| /* gnu/regexp/REToken.java |
| Copyright (C) 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 gnu.java.util.regex; |
| import java.io.Serializable; |
| |
| abstract class REToken implements Serializable, Cloneable { |
| |
| protected REToken next = null; |
| protected REToken uncle = null; |
| protected int subIndex; |
| protected boolean unicodeAware = true; |
| |
| public Object clone() { |
| try { |
| REToken copy = (REToken) super.clone(); |
| return copy; |
| } catch (CloneNotSupportedException e) { |
| throw new Error(); // doesn't happen |
| } |
| } |
| |
| protected REToken(int subIndex) { |
| this.subIndex = subIndex; |
| } |
| |
| int getMinimumLength() { |
| return 0; |
| } |
| |
| int getMaximumLength() { |
| return Integer.MAX_VALUE; |
| } |
| |
| void setUncle(REToken anUncle) { |
| uncle = anUncle; |
| } |
| |
| /** Returns true if the match succeeded, false if it failed. */ |
| boolean match(CharIndexed input, REMatch mymatch) { |
| REMatch m = matchThis(input, mymatch); |
| if (m == null) return false; |
| if (next(input, m)) { |
| mymatch.assignFrom(m); |
| return true; |
| } |
| return false; |
| } |
| |
| /** Returns true if the match succeeded, false if it failed. |
| * The matching is done against this REToken only. Chained |
| * tokens are not checked. |
| * This method is used to define the default match method. |
| * Simple subclasses of REToken, for example, such that |
| * matches only one character, should implement this method. |
| * Then the default match method will work. But complicated |
| * subclasses of REToken, which needs a special match method, |
| * do not have to implement this method. |
| */ |
| REMatch matchThis(CharIndexed input, REMatch mymatch) { |
| throw new UnsupportedOperationException( |
| "This REToken does not have a matchThis method"); |
| } |
| |
| /** Returns true if the rest of the tokens match, false if they fail. */ |
| protected boolean next(CharIndexed input, REMatch mymatch) { |
| REToken nextToken = getNext(); |
| if (nextToken == null) return true; |
| return nextToken.match(input, mymatch); |
| } |
| |
| /** Returns the next REToken chained to this REToken. */ |
| REToken getNext() { |
| return (next != null ? next : uncle); |
| } |
| |
| /** Finds a match at the position specified by the given REMatch. |
| * If necessary, adds a BacktrackStack.Backtrack object to backtrackStack |
| * of the REmatch found this time so that another possible match |
| * may be found when backtrack is called. |
| * By default, nothing is added to the backtrackStack. |
| * @param CharIndexed input Input character sequence. |
| * @param mymatch Position at which a match should be found |
| * @return REMatch object if a match was found, null otherwise. |
| */ |
| REMatch findMatch(CharIndexed input, REMatch mymatch) { |
| boolean b = match(input, mymatch); |
| if (b) return mymatch; |
| return null; |
| } |
| |
| boolean returnsFixedLengthMatches() { |
| return false; |
| } |
| |
| int findFixedLengthMatches(CharIndexed input, REMatch mymatch, int max) { |
| throw new UnsupportedOperationException( |
| "This token does not support findFixedLengthMatches"); |
| } |
| |
| /** |
| * Backtrack to another possibility. |
| * Ordinary REToken cannot do anything if this method is called. |
| */ |
| REMatch backtrack(CharIndexed input, REMatch mymatch, Object param) { |
| throw new IllegalStateException("This token cannot be backtracked to"); |
| } |
| |
| boolean chain(REToken token) { |
| next = token; |
| return true; // Token was accepted |
| } |
| |
| abstract void dump(StringBuffer os); |
| |
| void dumpAll(StringBuffer os) { |
| dump(os); |
| if (next != null) next.dumpAll(os); |
| } |
| |
| public String toString() { |
| StringBuffer os = new StringBuffer(); |
| dump(os); |
| return os.toString(); |
| } |
| |
| /** |
| * Converts the character argument to lowercase. |
| * @param ch the character to be converted. |
| * @param unicodeAware If true, use java.lang.Character#toLowerCase; |
| * otherwise, only US-ASCII charactes can be converted. |
| * @return the lowercase equivalent of the character, if any; |
| * otherwise, the character itself. |
| */ |
| public static char toLowerCase(char ch, boolean unicodeAware) { |
| if (unicodeAware) return Character.toLowerCase(ch); |
| if (ch >= 'A' && ch <= 'Z') return (char)(ch + 'a' - 'A'); |
| return ch; |
| } |
| |
| /** |
| * Converts the character argument to uppercase. |
| * @param ch the character to be converted. |
| * @param unicodeAware If true, use java.lang.Character#toUpperCase; |
| * otherwise, only US-ASCII charactes can be converted. |
| * @return the uppercase equivalent of the character, if any; |
| * otherwise, the character itself. |
| */ |
| public static char toUpperCase(char ch, boolean unicodeAware) { |
| if (unicodeAware) return Character.toUpperCase(ch); |
| if (ch >= 'a' && ch <= 'z') return (char)(ch + 'A' - 'a'); |
| return ch; |
| } |
| |
| } |