/*
* RequestHeader.java February 2001
*
* Copyright (C) 2001, Niall Gallagher <niallg@users.sf.net>
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
* implied. See the License for the specific language governing
* permissions and limitations under the License.
*/
package org.simpleframework.http;
import java.util.List;
import java.util.Locale;
/**
* This is a <code>Header</code> object that is used to represent a
* basic form for the HTTP request message. This is used to extract
* values such as the request line and header values from the request
* message. Access to header values is done case insensitively.
* <p>
* As well as providing the header values and request line values
* this will also provide convenience methods which enable the user
* to determine the length of the body this message header prefixes.
*
* @author Niall Gallagher
*/
public interface RequestHeader extends RequestLine {
/**
* This method is used to get a <code>List</code> of the names
* for the headers. This will provide the original names for the
* HTTP headers for the message. Modifications to the provided
* list will not affect the header, the list is a simple copy.
*
* @return this returns a list of the names within the header
*/
List<String> getNames();
/**
* This can be used to get the integer of the first message header
* that has the specified name. This is a convenience method that
* avoids having to deal with parsing the value of the requested
* HTTP message header. This returns -1 if theres no HTTP header
* value for the specified name.
*
* @param name the HTTP message header to get the value from
*
* @return this returns the date as a long from the header value
*/
int getInteger(String name);
/**
* This can be used to get the date of the first message header
* that has the specified name. This is a convenience method that
* avoids having to deal with parsing the value of the requested
* HTTP message header. This returns -1 if theres no HTTP header
* value for the specified name.
*
* @param name the HTTP message header to get the value from
*
* @return this returns the date as a long from the header value
*/
long getDate(String name);
/**
* This is used to acquire a cookie using the name of that cookie.
* If the cookie exists within the HTTP header then it is returned
* as a <code>Cookie</code> object. Otherwise this method will
* return null. Each cookie object will contain the name, value
* and path of the cookie as well as the optional domain part.
*
* @param name this is the name of the cookie object to acquire
*
* @return this returns a cookie object from the header or null
*/
Cookie getCookie(String name);
/**
* This is used to acquire all cookies that were sent in the header.
* If any cookies exists within the HTTP header they are returned
* as <code>Cookie</code> objects. Otherwise this method will an
* empty list. Each cookie object will contain the name, value and
* path of the cookie as well as the optional domain part.
*
* @return this returns all cookie objects from the HTTP header
*/
List<Cookie> getCookies();
/**
* This can be used to get the value of the first message header
* that has the specified name. The value provided from this will
* be trimmed so there is no need to modify the value, also if
* the header name specified refers to a comma separated list of
* values the value returned is the first value in that list.
* This returns null if theres no HTTP message header.
*
* @param name the HTTP message header to get the value from
*
* @return this returns the value that the HTTP message header
*/
String getValue(String name);
/**
* This can be used to get the value of the first message header
* that has the specified name. The value provided from this will
* be trimmed so there is no need to modify the value, also if
* the header name specified refers to a comma separated list of
* values the value returned is the first value in that list.
* This returns null if theres no HTTP message header.
*
* @param name the HTTP message header to get the value from
* @param index if there are multiple values this selects one
*
* @return this returns the value that the HTTP message header
*/
String getValue(String name, int index);
/**
* This can be used to get the values of HTTP message headers
* that have the specified name. This is a convenience method that
* will present that values as tokens extracted from the header.
* This has obvious performance benefits as it avoids having to
* deal with <code>substring</code> and <code>trim</code> calls.
* <p>
* The tokens returned by this method are ordered according to
* there HTTP quality values, or "q" values, see RFC 2616 section
* 3.9. This also strips out the quality parameter from tokens
* returned. So "image/html; q=0.9" results in "image/html". If
* there are no "q" values present then order is by appearance.
* <p>
* The result from this is either the trimmed header value, that
* is, the header value with no leading or trailing whitespace
* or an array of trimmed tokens ordered with the most preferred
* in the lower indexes, so index 0 is has highest preference.
*
* @param name the name of the headers that are to be retrieved
*
* @return ordered array of tokens extracted from the header(s)
*/
List<String> getValues(String name);
/**
* This is used to acquire the locales from the request header. The
* locales are provided in the <code>Accept-Language</code> header.
* This provides an indication as to the languages that the client
* accepts. It provides the locales in preference order.
*
* @return this returns the locales preferred by the client
*/
List<Locale> getLocales();
/**
* This is a convenience method that can be used to determine the
* content type of the message body. This will determine whether
* there is a <code>Content-Type</code> header, if there is then
* this will parse that header and represent it as a typed object
* which will expose the various parts of the HTTP header.
*
* @return this returns the content type value if it exists
*/
ContentType getContentType();
/**
* This is a convenience method that can be used to determine
* the length of the message body. This will determine if there
* is a <code>Content-Length</code> header, if it does then the
* length can be determined, if not then this returns -1.
*
* @return the content length, or -1 if it cannot be determined
*/
long getContentLength();
/**
* This method returns a <code>CharSequence</code> holding the header
* consumed for the request. A character sequence is returned as it
* can provide a much more efficient means of representing the header
* data by just wrapping the consumed byte array.
*
* @return this returns the characters consumed for the header
*/
CharSequence getHeader();
/**
* This method returns a string representing the header that was
* consumed for this request. For performance reasons it is better
* to acquire the character sequence representing the header as it
* does not require the allocation on new memory.
*
* @return this returns a string representation of this request
*/
String toString();
}