updated readme

Author: jeetchoudhary

README.md

@@ -223,26 +223,33 @@ set --rate-limit-pr-creations with appropriate value. More example below
 
 ##### Default case:
 
+By default, this feature is disabled. This will be enabled when argument ``--rate-limit-pr-creations`` will be passed
+with
+appropriate value.
+
 ```
 example usage: dockerfile-image-update all image-tag-store-repo-falcon //disabled
-example usage: dockerfile-image-update --rate-limit-pr-creations 500 all image-tag-store-repo-falcon //enabled
 ```
-By default, this feature is disabled. This will be enabled when argument ``--useratelimiting`` will be passed appropriate value 
-Above example will throttle the number of PRs cut based on default values as mentioned above i.e.,
-maximum 500 PRs could be sent within a period of 1 hour . To distribute the load uniformly and avoid sudden spikes,
-at max only 8(500/60) PRs could be sent in every 1 min. The process will go in waiting state until next PR could be sent.
 
 ##### Configuring the rate limit:
 
+Below are some examples that will throttle the number of PRs cut based on values passed to the
+argument ``--rate-limit-pr-creations``
+The argument value should be in format ``<positive_integer>-<ISO-8601_formatted_time>``.
+For example ``--rate-limit-pr-creations 60-PT1H`` would mean the tool will cut 60 PRs every hour and the rate of adding
+a new PR will be (PT1H/60) i.e. one minute.
+This will distribute the load uniformly and avoid sudden spikes, The process will go in waiting state until next PR
+could be sent.
+
+Below are some more examples:
+
 ```
-example usage: 
-    dockerfile-image-update --rate-limit-pr-creations 500 all image-tag-store-repo-falcon //DFIU can send up to 500 PRs per hour
-    dockerfile-image-update --rate-limit-pr-creations 500-per-s all image-tag-store-repo-falcon //DFIU can send up to 500 PRs per second
-    dockerfile-image-update --rate-limit-pr-creations 500-per-60s all image-tag-store-repo-falcon //DFIU can send up to 500 PRs per 60 second
-    dockerfile-image-update --rate-limit-pr-creations 500-per-m all image-tag-store-repo-falcon //DFIU can send up to 500 PRs per minute
-    dockerfile-image-update --rate-limit-pr-creations 500-per-1h all image-tag-store-repo-falcon //DFIU can send up to 500 PRs per hour
-    dockerfile-image-update --rate-limit-pr-creations 500-per-h all image-tag-store-repo-falcon //DFIU can send up to 500 PRs per hour
-    dockerfile-image-update --rate-limit-pr-creations 50perhour all image-tag-store-repo-falcon //DFIU will not impose any rate limiting as argument value is not valid
+Usage: 
+    dockerfile-image-update --rate-limit-pr-creations 60-PT1H all image-tag-store-repo-falcon //DFIU can send up to 60 PRs per hour.
+    dockerfile-image-update --rate-limit-pr-creations 500-PT1H all image-tag-store-repo-falcon //DFIU can send up to 500 PRs per hour.
+    dockerfile-image-update --rate-limit-pr-creations 86400-PT24H all image-tag-store-repo-falcon //DFIU can send up to 1 PRs per second.
+    dockerfile-image-update --rate-limit-pr-creations 1-PT1S all image-tag-store-repo-falcon //Same as above. DFIU can send up to 1 PRs per second.
+    dockerfile-image-update --rate-limit-pr-creations 5000 all image-tag-store-repo-falcon //rate limiting will be disabled because argument is not in correct format.
 ```
 
 ## Developer Guide

dockerfile-image-update/src/main/java/com/salesforce/dockerfileimageupdate/subcommands/impl/All.java

