Package org.terrier.utility

Class Token

  • All Implemented Interfaces:
    java.io.Serializable
    public class Token
extends java.lang.Object
implements java.io.Serializable
    Describes the input token stream.
    See Also:
    Serialized Form

    • Field Summary

      Fields 
      Modifier and Type Field Description
      int beginColumn
      The column number of the first character of this Token.
      int beginLine
      The line number of the first character of this Token.
      int endColumn
      The column number of the last character of this Token.
      int endLine
      The line number of the last character of this Token.
      java.lang.String image
      The string image of the token.
      int kind
      An integer that describes the kind of this token.
      Token next
      A reference to the next regular (non-special) token from the input stream.
      Token specialToken
      This field is used to access special tokens that occur prior to this token, but after the immediately preceding regular (non-special) token.

    • Constructor Summary

      Constructors 
      Constructor Description
      Token()
      No-argument constructor
      Token​(int kind)
      Constructs a new token for the specified Image.
      Token​(int kind, java.lang.String image)
      Constructs a new token for the specified Image and Kind.

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      java.lang.Object getValue()
      An optional attribute value of the Token.
      static Token newToken​(int ofKind)  
      static Token newToken​(int ofKind, java.lang.String image)
      Returns a new Token object, by default.
      java.lang.String toString()
      Returns the image.

      • Methods inherited from class java.lang.Object

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

    • Field Detail

      • kind

        public int kind
        An integer that describes the kind of this token. This numbering system is determined by JavaCCParser, and a table of these numbers is stored in the file ...Constants.java.

      • beginLine

        public int beginLine
        The line number of the first character of this Token.

      • beginColumn

        public int beginColumn
        The column number of the first character of this Token.

      • endLine

        public int endLine
        The line number of the last character of this Token.

      • endColumn

        public int endColumn
        The column number of the last character of this Token.

      • image

        public java.lang.String image
        The string image of the token.

      • next

        public Token next
        A reference to the next regular (non-special) token from the input stream. If this is the last token from the input stream, or if the token manager has not read tokens beyond this one, this field is set to null. This is true only if this token is also a regular token. Otherwise, see below for a description of the contents of this field.

      • specialToken

        public Token specialToken
        This field is used to access special tokens that occur prior to this token, but after the immediately preceding regular (non-special) token. If there are no such special tokens, this field is set to null. When there are more than one such special token, this field refers to the last of these special tokens, which in turn refers to the next previous special token through its specialToken field, and so on until the first special token (whose specialToken field is null). The next fields of special tokens refer to other special tokens that immediately follow it (without an intervening regular token). If there is no such token, this field is null.

    • Constructor Detail

      • Token

        public Token()
        No-argument constructor

      • Token

        public Token​(int kind)
        Constructs a new token for the specified Image.

      • Token

        public Token​(int kind,
             java.lang.String image)
        Constructs a new token for the specified Image and Kind.

    • Method Detail

      • getValue

        public java.lang.Object getValue()
        An optional attribute value of the Token. Tokens which are not used as syntactic sugar will often contain meaningful values that will be used later on by the compiler or interpreter. This attribute value is often different from the image. Any subclass of Token that actually wants to return a non-null value can override this method as appropriate.

      • toString

        public java.lang.String toString()
        Returns the image.
        Overrides:
        toString in class java.lang.Object

      • newToken

        public static Token newToken​(int ofKind,
                             java.lang.String image)
        Returns a new Token object, by default. However, if you want, you can create and return subclass objects based on the value of ofKind. Simply add the cases to the switch for all those special cases. For example, if you have a subclass of Token called IDToken that you want to create if ofKind is ID, simply add something like : case MyParserConstants.ID : return new IDToken(ofKind, image); to the following switch statement. Then you can cast matchedToken variable to the appropriate type and use sit in your lexical actions.

      • newToken

        public static Token newToken​(int ofKind)