Bug 223732 [Viewers] Rename StyledStringBuilder to StyledString
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/StyledStringBuilder.java
/**
	 * Sets a styler to use for the given source range. The range must be
	 * subrange of actual string of this {@link StyledStringBuilder}. Stylers
	 * previously set for that range will be overwritten.
	 * 
	 * @param offset
	 *            the start offset of the range
	 * @param length
	 *            the length of the range
	 * @param styler
	 *            the styler to set
	 * 
	 * @throws StringIndexOutOfBoundsException
	 *             if <code>start</code> is less than zero, or if offset plus
	 *             length is greater than the length of this object.
	 */
	public void setStyle(int offset, int length, Styler styler) {
		if (offset < 0 || offset + length > fBuffer.length()) {
			throw new StringIndexOutOfBoundsException(
					"Invalid offset (" + offset + ") or length (" + length + ")"); 
		}
		if (length == 0) {
			return;
		}
		if (!hasRuns() || getLastRun().offset <= offset) {
			appendStyleRun(styler, offset);
			if (offset + length != fBuffer.length()) {
				appendStyleRun(null, offset + length);
			}
			return;