Package org.json
Class JSONTokener
java.lang.Object
org.json.JSONTokener
- Direct Known Subclasses:
HTTPTokener
,XMLTokener
A JSONTokener takes a source string and extracts characters and tokens from
it. It is used by the JSONObject and JSONArray constructors to parse
JSON source strings.
- Version:
- 2014-05-03
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Field Summary
FieldsModifier and TypeFieldDescriptionprivate long
current read character position on the current line.private long
the number of characters read in the previous line.private boolean
flag to indicate if the end of the input has been found.private long
current read index of the input.private long
current line of the input.private char
previous character read from the input.private final Reader
Reader for the input.private boolean
flag to indicate that a previous character was requested. -
Constructor Summary
ConstructorsConstructorDescriptionJSONTokener
(InputStream inputStream) Construct a JSONTokener from an InputStream.JSONTokener
(Reader reader) Construct a JSONTokener from a Reader.Construct a JSONTokener from a string. -
Method Summary
Modifier and TypeMethodDescriptionvoid
back()
Back up one character.void
close()
Closes the underlying reader, releasing any resources associated with it.private void
Decrements the indexes for theback()
method based on the previous character read.static int
dehexchar
(char c) Get the hex value of a character (base16).boolean
end()
Checks if the end of the input has been reached.protected char
Get the last character read from the input or '\0' if nothing has been read yet.private void
incrementIndexes
(int c) Increments the internal indexes according to the previous character read and the character passed as the current character.boolean
more()
Determine if the source string still contains characters that next() can consume.char
next()
Get the next character in the source string.char
next
(char c) Consume the next character, and check that it matches a specified character.next
(int n) Get the next n characters.char
Get the next char in the string, skipping whitespace.(package private) Object
nextSimpleValue
(char c) nextString
(char quote) Return the characters up to the next close quote character.nextTo
(char delimiter) Get the text up but not including the specified character or the end of line, whichever comes first.Get the text up but not including one of the specified delimiter characters or the end of line, whichever comes first.Get the next value.char
skipTo
(char to) Skip characters until the next character is the requested character.syntaxError
(String message) Make a JSONException to signal a syntax error.syntaxError
(String message, Throwable causedBy) Make a JSONException to signal a syntax error.toString()
Make a printable string of this JSONTokener.
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Field Details
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character
private long charactercurrent read character position on the current line. -
eof
private boolean eofflag to indicate if the end of the input has been found. -
index
private long indexcurrent read index of the input. -
line
private long linecurrent line of the input. -
previous
private char previousprevious character read from the input. -
reader
Reader for the input. -
usePrevious
private boolean usePreviousflag to indicate that a previous character was requested. -
characterPreviousLine
private long characterPreviousLinethe number of characters read in the previous line.
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Constructor Details
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JSONTokener
Construct a JSONTokener from a Reader. The caller must close the Reader.- Parameters:
reader
- A reader.
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JSONTokener
Construct a JSONTokener from an InputStream. The caller must close the input stream.- Parameters:
inputStream
- The source.
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JSONTokener
Construct a JSONTokener from a string.- Parameters:
s
- A source string.
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Method Details
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back
Back up one character. This provides a sort of lookahead capability, so that you can test for a digit or letter before attempting to parse the next number or identifier.- Throws:
JSONException
- Thrown if trying to step back more than 1 step or if already at the start of the string
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decrementIndexes
private void decrementIndexes()Decrements the indexes for theback()
method based on the previous character read. -
dehexchar
public static int dehexchar(char c) Get the hex value of a character (base16).- Parameters:
c
- A character between '0' and '9' or between 'A' and 'F' or between 'a' and 'f'.- Returns:
- An int between 0 and 15, or -1 if c was not a hex digit.
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end
public boolean end()Checks if the end of the input has been reached.- Returns:
- true if at the end of the file and we didn't step back
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more
Determine if the source string still contains characters that next() can consume.- Returns:
- true if not yet at the end of the source.
- Throws:
JSONException
- thrown if there is an error stepping forward or backward while checking for more data.
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next
Get the next character in the source string.- Returns:
- The next character, or 0 if past the end of the source string.
- Throws:
JSONException
- Thrown if there is an error reading the source string.
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getPrevious
protected char getPrevious()Get the last character read from the input or '\0' if nothing has been read yet.- Returns:
- the last character read from the input.
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incrementIndexes
private void incrementIndexes(int c) Increments the internal indexes according to the previous character read and the character passed as the current character.- Parameters:
c
- the current character read.
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next
Consume the next character, and check that it matches a specified character.- Parameters:
c
- The character to match.- Returns:
- The character.
- Throws:
JSONException
- if the character does not match.
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next
Get the next n characters.- Parameters:
n
- The number of characters to take.- Returns:
- A string of n characters.
- Throws:
JSONException
- Substring bounds error if there are not n characters remaining in the source string.
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nextClean
Get the next char in the string, skipping whitespace.- Returns:
- A character, or 0 if there are no more characters.
- Throws:
JSONException
- Thrown if there is an error reading the source string.
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nextString
Return the characters up to the next close quote character. Backslash processing is done. The formal JSON format does not allow strings in single quotes, but an implementation is allowed to accept them.- Parameters:
quote
- The quoting character, either"
(double quote) or'
(single quote).- Returns:
- A String.
- Throws:
JSONException
- Unterminated string.
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nextTo
Get the text up but not including the specified character or the end of line, whichever comes first.- Parameters:
delimiter
- A delimiter character.- Returns:
- A string.
- Throws:
JSONException
- Thrown if there is an error while searching for the delimiter
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nextTo
Get the text up but not including one of the specified delimiter characters or the end of line, whichever comes first.- Parameters:
delimiters
- A set of delimiter characters.- Returns:
- A string, trimmed.
- Throws:
JSONException
- Thrown if there is an error while searching for the delimiter
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nextValue
Get the next value. The value can be a Boolean, Double, Integer, JSONArray, JSONObject, Long, or String, or the JSONObject.NULL object.- Returns:
- An object.
- Throws:
JSONException
- If syntax error.
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nextSimpleValue
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skipTo
Skip characters until the next character is the requested character. If the requested character is not found, no characters are skipped.- Parameters:
to
- A character to skip to.- Returns:
- The requested character, or zero if the requested character is not found.
- Throws:
JSONException
- Thrown if there is an error while searching for the to character
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syntaxError
Make a JSONException to signal a syntax error.- Parameters:
message
- The error message.- Returns:
- A JSONException object, suitable for throwing
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syntaxError
Make a JSONException to signal a syntax error.- Parameters:
message
- The error message.causedBy
- The throwable that caused the error.- Returns:
- A JSONException object, suitable for throwing
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toString
Make a printable string of this JSONTokener. -
close
Closes the underlying reader, releasing any resources associated with it.- Throws:
IOException
- If an I/O error occurs while closing the reader.
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