public SampleFamily increase(String range) {
        Preconditions.checkArgument(!Strings.isNullOrEmpty(range));
        if (this == EMPTY) {
            return EMPTY;
        }
        return SampleFamily.build(
            this.context,
            Arrays.stream(samples)
                  .map(sample -> sample.increase(
                      range,
                      context.metricName,
                      (lowerBoundValue, unused) -> sample.value - lowerBoundValue
                  ))
                  .toArray(Sample[]::new)
        );
    }
Following operations are used in DSL
oap-server/analyzer/meter-analyzer/src/main/java/org/apache/skywalking/oap/meter/analyzer/dsl/SampleFamily.java