Mods to use enums for archive format.

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

 package org.gitlab4j.api;
 
+import java.util.HashMap;
+import java.util.Map;
+
 import org.gitlab4j.api.utils.JacksonJsonEnumHelper;
 
 import com.fasterxml.jackson.annotation.JsonCreator;
@@ -438,4 +441,41 @@ public interface Constants {
             return (enumHelper.toString(this));
         }
     }
+
+    /** Enum to specify the format of a downloaded archive. */
+    public enum ArchiveFormat {
+
+        BZ2, TAR, TAR_BZ2, TAR_GZ, TB2, TBZ, TBZ2, ZIP;
+
+        private final String value;
+
+        ArchiveFormat() {
+            this.value = name().toLowerCase().replace('_', '.');
+        }
+
+        private static Map<String, ArchiveFormat> valuesMap = new HashMap<String, ArchiveFormat>(8);
+        static {
+            for (ArchiveFormat archiveFormat : ArchiveFormat.values())
+                valuesMap.put(archiveFormat.value, archiveFormat);
+        }
+
+        public static ArchiveFormat forValue(String value) throws GitLabApiException {
+
+            if (value == null || value.trim().isEmpty()) {
+                return (null);
+            }
+
+            ArchiveFormat archiveFormat = valuesMap.get(value);
+            if (archiveFormat != null) {
+                return (archiveFormat);
+            }
+
+            throw new GitLabApiException("Invalid format! Options are tar.gz, tar.bz2, tbz, tbz2, tb2, bz2, tar, and zip.");
+        }
+
+        @Override
+        public String toString() {
+            return (value);
+        }
+    }
 }

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

@@ -7,10 +7,8 @@ import java.io.UnsupportedEncodingException;
 import java.net.URLEncoder;
 import java.nio.file.Files;
 import java.nio.file.StandardCopyOption;
-import java.util.HashSet;
 import java.util.List;
 
-import java.util.Set;
 import javax.ws.rs.core.Form;
 import javax.ws.rs.core.GenericType;
 import javax.ws.rs.core.MediaType;
@@ -29,19 +27,6 @@ import org.gitlab4j.api.utils.FileUtils;
  */
 public class RepositoryApi extends AbstractApi {
 
-    private static final Set<String> validFormat = new HashSet<String>(){
-      {
-        add("tar.bz2");
-        add("tbz");
-        add("tbz2");
-        add("tb2");
-        add("bz2");
-        add("tar");
-        add("zip");
-        add("tar.gz");
-      }
-    };
-
     public RepositoryApi(GitLabApi gitLabApi) {
         super(gitLabApi);
     }
@@ -451,29 +436,44 @@ public class RepositoryApi extends AbstractApi {
      *
      * GET /projects/:id/repository/archive
      *
-     * While gitlab-ce has a bug when you try to download file archives with format by using "&format=zip(or tar... etc.)",
-     * there is a solution to request .../archive.:format instead of .../archive?format=:format.
-     * So we must check format if it is valid.
+     * @param projectId the ID of the project
+     * @param sha the SHA of the archive to get
+     * @param format The archive format, defaults to "tar.gz" if null
+     * @return an input stream that can be used to save as a file or to read the content of the archive
+     * @throws GitLabApiException if format is not a valid archive format or any exception occurs
+     */
+    public InputStream getRepositoryArchive(Integer projectId, String sha, String format) throws GitLabApiException {
+        ArchiveFormat archiveFormat = ArchiveFormat.forValue(format);
+        return (getRepositoryArchive(projectId, sha, archiveFormat));
+    }
+
+    /**
+     * Get an archive of the complete repository by SHA (optional).
      *
-     * Issue:  https://gitlab.com/gitlab-org/gitlab-ce/issues/45992
-     *         https://gitlab.com/gitlab-com/support-forum/issues/3067
+     * GET /projects/:id/repository/archive
      *
      * @param projectId the ID of the project
      * @param sha the SHA of the archive to get
-     * @param format The archive format. Default is tar.gz. Options are tar.gz, tar.bz2, tbz, tbz2,
-     * tb2, bz2, tar, zip
-     * @return an input stream that can be used to save as a file
-     * or to read the content of the archive
+     * @param format The archive format, defaults to TAR_GZ if null
+     * @return an input stream that can be used to save as a file or to read the content of the archive
      * @throws GitLabApiException if any exception occurs
      */
-    public InputStream getRepositoryArchive(Integer projectId, String sha, String format) throws GitLabApiException {
+    public InputStream getRepositoryArchive(Integer projectId, String sha, ArchiveFormat format) throws GitLabApiException {
 
-        // Throws a GitLabApiException if format is invalid
-        format = checkFormat(format);
+        if (format == null) {
+            format = ArchiveFormat.TAR_GZ;
+        }
 
+        /*
+         * Gitlab-ce has a bug when you try to download file archives with format by using "&format=zip(or tar... etc.)",
+         * there is a solution to request .../archive.:format instead of .../archive?format=:format.
+         *
+         * Issue:  https://gitlab.com/gitlab-org/gitlab-ce/issues/45992
+         *         https://gitlab.com/gitlab-com/support-forum/issues/3067
+         */
         Form formData = new GitLabApiForm().withParam("sha", sha);
         Response response = getWithAccepts(Response.Status.OK, formData.asMap(), MediaType.MEDIA_TYPE_WILDCARD,
-                  "projects", projectId, "repository", "archive", ".", format);
+                  "projects", projectId, "repository", "archive", ".", format.toString());
         return (response.readEntity(InputStream.class));
     }
 
