integers.

When processing headers, care must be taken to handle the case of multiple same-name fields correctly. The values of such fields are only available as strings. They may be accessed by index (treating the header as an array of fields), or by name (returning an array of string values).

Headers are first parsed and stored in the order they are received. This is based on the fact that most servlets will not directly access all headers, and most headers are single-valued. (the alternative - a hash or similar data structure - will add an overhead that is not needed in most cases)

Apache seems to be using a similar method for storing and manipulating headers.

Author:, James Todd [], Costin Manolache, kevin seguin