Added handling and logging of invalid access levels (#163).

src/main/java/org/gitlab4j/api/GitLabApi.java

@@ -4,6 +4,7 @@ import java.util.Collections;
 import java.util.Map;
 import java.util.Optional;
 import java.util.WeakHashMap;
+import java.util.logging.Logger;
 
 import javax.ws.rs.core.MediaType;
 import javax.ws.rs.core.Response;
@@ -22,6 +23,8 @@ import org.gitlab4j.api.utils.SecretString;
  */
 public class GitLabApi {
 
+    private final static Logger LOG = Logger.getLogger(GitLabApi.class.getName());
+
     /** GitLab4J default per page.  GitLab will ignore anything over 100. */
     public static final int DEFAULT_PER_PAGE = 100;
 
@@ -68,6 +71,15 @@ public class GitLabApi {
     private NotesApi notesApi;
     private EventsApi eventsApi;
 
+    /**
+     * Get the GitLab4J shared Logger instance.
+     *
+     * @return the GitLab4J shared Logger instance
+     */
+    public static final Logger getLogger() {
+        return (LOG);
+    }
+
     /**
      * Create a new GitLabApi instance that is logically a duplicate of this instance, with the exception off sudo state.
      *

src/main/java/org/gitlab4j/api/models/AccessLevel.java

@@ -3,12 +3,14 @@ package org.gitlab4j.api.models;
 import java.util.HashMap;
 import java.util.Map;
 
+import org.gitlab4j.api.GitLabApi;
+
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
 
 public enum AccessLevel {
 
-    NONE(0), GUEST(10), REPORTER(20), DEVELOPER(30), MASTER(40), OWNER(50);
+    INVALID(-1), NONE(0), GUEST(10), REPORTER(20), DEVELOPER(30), MASTER(40), OWNER(50);
 
     public final Integer value;
 
@@ -24,7 +26,14 @@ public enum AccessLevel {
 
     @JsonCreator
     public static AccessLevel forValue(Integer value) {
-        return valuesMap.get(value);
+
+        AccessLevel level = valuesMap.get(value);
+        if (level != null) {
+            return (level);
+        }
+
+        GitLabApi.getLogger().warning(String.format("[%d] is not a valid GitLab access level.", value));
+        return (value == null ? null : INVALID);
     }
 
     @JsonValue