BasicTokenIterator Class Reference

Basic implementation of a com.good.gd.apache.http.TokenIterator. More...

Inheritance diagram for BasicTokenIterator:

Description

This implementation parses token sequences as defined by RFC 2616, section 2. It extends that definition somewhat beyond US-ASCII.

Version

Revision

602520

Notice

The following notice applies to the original API on which this API is based, and to its documentation. The documentation of this API has been revised from the original.

/*
 * Copyright (C) 2006 The Android Open Source Project
 *
 * 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.
 */

Public Member Functions
	BasicTokenIterator (final HeaderIterator headerIterator)
	Creates a new instance of BasicTokenIterator. More...
boolean	hasNext ()
	Indicates whether there is another token in this iteration. More...
String	nextToken () throws NoSuchElementException, ParseException
	Obtains the next token from this iteration. More...
final Object	next () throws NoSuchElementException, ParseException
	Returns the next token. More...
final void	remove () throws UnsupportedOperationException
	Removing tokens is not supported. More...

Static Public Attributes
static final String	HTTP_SEPARATORS = " ,;=()<>@:\\\"/[]?{}\t"
	The HTTP separator characters. More...

Protected Member Functions
int	findNext (int from) throws ParseException
	Determines the next token. More...
String	createToken (String value, int start, int end)
	Creates a new token to be returned. More...
int	findTokenStart (int from)
	Determines the starting position of the next token. More...
int	findTokenSeparator (int from)
	Determines the position of the next token separator. More...
int	findTokenEnd (int from)
	Determines the ending position of the current token. More...
boolean	isTokenSeparator (char ch)
	Checks whether a character is a token separator. More...
boolean	isWhitespace (char ch)
	Checks whether a character is a whitespace character. More...
boolean	isTokenChar (char ch)
	Checks whether a character is a valid token character. More...
boolean	isHttpSeparator (char ch)
	Checks whether a character is an HTTP separator. More...

Protected Attributes
final HeaderIterator	headerIt
	The iterator from which to obtain the next header. More...
String	currentHeader
	The value of the current header. More...
String	currentToken
	The token to be returned by the next call to currentToken. More...
int	searchPos
	The position after currentToken in currentHeader. More...

Constructor & Destructor Documentation

BasicTokenIterator()

BasicTokenIterator

(

final HeaderIterator

headerIterator

)

Parameters

headerIterator

the iterator for the headers to tokenize

Member Function Documentation

hasNext()

boolean hasNext

(

)

Returns

true if there is another token, false otherwise

Implements TokenIterator.

nextToken()

String nextToken

(

)

throws NoSuchElementException, ParseException

Returns

the next token in this iteration

Exceptions

NoSuchElementException	if the iteration is already over
ParseException	if an invalid header value is encountered

Implements TokenIterator.

next()

final Object next

(

)

throws NoSuchElementException, ParseException

Same as nextToken, but with generic return type.

Returns

the next token in this iteration

Exceptions

NoSuchElementException	if there are no more tokens
ParseException	if an invalid header value is encountered

remove()

final void remove

(

)

throws UnsupportedOperationException

Exceptions

UnsupportedOperationException

always

findNext()

int findNext ( int  from ) throws ParseException

protected

If found, the token is stored in currentToken. The return value indicates the position after the token in currentHeader. If necessary, the next header will be obtained from headerIt. If not found, currentToken is set to null.

Parameters

from	the position in the current header at which to start the search, -1 to search in the first header

Returns

the position after the found token in the current header, or negative if there was no next token

Exceptions

ParseException

if an invalid header value is encountered

createToken()

String createToken ( String  value, int  start, int  end  )

protected

Called from findNext after the token is identified. The default implementation simply calls java.lang.String.substring.
If header values are significantly longer than tokens, and some tokens are permanently referenced by the application, there can be problems with garbage collection. A substring will hold a reference to the full characters of the original string and therefore occupies more memory than might be expected. To avoid this, override this method and create a new string instead of a substring.

Parameters

value	the full header value from which to create a token
start	the index of the first token character
end	the index after the last token character

Returns

a string representing the token identified by the arguments

findTokenStart()

int findTokenStart ( int  from )

protected

This method will iterate over headers if necessary.

Parameters

from	the position in the current header at which to start the search

Returns

the position of the token start in the current header, negative if no token start could be found

findTokenSeparator()

int findTokenSeparator ( int  from )

protected

Because of multi-header joining rules, the end of a header value is a token separator. This method does therefore not need to iterate over headers.

Parameters

from	the position in the current header at which to start the search

Returns

the position of a token separator in the current header, or at the end

Exceptions

ParseException

if a new token is found before a token separator. RFC 2616, section 2.1 explicitly requires a comma between tokens for #.

findTokenEnd()

int findTokenEnd ( int  from )

protected

This method will not leave the current header value, since the end of the header value is a token boundary.

Parameters

from	the position of the first character of the token

Returns

the position after the last character of the token. The behavior is undefined if from does not point to a token character in the current header value.

isTokenSeparator()

boolean isTokenSeparator ( char  ch )

protected

RFC 2616, section 2.1 defines comma as the separator for token sequences. The end of a header value will also separate tokens, but that is not a character check.

Parameters

ch	the character to check

Returns

true if the character is a token separator, false otherwise

isWhitespace()

boolean isWhitespace ( char  ch )

protected

RFC 2616, section 2.2 defines space and horizontal tab as whitespace. The optional preceeding line break is irrelevant, since header continuation is handled transparently when parsing messages.

Parameters

ch	the character to check

Returns

true if the character is whitespace, false otherwise

isTokenChar()

boolean isTokenChar ( char  ch )

protected

Whitespace, control characters, and HTTP separators are not valid token characters. The HTTP specification (RFC 2616, section 2.2) defines tokens only for the US-ASCII character set, this method extends the definition to other character sets.

Parameters

ch	the character to check

Returns

true if the character is a valid token start, false otherwise

isHttpSeparator()

boolean isHttpSeparator ( char  ch )

protected

The implementation in this class checks only for the HTTP separators defined in RFC 2616, section 2.2. If you need to detect other separators beyond the US-ASCII character set, override this method.

Parameters

ch	the character to check

Returns

true if the character is an HTTP separator

Member Data Documentation

HTTP_SEPARATORS

final String HTTP_SEPARATORS = " ,;=()<>@:\\\"/[]?{}\t"

static

Defined in RFC 2616, section 2.2.

headerIt

final HeaderIterator headerIt

protected

currentHeader

String currentHeader

protected

This is the header value that includes currentToken. Undefined if the iteration is over.

currentToken

String currentToken

protected

null if the iteration is over.

searchPos

int searchPos

protected

Undefined if the iteration is over.