@@ -518,29 +518,47 @@ public class RepositoryApi extends AbstractApi {
      *
      * GET /projects/:id/repository/archive
      *
-     * While gitlab-ce has a bug when you try to download file archives with format by using "&format=zip(or tar... etc.)",
-     * there is a solution to request .../archive.:format instead of .../archive?format=:format.
-     * So we must check format if it is valid.
+     * @param projectId the ID of the project
+     * @param sha the SHA of the archive to get
+     * @param directory the File instance of the directory to save the archive to, if null will use "java.io.tmpdir"
+     * @param format The archive format, defaults to "tar.gz" if null
+     * @return a File instance pointing to the downloaded instance
+     * @throws GitLabApiException if format is not a valid archive format or any exception occurs
+     */
+    public File getRepositoryArchive(Integer projectId, String sha, File directory, String format) throws GitLabApiException {
+        ArchiveFormat archiveFormat = ArchiveFormat.forValue(format);
+        return (getRepositoryArchive(projectId, sha, directory, archiveFormat));
+    }
+
+    /**
+     * Get an archive of the complete repository by SHA (optional) and saves to the specified directory.
+     * If the archive already exists in the directory it will be overwritten.
      *
-     * Issue:  https://gitlab.com/gitlab-org/gitlab-ce/issues/45992
-     *         https://gitlab.com/gitlab-com/support-forum/issues/3067
+     * GET /projects/:id/repository/archive
      *
      * @param projectId the ID of the project
      * @param sha the SHA of the archive to get
      * @param directory the File instance of the directory to save the archive to, if null will use "java.io.tmpdir"
-     * @param format The archive format. Default is tar.gz. Options are tar.gz, tar.bz2, tbz, tbz2,
-     * tb2, bz2, tar, zip
+     * @param format The archive format, defaults to TAR_GZ if null
      * @return a File instance pointing to the downloaded instance
      * @throws GitLabApiException if any exception occurs
      */
-    public File getRepositoryArchive(Integer projectId, String sha, File directory, String format) throws GitLabApiException {
+    public File getRepositoryArchive(Integer projectId, String sha, File directory, ArchiveFormat format) throws GitLabApiException {
 
-        // Throws a GitLabApiException if format is invalid
-        format = checkFormat(format);
+        if (format == null) {
+            format = ArchiveFormat.TAR_GZ;
+        }
 
+        /*
+         * Gitlab-ce has a bug when you try to download file archives with format by using "&format=zip(or tar... etc.)",
+         * there is a solution to request .../archive.:format instead of .../archive?format=:format.
+         *
+         * Issue:  https://gitlab.com/gitlab-org/gitlab-ce/issues/45992
+         *         https://gitlab.com/gitlab-com/support-forum/issues/3067
+         */
         Form formData = new GitLabApiForm().withParam("sha", sha);
         Response response = getWithAccepts(Response.Status.OK, formData.asMap(), MediaType.MEDIA_TYPE_WILDCARD,
-            "projects", projectId, "repository", "archive", ".", format);
+            "projects", projectId, "repository", "archive", ".", format.toString());
 
         try {
 
@@ -642,42 +660,4 @@ public class RepositoryApi extends AbstractApi {
     public Pager<Contributor> getContributors(Integer projectId, int itemsPerPage) throws GitLabApiException {
         return new Pager<Contributor>(this, Contributor.class, itemsPerPage, null, "projects", projectId, "repository", "contributors");
     }
-
-    /*   gitlab-ce/lib/gitlab/git/repository.rb #386   */
-    /*
-        extension =
-            case format
-            when "tar.bz2", "tbz", "tbz2", "tb2", "bz2"
-                "tar.bz2"
-            when "tar"
-                "tar"
-            when "zip"
-                "zip"
-            else
-                # everything else should fall back to tar.gz
-                "tar.gz"
-            end
-    */
-    /**
-     * While gitlab-ce has a bug when you try to download file archives with format by using "&format=zip(or tar... etc.)",
-     * there is a solution to request .../archive.:format instead of .../archive?format=:format.
-     * We must check format if it is valid.
-     *
-     * Issue:  https://gitlab.com/gitlab-org/gitlab-ce/issues/45992
-     *         https://gitlab.com/gitlab-com/support-forum/issues/3067
-     *
-     * @param format The archive format. Default is tar.gz. Options are tar.gz, tar.bz2, tbz, tbz2,
-     * tb2, bz2, tar, zip
-     * @return A valid format. Default is tar.gz.
-     */
-    private String checkFormat(String format) throws GitLabApiException {
-
-        if(format == null || format.isEmpty())
-            return "tar.gz";
-
-        if(!validFormat.contains(format))
-            throw new GitLabApiException("Invalid format! Options are tar.gz, tar.bz2, tbz, tbz2, tb2, bz2, tar, zip.");
-
-        return format;
-    }
 }