public HostFetcher createHostFetcher(SlobrokPolicy policy, int percent) {
            return new TargetCachingSlobrokHostFetcher(slobrokHostPatternGenerator, policy, percent);
        }
Class parsing the semicolon separated parameter string and exposes the appropriate value to the policy.
documentapi/src/main/java/com/yahoo/documentapi/messagebus/protocol/ContentPolicy.java