archaius-core/src/main/java/com/netflix/config/DefaultContextualPredicate.java
@Override
    public boolean apply(@Nullable Map<String, Collection<String>> input) {
        if (null == input) {
            throw new NullPointerException();
        }
        for (Map.Entry<String, Collection<String>> entry: input.entrySet()) {
            String key = entry.getKey();                
            Collection<String> value = entry.getValue();
            if (!value.contains(getValueFromKeyFunction.apply(key))) {
                return false;
            }
        }
        return true;

    }
@Override
    public boolean apply(@Nullable Map<String, Collection<String>> input) {
        if (null == input) {
            throw new NullPointerException();
        }
        for (Map.Entry<String, Collection<String>> entry: input.entrySet()) {
            String key = entry.getKey();                
            Collection<String> value = entry.getValue();
            if (!value.contains(getValueFromKeyFunction.apply(key))) {
                return false;
            }
        }
        return true;

    }
For each key in the passed in map, this function returns true if

<li> the value derived from the key using the function (passed in from the constructor) matches <b>any</b> of the value included for the same key in the map
<li> the above holds true for <b>all</b> keys in the map