Package gnu.regexp

Interface CharIndexed

  • All Known Implementing Classes:
    CharIndexedCharArray, CharIndexedInputStream, CharIndexedReader, CharIndexedString, CharIndexedStringBuffer

    public interface CharIndexed
    Defines the interface used internally so that different types of source text can be accessed in the same way. Built-in concrete classes provide support for String, StringBuffer, InputStream and char[] types. A class that is CharIndexed supports the notion of a cursor within a block of text. The cursor must be able to be advanced via the move() method. The charAt() method returns the character at the cursor position plus a given offset.
    Author:
    Wes Biggs
    • Field Summary

      Fields 
      Modifier and Type Field Description
      static char OUT_OF_BOUNDS
      Defines a constant (0xFFFF was somewhat arbitrarily chosen) that can be returned by the charAt() function indicating that the specified index is out of range.
    • Method Summary

      All Methods Instance Methods Abstract Methods 
      Modifier and Type Method Description
      char charAt​(int index)
      Returns the character at the given offset past the current cursor position in the input.
      boolean isValid()
      Returns true if the most recent move() operation placed the cursor position at a valid position in the input.
      boolean move​(int index)
      Shifts the input buffer by a given number of positions.
    • Field Detail

      • OUT_OF_BOUNDS

        static final char OUT_OF_BOUNDS
        Defines a constant (0xFFFF was somewhat arbitrarily chosen) that can be returned by the charAt() function indicating that the specified index is out of range.
        See Also:
        Constant Field Values
    • Method Detail

      • charAt

        char charAt​(int index)
        Returns the character at the given offset past the current cursor position in the input. The index of the current position is zero. It is possible for this method to be called with a negative index. This happens when using the '^' operator in multiline matching mode or the '\b' or '\<' word boundary operators. In any case, the lower bound is currently fixed at -2 (for '^' with a two-character newline).
        Parameters:
        index - the offset position in the character field to examine
        Returns:
        the character at the specified index, or the OUT_OF_BOUNDS character defined by this interface.
      • move

        boolean move​(int index)
        Shifts the input buffer by a given number of positions. Returns true if the new cursor position is valid.
      • isValid

        boolean isValid()
        Returns true if the most recent move() operation placed the cursor position at a valid position in the input.