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f@0: 	 * @return a {@code String} where all new line characters have been replaced by '|'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