StringBuilderWrapper.java

public class StringBuilderWrapper implements CharSequence {

	private StringBuilder sb;
	
	public StringBuilderWrapper(String s) {
		this.sb = new StringBuilder(s);
	}

	public int length() {
		return sb.length();
	}

	public char charAt(int index) {
		return sb.charAt(index);
	}

	public CharSequence subSequence(int start, int end) {
		return sb.subSequence(start, end);
	}
	
	public StringBuilderWrapper replace(CharSequence a, CharSequence b) {
		String aa = a.toString();
		String bb = b.toString();
		
		int indexOf;
		int from = 0;
		while((indexOf= sb.indexOf(aa, from)) >= 0) {
			sb.replace(indexOf, indexOf + aa.length() , bb);
			from = indexOf + bb.length(); // to avoid recursion problem
		}
		
		return this;
	}
	
	public String toString() {
		return sb.toString();
	}
	
}