@Override
	protected boolean matches(Object item, Description mismatchDescription) {
		U actualValue = actualValue(item);
		mismatchDescription.appendText("was ").appendValue(actualValue);
		return expectedValue.equals(actualValue);
	}
A matcher that will assert that the {@code <metric type> display xxx} shell command displays the expected value.

@param <U> the type of the value returned by the display command
@param <T> the type of metric sink fixture this is matching
@author Eric Bottard
spring-xd-test-fixtures/src/main/java/org/springframework/xd/test/fixtures/MetricHasSimpleValueMatcher.java