public String execute(ComplexEvent event) {
        if (conditionExecutor.execute(event)) {
            return key;
        }
        return null;
    }
Range partition executor will compute whether a given {@link ComplexEvent} belongs to a pre-defined range and
returns respective range key.
modules/siddhi-core/src/main/java/io/siddhi/core/partition/executor/RangePartitionExecutor.java