@Override
  public boolean isInstalled(JobInstance jobInstance) {
    return getAllInstalledJobs().containsKey(jobInstance);
  }
Required constructor.

@param installationsPath the root path where all Samza jobs are installed.
@param jobConfigFactory  the {@link ConfigFactory} to use to read the job configs.
samza-rest/src/main/java/org/apache/samza/rest/proxy/installation/SimpleInstallationFinder.java