org.forgerock.http.header

Class HeaderUtil

java.lang.Object

org.forgerock.http.header.HeaderUtil

public final class HeaderUtil
extends Object

Utility class for processing values in HTTP header fields.

Method Summary

Modifier and Type	Method and Description
static String	formatDate(Date date) Formats a HTTP-date using RFC 1123 format as specified in RFC 2616.
static String	join(Collection<String> values, char separator) Joins a collection of header values into a single header value, with a specified specified separator.
static Date	parseDate(String s) Parses the supported HTTP-date formats as specified in RFC 2616.
static List<String>	parseMultiValuedHeader(Message message, String name) Parses the named header from the message as a multi-valued comma separated value.
static List<String>	parseMultiValuedHeader(String header) Parses the header content as a multi-valued comma separated value.
static String[]	parseParameter(String value) Splits a single HTTP header parameter name and value from an input string value.
static Map<String,String>	parseParameters(Collection<String> values) Parses a set of HTTP header parameters from a collection of values.
static String	parseSingleValuedHeader(Message message, String name) Parses the named single-valued header from the message.
static String	quote(String value) Encloses a string in quotation marks.
static List<String>	split(String value, char separator) Parses an HTTP header value, splitting it into multiple values around the specified separator.
static String	unquote(String value) Unquotes a string following the logic of quote(String).

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

split

public static List<String> split(String value,
                                 char separator)

Parses an HTTP header value, splitting it into multiple values around the specified separator. Quoted strings are not split into multiple values if they contain separator characters. All leading and trailing white space in values is trimmed. All quotations remain intact.

Note: This method is liberal in its interpretation of malformed header values; namely the incorrect use of string and character quoting mechanisms and unquoted white space. If a null or empty string is supplied as a value, this method yields an empty list.

Parameters:

value - the header value to be split.

separator - the separator character to split headers around.

Returns:

A list of string representing the split values of the header.

join

public static String join(Collection<String> values,
                          char separator)

Joins a collection of header values into a single header value, with a specified specified separator. A null or empty collection of header values yeilds a null return value.

Parameters:

values - the values to be joined.

separator - the separator to separate values within the returned value.

Returns:

a single header value, with values separated by the separator.

parseParameter

public static String[] parseParameter(String value)

Splits a single HTTP header parameter name and value from an input string value. The input string value is presumed to have been extracted from a collection provided by the split(String, char) method.

This method returns the parameter name-value pair split into an array of Strings. Element [0] contains the parameter name; element [1] contains contains the parameter value or null if there is no value.

A value that is contained within a quoted-string is processed such that the surrounding '"' (quotation mark) characters are removed and single-character quotations hold the character being quoted without the escape '\' (backslash) character. All white space outside of the quoted-string is removed. White space within the quoted-string is retained.

Note: This method is liberal in its interpretation of a malformed header value; namely the incorrect use of string and character quoting mechanisms and unquoted white space.

Parameters:

value - the string to parse the name-value parameter from.

Returns:

the name-value pair split into a String array.

parseParameters

public static Map<String,String> parseParameters(Collection<String> values)

Parses a set of HTTP header parameters from a collection of values. The input collection of values is presumed to have been provided from the split(String, char) method.

A well-formed parameter contains an attribute and optional value, separated by an '=' (equals sign) character. If the parameter contains no value, it is represented by a null value in the returned map.

Values that are contained in quoted-strings are processed such that the surrounding '"' (quotation mark) characters are removed and single-character quotations hold the character being quoted without the escape '\' (backslash) character. All white space outside of quoted-strings is removed. White space within quoted-strings is retained.

Note: This method is liberal in its interpretation of malformed header values; namely the incorrect use of string and character quoting mechanisms and unquoted white space.

Parameters:

values - the HTTP header parameters.

Returns:

a map of parameter name-value pairs.

quote

public static String quote(String value)

Encloses a string in quotation marks. Quotation marks and backslash characters are escaped with the single-character quoting mechanism. For more information, see RFC 2616 §2.2.

Parameters:

value - the value to be enclosed in quotation marks.

Returns:

the value enclosed in quotation marks.

unquote

public static String unquote(String value)

Unquotes a string following the logic of quote(String).

Parameters:

value - Value to unquote

Returns:

Unquoted value

parseMultiValuedHeader

public static List<String> parseMultiValuedHeader(Message message,
                                                  String name)

Parses the named header from the message as a multi-valued comma separated value. If there are multiple headers present then they are first merged and then split.

Parameters:

message - The HTTP request or response.

name - The name of the header.

Returns:

A list of strings representing the split values of the header, which may be empty if the header was not present in the message.

parseMultiValuedHeader

public static List<String> parseMultiValuedHeader(String header)

Parses the header content as a multi-valued comma separated value.

Parameters:

header - The HTTP header content.

Returns:

A list of strings representing the split values of the header, which may be empty if the header was null or empty.

parseSingleValuedHeader

public static String parseSingleValuedHeader(Message message,
                                             String name)

Parses the named single-valued header from the message. If there are multiple headers present then only the first is used.

Parameters:

message - The HTTP request or response.

name - The name of the header.

Returns:

The header value, or null if the header was not present in the message.

formatDate

public static String formatDate(Date date)

Formats a HTTP-date using RFC 1123 format as specified in RFC 2616.

Parameters:

date - Date to format

Returns:

Formatted HTTP-date

parseDate

public static Date parseDate(String s)

Parses the supported HTTP-date formats as specified in RFC 2616.

Parameters:

s - Date String

Returns:

Date instance, or null if unable to parse the date or s is null