/**
	 * If Java 1.4 is unavailable, the following technique may be used.
	 *
	 * @param aInput is the original String which may contain substring aOldPattern
	 * @param aOldPattern is the non-empty substring which is to be replaced
	 * @param aNewPattern is the replacement for aOldPattern
	 */
	public static String replaceSubString(final String aInput,final String aOldPattern,final String aNewPattern){
		if ( aOldPattern.equals("") ) {
			throw new IllegalArgumentException("Old pattern must have content.");
		}
		final StringBuffer result = new StringBuffer();
		//startIdx and idxOld delimit various chunks of aInput; these
		//chunks always end where aOldPattern begins
		int startIdx = 0;
		int idxOld = 0;
		while ((idxOld = aInput.indexOf(aOldPattern, startIdx)) >= 0) {
			//grab a part of aInput which does not include aOldPattern
			result.append( aInput.substring(startIdx, idxOld) );
			//add aNewPattern to take place of aOldPattern
			result.append( aNewPattern );
			
			//reset the startIdx to just after the current match, to see
			//if there are any further matches
			startIdx = idxOld + aOldPattern.length();
		}
		//the final chunk will go to the end of aInput
		result.append( aInput.substring(startIdx) );
			return result.toString();
	}