/interpreter/tags/at2-build270707/src/edu/vub/util/regexp/CharIndexed.java
http://ambienttalk.googlecode.com/ · Java · 96 lines · 9 code · 7 blank · 80 comment · 0 complexity · 1c3f9b4ae17a36950780dd2863fe242a MD5 · raw file
- /* gnu/regexp/CharIndexed.java
- Copyright (C) 1998-2001, 2004, 2006 Free Software Foundation, Inc.
- This file is part of GNU Classpath.
- GNU Classpath is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2, or (at your option)
- any later version.
- GNU Classpath is distributed in the hope that it will be useful, but
- WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- General Public License for more details.
- You should have received a copy of the GNU General Public License
- along with GNU Classpath; see the file COPYING. If not, write to the
- Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
- 02110-1301 USA.
- Linking this library statically or dynamically with other modules is
- making a combined work based on this library. Thus, the terms and
- conditions of the GNU General Public License cover the whole
- combination.
- As a special exception, the copyright holders of this library give you
- permission to link this library with independent modules to produce an
- executable, regardless of the license terms of these independent
- modules, and to copy and distribute the resulting executable under
- terms of your choice, provided that you also meet, for each linked
- independent module, the terms and conditions of the license of that
- module. An independent module is a module which is not derived from
- or based on this library. If you modify this library, you may extend
- this exception to your version of the library, but you are not
- obligated to do so. If you do not wish to do so, delete this
- exception statement from your version. */
- package edu.vub.util.regexp;
- /**
- * 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 <A HREF="mailto:wes@cacas.org">Wes Biggs</A>
- */
- public interface CharIndexed {
- /**
- * 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.
- */
- char OUT_OF_BOUNDS = '\uFFFF';
- /**
- * 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).
- *
- * @param index the offset position in the character field to examine
- * @return the character at the specified index, or the OUT_OF_BOUNDS
- * character defined by this interface.
- */
- char charAt(int index);
- /**
- * Shifts the input buffer by a given number of positions. Returns
- * true if the new cursor position is valid.
- */
- boolean move(int index);
- /**
- * Returns true if the most recent move() operation placed the cursor
- * position at a valid position in the input.
- */
- boolean isValid();
- /**
- * Returns another CharIndexed containing length characters to the left
- * of the given index. The given length is an expected maximum and
- * the returned CharIndexed may not necessarily contain so many characters.
- */
- CharIndexed lookBehind(int index, int length);
- /**
- * Returns the effective length of this CharIndexed
- */
- int length();
- }