Package org.apache.http.message
Class BasicTokenIterator
java.lang.Object
org.apache.http.message.BasicTokenIterator
- All Implemented Interfaces:
Iterator<Object>
,TokenIterator
Basic implementation of a
TokenIterator
.
This implementation parses #token
sequences as
defined by RFC 2616, section 2.
It extends that definition somewhat beyond US-ASCII.- Since:
- 4.0
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Field Summary
FieldsModifier and TypeFieldDescriptionprotected String
The value of the current header.protected String
The token to be returned by the next call tonextToken()
.protected final HeaderIterator
The iterator from which to obtain the next header.static final String
The HTTP separator characters.protected int
The position aftercurrentToken
incurrentHeader
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Constructor Summary
ConstructorsConstructorDescriptionBasicTokenIterator
(HeaderIterator headerIterator) Creates a new instance ofBasicTokenIterator
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Method Summary
Modifier and TypeMethodDescriptionprotected String
createToken
(String value, int start, int end) Creates a new token to be returned.protected int
findNext
(int pos) Determines the next token.protected int
findTokenEnd
(int from) Determines the ending position of the current token.protected int
findTokenSeparator
(int pos) Determines the position of the next token separator.protected int
findTokenStart
(int pos) Determines the starting position of the next token.boolean
hasNext()
Indicates whether there is another token in this iteration.protected boolean
isHttpSeparator
(char ch) Checks whether a character is an HTTP separator.protected boolean
isTokenChar
(char ch) Checks whether a character is a valid token character.protected boolean
isTokenSeparator
(char ch) Checks whether a character is a token separator.protected boolean
isWhitespace
(char ch) Checks whether a character is a whitespace character.final Object
next()
Returns the next token.Obtains the next token from this iteration.final void
remove()
Removing tokens is not supported.Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Methods inherited from interface java.util.Iterator
forEachRemaining
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Field Details
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HTTP_SEPARATORS
The HTTP separator characters. Defined in RFC 2616, section 2.2.- See Also:
-
headerIt
The iterator from which to obtain the next header. -
currentHeader
The value of the current header. This is the header value that includescurrentToken
. Undefined if the iteration is over. -
currentToken
The token to be returned by the next call tonextToken()
.null
if the iteration is over. -
searchPos
protected int searchPosThe position aftercurrentToken
incurrentHeader
. Undefined if the iteration is over.
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Constructor Details
-
BasicTokenIterator
Creates a new instance ofBasicTokenIterator
.- Parameters:
headerIterator
- the iterator for the headers to tokenize
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Method Details
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hasNext
public boolean hasNext()Description copied from interface:TokenIterator
Indicates whether there is another token in this iteration.- Specified by:
hasNext
in interfaceIterator<Object>
- Specified by:
hasNext
in interfaceTokenIterator
- Returns:
true
if there is another token,false
otherwise
-
nextToken
Obtains the next token from this iteration.- Specified by:
nextToken
in interfaceTokenIterator
- Returns:
- the next token in this iteration
- Throws:
NoSuchElementException
- if the iteration is already overParseException
- if an invalid header value is encountered
-
next
Returns the next token. Same asnextToken()
, but with generic return type.- Specified by:
next
in interfaceIterator<Object>
- Returns:
- the next token in this iteration
- Throws:
NoSuchElementException
- if there are no more tokensParseException
- if an invalid header value is encountered
-
remove
Removing tokens is not supported.- Specified by:
remove
in interfaceIterator<Object>
- Throws:
UnsupportedOperationException
- always
-
findNext
Determines the next token. If found, the token is stored incurrentToken
. The return value indicates the position after the token incurrentHeader
. If necessary, the next header will be obtained fromheaderIt
. If not found,currentToken
is set tonull
.- Parameters:
pos
- 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
- Throws:
ParseException
- if an invalid header value is encountered
-
createToken
Creates a new token to be returned. Called fromfindNext
after the token is identified. The default implementation simply callsString.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 tokenstart
- the index of the first token characterend
- the index after the last token character- Returns:
- a string representing the token identified by the arguments
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findTokenStart
protected int findTokenStart(int pos) Determines the starting position of the next token. This method will iterate over headers if necessary.- Parameters:
pos
- 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
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findTokenSeparator
protected int findTokenSeparator(int pos) Determines the position of the next token separator. 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:
pos
- 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
- Throws:
ParseException
- if a new token is found before a token separator. RFC 2616, section 2.1 explicitly requires a comma between tokens for#
.
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findTokenEnd
protected int findTokenEnd(int from) Determines the ending position of the current token. 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.
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isTokenSeparator
protected boolean isTokenSeparator(char ch) Checks whether a character is a token separator. 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
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isWhitespace
protected boolean isWhitespace(char ch) Checks whether a character is a whitespace character. 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
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isTokenChar
protected boolean isTokenChar(char ch) Checks whether a character is a valid token character. 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
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isHttpSeparator
protected boolean isHttpSeparator(char ch) Checks whether a character is an HTTP separator. 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
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