Make raw evaluation of policy pluggable.

/**
 * Component SPI which encapsulates the evaluation of a single or full <b>raw</b>value
 * for a {@link ConfigurationContext}.
 */
public interface ConfigValueEvaluator {

    /**
     * Evaluates single value using a {@link ConfigurationContext}.
     * @param key the config key, not null.
     * @param context the context, not null.
     * @return the value, or null.
     */
    PropertyValue evaluteRawValue(String key, ConfigurationContext context);

    /**
     * Evaluates all property values from a {@link ConfigurationContext}.
     * @param context the context, not null.
     * @return the value, or null.
     */
    Iterable<PropertyValue> evaluateRawValues(ConfigurationContext context);

}