Access Counting CharSequence

AccessCountingCharSequence.java

public final class AccessCountingCharSequence implements CharSequence
{
  private final CharSequence str;
  private final List<Integer> accessCounts = new ArrayList<>();
  private final List<Integer> unmodifiableAccessCounts = Collections.unmodifiableList(accessCounts);

  private int accessCount = 0;

  public AccessCountingCharSequence(CharSequence str)
  {
    this.str = str;
  }

  public List<Integer> accessCounts()
  {
    return unmodifiableAccessCounts;
  }

  public void clearAccessCounts()
  {
    accessCounts.clear();
  }

  @Override
  public int length()
  {
    accessCounts.add(accessCount);
    accessCount = 0;
    return str.length();
  }

  @Override
  public char charAt(int index)
  {
    var charAt = str.charAt(index);
    accessCount++;
    return charAt;
  }

  @Override
  public CharSequence subSequence(int start, int end)
  {
    return new AccessCountingCharSequence(str.subSequence(start, end));
  }

  @Override
  public String toString()
  {
    return "CountingCharSequence: " + str;
  }
}