@@ -38,7 +38,7 @@ public class All implements ExecutableWithNamespace {
     @Override
     public void execute(final Namespace ns, final DockerfileGitHubUtil dockerfileGitHubUtil) throws Exception {
         loadDockerfileGithubUtil(dockerfileGitHubUtil);
-        RateLimiter rateLimiter =  RateLimiter.getRateLimiter(ns);
+        RateLimiter rateLimiter =  RateLimiter.getInstance(ns);
         String store = ns.get(Constants.STORE);
         try {
             ImageTagStore imageTagStore = ImageStoreUtil.initializeImageTagStore(this.dockerfileGitHubUtil, store);

dockerfile-image-update/src/main/java/com/salesforce/dockerfileimageupdate/subcommands/impl/Child.java

@@ -37,7 +37,7 @@ public void execute(final Namespace ns, final DockerfileGitHubUtil dockerfileGit
         String forceTag = ns.get(Constants.FORCE_TAG);
         String store = ns.get(Constants.STORE);
         ImageStoreUtil imageStoreUtil = getImageStoreUtil();
-        RateLimiter rateLimiter =  RateLimiter.getRateLimiter(ns);
+        RateLimiter rateLimiter =  RateLimiter.getInstance(ns);
         try {
             ImageTagStore imageTagStore = imageStoreUtil.initializeImageTagStore(dockerfileGitHubUtil, store);
             /* Updates store if a store is specified. */

dockerfile-image-update/src/main/java/com/salesforce/dockerfileimageupdate/subcommands/impl/Parent.java

@@ -60,7 +60,7 @@ public void execute(final Namespace ns, DockerfileGitHubUtil dockerfileGitHubUti
         PullRequests pullRequests = getPullRequests();
         GitHubPullRequestSender pullRequestSender = getPullRequestSender(dockerfileGitHubUtil, ns);
         GitForkBranch gitForkBranch = getGitForkBranch(ns);
-        RateLimiter rateLimiter = RateLimiter.getRateLimiter(ns);
+        RateLimiter rateLimiter = RateLimiter.getInstance(ns);
         log.info("Finding Dockerfiles with the given image...");
 
         Integer gitApiSearchLimit = ns.get(Constants.GIT_API_SEARCH_LIMIT);

dockerfile-image-update/src/main/java/com/salesforce/dockerfileimageupdate/utils/RateLimit.java

@@ -14,8 +14,8 @@
  * @see RateLimiter
  */
 public class RateLimit {
-    public static final String ERROR_MESSAGE = "Unexpected format or unit encountered, valid input is " +
-            "<integer>-<ISO-8601_formatted_time> Example: 500-PT1S means(500 per second) \n" +
+    private static final String ERROR_MESSAGE = "Unexpected format or unit encountered, valid input is " +
+            "<positive_integer>-<ISO-8601_formatted_time> Example: 500-PT1S means(500 per second) \n" +
             "500-PT1M means(500 per Minute)";
     private static final Logger log = LoggerFactory.getLogger(RateLimit.class);
     private final long rate; //Maximum count of PRs to be sent per rLimitDuration

dockerfile-image-update/src/main/java/com/salesforce/dockerfileimageupdate/utils/RateLimiter.java

@@ -75,7 +75,7 @@ public RateLimiter() {
      * null otherwise.
      * @see net.sourceforge.argparse4j.inf.Namespace Namespace
      */
-    public static RateLimiter getRateLimiter(Namespace ns) {
+    public static RateLimiter getInstance(Namespace ns) {
         String rateLimitPRCreation = ns.get(Constants.RATE_LIMIT_PR_CREATION);
         RateLimiter rateLimiter = null;
 

dockerfile-image-update/src/test/java/com/salesforce/dockerfileimageupdate/utils/RateLimiterTest.java

@@ -79,7 +79,7 @@ public void testGetRateLimiter(String envVariableVal, Class expectedReturnType,
         Map<String, Object> nsMap = ImmutableMap.of(
                 Constants.RATE_LIMIT_PR_CREATION, envVariableVal);
         Namespace ns = new Namespace(nsMap);
-        RateLimiter rateLimiter = RateLimiter.getRateLimiter(ns);
+        RateLimiter rateLimiter = RateLimiter.getInstance(ns);
 
         if (isnull) {
             assertNull(rateLimiter);