@Override public String toString() { StringBuilder builder = new StringBuilder(); builder.append("[ "); boolean first = true; if (isConnectionChanged()) { builder.append("CONN"); first = false; } if (isValueChanged()) { if (!first) { builder.append(" | "); } builder.append("VAL"); first = false; } if (isExceptionChanged()) { if (!first) { builder.append(" | "); } builder.append("EXC"); } builder.append(" ]"); return builder.toString(); }