fiore@0: /*  
fiore@0:  CCmI Editor - A Collaborative Cross-Modal Diagram Editing Tool
fiore@0:   
fiore@0:  Copyright (C) 2011  Queen Mary University of London (http://ccmi.eecs.qmul.ac.uk/)
fiore@0: 
fiore@0:  This program is free software: you can redistribute it and/or modify
fiore@0:  it under the terms of the GNU General Public License as published by
fiore@0:  the Free Software Foundation, either version 3 of the License, or
fiore@0:  (at your option) any later version.
fiore@0: 
fiore@0:  This program is distributed in the hope that it will be useful,
fiore@0:  but WITHOUT ANY WARRANTY; without even the implied warranty of
fiore@0:  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
fiore@0:  GNU General Public License for more details.
fiore@0: 
fiore@0:  You should have received a copy of the GNU General Public License
fiore@0:  along with this program.  If not, see <http://www.gnu.org/licenses/>.
fiore@0: */  
fiore@0: 
fiore@0: package uk.ac.qmul.eecs.ccmi.utils;
fiore@0: 
fiore@0: /**
fiore@0:  * A utility class providing static methods to escape one or more characters. 
fiore@0:  *
fiore@0:  */
fiore@0: public class CharEscaper {
fiore@0: 	/**
fiore@0: 	 * Replaces the new line character with a '|' in the {@code String} passed as argument. 
fiore@0: 	 * The original {@code String} can be restored by passing the returned {@code String} to 
fiore@0: 	 * {@link #restoreNewline(String)}. Existing '|' characters will be escaped in order not to miss
fiore@0: 	 * them in the restore process.  
fiore@5: 	 * @param s the {@code String} to remove new line characters from
fiore@5: 	 * @return a {@code String} where all new line characters have been replaced by '|'
fiore@0: 	 */
fiore@0: 	public 	static String replaceNewline(String s){
fiore@0: 		String result = s.replace("|", "'|");
fiore@0: 		return result.replace('\n', '|');
fiore@0: 	}
fiore@0: 	
fiore@0: 	/**
fiore@0: 	 * Restores a {@code String} whose new line characters have been previously replaced by 
fiore@0: 	 * {@link #replaceNewline(String)}, to the original form.  
fiore@5: 	 * @param s the string to be restored
fiore@5: 	 * @return the restored string
fiore@0: 	 */
fiore@0: 	public static String restoreNewline(String s){
fiore@0: 		String result = s.replaceAll("([^'])\\|","$1\n");
fiore@0: 		return result.replace("'|", "|");
fiore@0: 	}
fiore@0: 	
fiore@0: 	/**
fiore@0: 	 * Escapes a set of character with another character.
fiore@0: 	 * @param s The {@code String} whose characters must be escaped. 
fiore@0: 	 * @param charsToEscape The set of characters to escape
fiore@0: 	 * @param escapeChar The escape character
fiore@0: 	 * @return a new {@code String} where characters in {@code charsToEscape} have been escaped 
fiore@0: 	 * by {@code escapeChar}.
fiore@0: 	 */
fiore@0: 	public static String escapeCharSequence(String s, CharSequence charsToEscape, char escapeChar ){
fiore@0: 		String result = s;
fiore@0: 		for(int i=0;i< charsToEscape.length();i++){
fiore@0: 			char c = charsToEscape.charAt(i);
fiore@0: 			if(c == escapeChar)
fiore@0: 				throw new IllegalArgumentException("escape character cannot be in chars to escape sequence");
fiore@0: 			for(int j=0;j<i;j++)
fiore@0: 				if(charsToEscape.charAt(j) == c)
fiore@0: 					throw new IllegalArgumentException("chars to escape sequence can only have unique characters");
fiore@0: 			result = result.replace(""+c, ""+escapeChar+c);
fiore@0: 		}
fiore@0: 		return result;
fiore@0: 	}
fiore@0: 	
fiore@0: 	/**
fiore@0: 	 * Removes an escape character preceding a set of character.
fiore@0: 	 * @param s The {@code String} containing the characters to un-escape
fiore@0: 	 * @param charsToUnescape The set of characters to the which must be un-escaped
fiore@0: 	 * @param escapeChar The escape character 
fiore@0: 	 * @return A {@code String} where the escape character preceding the characters 
fiore@0: 	 * in charsToUnescape have been removed.  
fiore@0: 	 */
fiore@0: 	public static String unescapeCharSequence(String s, CharSequence charsToUnescape, char escapeChar ){
fiore@0: 		String result = s;
fiore@0: 		for(int i=0;i< charsToUnescape.length();i++){
fiore@0: 			char c = charsToUnescape.charAt(i);
fiore@0: 			if(c == escapeChar)
fiore@0: 				throw new IllegalArgumentException("escape character cannot be in chars to escape sequence");
fiore@0: 			for(int j=0;j<i;j++)
fiore@0: 				if(charsToUnescape.charAt(j) == c)
fiore@0: 					throw new IllegalArgumentException("chars to escape sequence can only have unique characters");
fiore@0: 			result = result.replace(""+escapeChar+c,""+c);
fiore@0: 		}
fiore@0: 		return result;
fiore@0: 	}
fiore@0: 	
fiore@0: 	
fiore@0: }