public ImagePullPolicy createPullPolicy(String imagePullPolicy, String autoPull) {
        if (imagePullPolicy != null) {
            return ImagePullPolicy.fromString(imagePullPolicy);
        }
        if (autoPull != null) {
            AutoPullMode autoPullMode = AutoPullMode.fromString(autoPull);
            switch(autoPullMode) {
                case OFF:
                    return ImagePullPolicy.Never;
                case ALWAYS:
                    return ImagePullPolicy.Always;
                case ON:
                case ONCE:
                    return ImagePullPolicy.IfNotPresent;
            }
        }
        return ImagePullPolicy.IfNotPresent;
    }
Simple interface for a ImagePullCache manager, to load and persist the cache.
src/main/java/io/fabric8/maven/docker/service/ImagePullManager.java