Implementing execution context

First context

The main goal of an execution context class is to provide IN values for parameters and functions. This is achieved by a get method of HyperonContext class:

public Object get(String path) {


Whenever a parameter or function needs IN value it queries above get method providing a path. In case of parameters the path is taken from VALUE SOURCE property of an IN column definition:

In case of functions the path value is taken from path argument to ctx.getX(String path) call:

A function body can include parameter evaluation. That parameter will query the context by itself.

The developer has a full flexibility how he/she would implement the context. He or she must only remember that context is responsible for translating paths into values.

Key-value context implementation

Very simple and truly not recommended context implementation would store values in map for given paths (keys), e.g.:

policy.premiumPerDay -> 200
policy.startDate     -> 2017-01-01
policy.endDate       -> 2017-01-03

That is how HyperonContext basic constructor works:

HyperonContext ctx = new HyperonContext(
    "policy.premiumPerDay", "200",
    "policy.endDate",  "2017-01-03"

POJO-based key-value context implementation

A better approach would be to construct a mapper to retrieve values from a POJO (or more complex data structure):

public class Policy {
    private BigDecimal premiumPerDay;
    private Date startDate;
    private Date endDate;

    public BigDecimal getPremiumPerDay() {
        return premiumPerDay;

    public Date getStartDate() {
        return startDate;

    public Date getEndDate() {
        return endDate;

    setter methods and other logic

and the mapper implementation:

public class CalcContext extends HyperonContext {

    private Policy policy;

    public CalcContext(Policy policy) {
        this.policy = policy;

    public Object get(String path) {
        if ("policy.premiumPerDay".equals(path)) return policy.getPremiumPerDay();
        if ("policy.startDate".equals(path)) return policy.getStartDate();
        if ("policy.endDate".equals(path)) return policy.getEndDate();
        return null;

Once the CalcContext object is created it can be reused for subsequent calls to parameters, functions and domain attributes' values. This approach does not invoke all Policy.getX methods at context initialization. That is postponed to the moment they are really needed. This is normal that a given parameter or function uses only subset of a context (e.g. only policy.premiumPerDay). That can be altered by redesigning parameter's definition in Hyperon Studio. Mind that the execution code that calls a parameter or function:

BigDecimal premium = (BigDecimal)"", ctx);

remains fully intact as engine relies on context only.

More robust way of preparing adapters for complex data is described on next page.

More tutorials

Implementing execution context