@Override
  public boolean evaluate() {
    currentValue = supplier.get();
    return matcher.matches(currentValue);
  }
An implementation of {@link Waiter.ExplainingPredicate} that uses Hamcrest {@link Matcher} for
both predicate evaluation and explanation.
@param <T> The type of value to be evaluated via {@link Matcher}.
hbase-common/src/test/java/org/apache/hadoop/hbase/MatcherPredicate.java