public void setOffset(long offset) {
        if (offset < 0) {
            throw new SiddhiAppCreationException("'offset' cannot have negative value, but found '" + offset + "'",
                    selector, siddhiQueryContext.getSiddhiAppContext());
        }
        this.offset = offset;
    }
Processor implementation representing selector portion of the Siddhi query.
modules/siddhi-core/src/main/java/io/siddhi/core/query/selector/QuerySelector.java