Added Javadoc and log warning when fetching all groups, projects, or users from https://gitlab.com (#396).

Author: gmessner

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

@@ -33,14 +33,25 @@ public GroupApi(GitLabApi gitLabApi) {
     }
 
     /**
-     * Get a list of groups. (As user: my groups, as admin: all groups)
+     * <p>Get a list of groups. (As user: my groups, as admin: all groups)</p>
+     *
+     * <strong>WARNING:</strong> Do not use this method to fetch groups from https://gitlab.com,
+     * gitlab.com has many 1,000's of public groups and it will a long time to fetch all of them.
+     * Instead use {@link #getGroups(int itemsPerPage)} which will return a Pager of Group instances.
      *
      * <pre><code>GitLab Endpoint: GET /groups</code></pre>
      *
      * @return the list of groups viewable by the authenticated user
      * @throws GitLabApiException if any exception occurs
      */
     public List<Group> getGroups() throws GitLabApiException {
+
+        String url = this.gitLabApi.getGitLabServerUrl();
+        if (url.startsWith("https://gitlab.com")) {
+            GitLabApi.getLogger().warning("Fetching all groups from " + url +
+                    " may take many minutes to complete, use Pager<Group> getGroups(int) instead.");
+        }
+
         return (getGroups(getDefaultPerPage()).all());
     }
 

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

@@ -67,14 +67,25 @@ public ProjectApi(GitLabApi gitLabApi) {
     }
 
     /**
-     * Get a list of projects accessible by the authenticated user.
+     * <p>Get a list of projects accessible by the authenticated user.</p>
+     *
+     * <strong>WARNING:</strong> Do not use this method to fetch projects from https://gitlab.com,
+     * gitlab.com has many 100,000's of public projects and it will take hours to fetch all of them.
+     * Instead use {@link #getProjects(int itemsPerPage)} which will return a Pager of Project instances.
      *
      * <pre><code>GET /projects</code></pre>
      *
      * @return a list of projects accessible by the authenticated user
      * @throws GitLabApiException if any exception occurs
      */
     public List<Project> getProjects() throws GitLabApiException {
+
+       String url = this.gitLabApi.getGitLabServerUrl();
+       if (url.startsWith("https://gitlab.com")) {
+           GitLabApi.getLogger().warning("Fetching all projects from " + url +
+                   " may take many hours to complete, use Pager<Project> getProjects(int) instead.");
+       }
+
        return (getProjects(getDefaultPerPage()).all());
     }
 

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

@@ -47,14 +47,25 @@ public void disableCustomAttributes() {
     }
 
     /**
-     * Get a list of users.
+     * <p>Get a list of users.</p>
+     *
+     * <strong>WARNING:</strong> Do not use this method to fetch users from https://gitlab.com,
+     * gitlab.com has many 1,000,000's of users and it will a long time to fetch all of them.
+     * Instead use {@link #getUsers(int itemsPerPage)} which will return a Pager of Group instances.
      *
      * <pre><code>GitLab Endpoint: GET /users</code></pre>
      *
      * @return a list of Users
      * @throws GitLabApiException if any exception occurs
      */
     public List<User> getUsers() throws GitLabApiException {
+
+        String url = this.gitLabApi.getGitLabServerUrl();
+        if (url.startsWith("https://gitlab.com")) {
+            GitLabApi.getLogger().warning("Fetching all users from " + url +
+                    " may take many minutes to complete, use Pager<User> getUsers(int) instead.");
+        }
+
         return (getUsers(getDefaultPerPage()).all());
     }