@Override
    public String lookup(String key) {
        String replacement = System.getProperty(key);
        if (replacement == null) {
            replacement = System.getenv(key);
        }
        return replacement;
    }
A simple string lookup class that supports system properties and environment
variables.

@author eric.wittmann@redhat.com
common/util/src/main/java/io/apiman/common/util/ApimanStrLookup.java