private U actualValue(Object item) {
		AbstractMetricSink metric = (AbstractMetricSink) item;
		@SuppressWarnings("unchecked")
		U value = (U) metric.shell.executeCommand(metric.getDslName() + " display " + metric.getName()).getResult();
		return value;
	}
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