Package org.json

Class JSONTokener

  • public class JSONTokener
extends Object
    Parses a JSON (RFC 4627) encoded string into the corresponding object. Most clients of this class will use only need the constructor and nextValue() method. Example usage: 
     String json = "{"
         + "  \"query\": \"Pizza\", "
         + "  \"locations\": [ 94043, 90210 ] "
         + "}";

 JSONObject object = (JSONObject) new JSONTokener(json).nextValue();
 String query = object.getString("query");
 JSONArray locations = object.getJSONArray("locations");

    For best interoperability and performance use JSON that complies with RFC 4627, such as that generated by JSONStringer. For legacy reasons this parser is lenient, so a successful parse does not indicate that the input string was valid JSON. All of the following syntax errors will be ignored:

    • End of line comments starting with // or # and ending with a newline character.
    • C-style comments starting with /* and ending with */. Such comments may not be nested.
    • Strings that are unquoted or 'single quoted'.
    • Hexadecimal integers prefixed with 0x or 0X.
    • Octal integers prefixed with 0.
    • Array elements separated by ;.
    • Unnecessary array separators. These are interpreted as if null was the omitted value.
    • Key-value pairs separated by = or =>.
    • Key-value pairs separated by ;.

    Each tokener may be used to parse a single JSON string. Instances of this class are not thread safe. Although this class is nonfinal, it was not designed for inheritance and should not be subclassed. In particular, self-use by overrideable methods is not specified. See Effective Java Item 17, "Design and Document or inheritance or else prohibit it" for further information.

    • Constructor Summary

      Constructors 
      Constructor Description
      JSONTokener​(String in)  

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void back()
      Unreads the most recent character of input.
      static int dehexchar​(char hex)
      Returns the integer [0..15] value for the given hex character, or -1 for non-hex input.
      boolean more()
      Returns true until the input has been exhausted.
      char next()
      Returns the next available character, or the null character '\0' if all input has been exhausted.
      char next​(char c)
      Returns the next available character if it equals c.
      String next​(int length)
      Returns the next length characters of the input.
      char nextClean()
      Returns the next character that is not whitespace and does not belong to a comment.
      String nextString​(char quote)
      Returns the string up to but not including quote, unescaping any character escape sequences encountered along the way.
      String nextTo​(char excluded)
      Equivalent to nextTo(String.valueOf(excluded)).
      String nextTo​(String excluded)
      Returns the trimmed string holding the characters up to but not including the first of: any character in excluded a newline character '\n' a carriage return '\r'
      Object nextValue()
      Returns the next value from the input.
      void skipPast​(String thru)
      Advances past all input up to and including the next occurrence of thru.
      char skipTo​(char to)
      Advances past all input up to but not including the next occurrence of to.
      JSONException syntaxError​(String message)
      Returns an exception containing the given message plus the current position and the entire input string.
      String toString()
      Returns the current position and the entire input string.

    • Constructor Detail

      • JSONTokener

        public JSONTokener​(String in)
        Parameters:
        in - JSON encoded string. Null is not permitted and will yield a tokener that throws NullPointerExceptions when methods are called.

    • Method Detail

      • nextString

        public String nextString​(char quote)
                  throws JSONException
        Returns the string up to but not including quote, unescaping any character escape sequences encountered along the way. The opening quote should have already been read. This consumes the closing quote, but does not include it in the returned string.
        Parameters:
        quote - either ' or ".
        Throws:
        JSONException

      • syntaxError

        public JSONException syntaxError​(String message)
        Returns an exception containing the given message plus the current position and the entire input string.

      • toString

        public String toString()
        Returns the current position and the entire input string.
        Overrides:
        toString in class Object

      • more

        public boolean more()
        Returns true until the input has been exhausted.

      • next

        public char next()
        Returns the next available character, or the null character '\0' if all input has been exhausted. The return value of this method is ambiguous for JSON strings that contain the character '\0'.

      • next

        public char next​(char c)
          throws JSONException
        Returns the next available character if it equals c. Otherwise an exception is thrown.
        Throws:
        JSONException

      • nextClean

        public char nextClean()
               throws JSONException
        Returns the next character that is not whitespace and does not belong to a comment. If the input is exhausted before such a character can be found, the null character '\0' is returned. The return value of this method is ambiguous for JSON strings that contain the character '\0'.
        Throws:
        JSONException

      • next

        public String next​(int length)
            throws JSONException
        Returns the next length characters of the input.

        The returned string shares its backing character array with this tokener's input string. If a reference to the returned string may be held indefinitely, you should use new String(result) to copy it first to avoid memory leaks.

        Throws:
        JSONException - if the remaining input is not long enough to satisfy this request.

      • nextTo

        public String nextTo​(String excluded)
        Returns the trimmed string holding the characters up to but not including the first of:
        • any character in excluded
        • a newline character '\n'
        • a carriage return '\r'

        The returned string shares its backing character array with this tokener's input string. If a reference to the returned string may be held indefinitely, you should use new String(result) to copy it first to avoid memory leaks.

        Returns:
        a possibly-empty string

      • nextTo

        public String nextTo​(char excluded)
        Equivalent to nextTo(String.valueOf(excluded)).

      • skipPast

        public void skipPast​(String thru)
        Advances past all input up to and including the next occurrence of thru. If the remaining input doesn't contain thru, the input is exhausted.

      • skipTo

        public char skipTo​(char to)
        Advances past all input up to but not including the next occurrence of to. If the remaining input doesn't contain to, the input is unchanged.

      • back

        public void back()
        Unreads the most recent character of input. If no input characters have been read, the input is unchanged.

      • dehexchar

        public static int dehexchar​(char hex)
        Returns the integer [0..15] value for the given hex character, or -1 for non-hex input.
        Parameters:
        hex - a character in the ranges [0-9], [A-F] or [a-f]. Any other character will yield a -1 result.