Mods to support merge_method (#174).

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

@@ -590,6 +590,7 @@ public class ProjectApi extends AbstractApi implements Constants {
      * visibility (optional) - Limit by visibility public, internal, or private
      * visibilityLevel (optional)
      * issuesEnabled (optional) - Enable issues for this project
+     * mergeMethod (optional) - Set the merge method used
      * mergeRequestsEnabled (optional) - Enable merge requests for this project
      * wikiEnabled (optional) - Enable wiki for this project
      * snippetsEnabled (optional) - Enable snippets for this project
@@ -629,6 +630,7 @@ public class ProjectApi extends AbstractApi implements Constants {
             .withParam("default_branch", project.getDefaultBranch())
             .withParam("description", project.getDescription())
             .withParam("issues_enabled", project.getIssuesEnabled())
+            .withParam("merge_method",  project.getMergeMethod())
             .withParam("merge_requests_enabled", project.getMergeRequestsEnabled())
             .withParam("jobs_enabled", project.getJobsEnabled())
             .withParam("wiki_enabled", project.getWikiEnabled())
@@ -822,6 +824,7 @@ public class ProjectApi extends AbstractApi implements Constants {
      * description (optional) - short project description
      * visibility (optional) - Limit by visibility public, internal, or private
      * issuesEnabled (optional) - Enable issues for this project
+     * mergeMethod (optional) - Set the merge method used
      * mergeRequestsEnabled (optional) - Enable merge requests for this project
      * wikiEnabled (optional) - Enable wiki for this project
      * snippetsEnabled (optional) - Enable snippets for this project
@@ -869,6 +872,7 @@ public class ProjectApi extends AbstractApi implements Constants {
             .withParam("default_branch", project.getDefaultBranch())
             .withParam("description", project.getDescription())
             .withParam("issues_enabled", project.getIssuesEnabled())
+            .withParam("merge_method",  project.getMergeMethod())
             .withParam("merge_requests_enabled", project.getMergeRequestsEnabled())
             .withParam("jobs_enabled", project.getJobsEnabled())
             .withParam("wiki_enabled", project.getWikiEnabled())

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

@@ -8,10 +8,38 @@ import javax.xml.bind.annotation.XmlAccessType;
 import javax.xml.bind.annotation.XmlAccessorType;
 import javax.xml.bind.annotation.XmlRootElement;
 
+import org.gitlab4j.api.utils.JacksonJsonEnumHelper;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonValue;
+
 @XmlRootElement
 @XmlAccessorType(XmlAccessType.FIELD)
 public class Project {
 
+    // Enum for the merge_method of the Project instance.
+    public enum MergeMethod {
+
+        MERGE, REBASE_MERGE, FF;
+
+        private static JacksonJsonEnumHelper<MergeMethod> enumHelper = new JacksonJsonEnumHelper<>(MergeMethod.class);
+
+        @JsonCreator
+        public static MergeMethod forValue(String value) {
+            return enumHelper.forValue(value);
+        }
+
+        @JsonValue
+        public String toValue() {
+            return (enumHelper.toString(this));
+        }
+
+        @Override
+        public String toString() {
+            return (enumHelper.toString(this));
+        }
+    }
+
     private Integer approvalsBeforeMerge;
     private Boolean archived;
     private String avatarUrl;
@@ -29,6 +57,7 @@ public class Project {
     private Boolean jobsEnabled;
     private Date lastActivityAt;
     private Boolean lfsEnabled;
+    private MergeMethod mergeMethod;
     private Boolean mergeRequestsEnabled;
     private String name;
     private Namespace namespace;
@@ -225,6 +254,19 @@ public class Project {
         return (this);
     }
 
+    public MergeMethod getMergeMethod() {
+        return mergeMethod;
+    }
+
+    public void setMergeMethod(MergeMethod mergeMethod) {
+        this.mergeMethod = mergeMethod;
+    }
+
+    public Project withMergeMethod(MergeMethod mergeMethod) {
+        this.mergeMethod = mergeMethod;
+        return (this);
+    }
+
     public Boolean getMergeRequestsEnabled() {
         return mergeRequestsEnabled;
     }

src/main/java/org/gitlab4j/api/utils/JacksonJsonEnumHelper.java

@@ -58,6 +58,17 @@ public class JacksonJsonEnumHelper<E extends Enum<E>> {
         }
     }
 
+    /**
+     * Add an enum that has a specialized name that does not fit the standard naming conventions.
+     *
+     * @param e the enum to add
+     * @param name the name for the enum
+     */
+    public void addEnum(E e, String name) {
+        valuesMap.put(name, e);
+        namesMap.put(e, name);
+    }
+
     @JsonCreator
     public E forValue(String value) {
         return valuesMap.get(value);

src/test/resources/org/gitlab4j/api/project.json

@@ -66,5 +66,6 @@
   "repository_storage": "default",
   "only_allow_merge_if_pipeline_succeeds": false,
   "only_allow_merge_if_all_discussions_are_resolved": false,
-  "request_access_enabled": false
+  "request_access_enabled": false,
+  "merge_method": "merge"
 }
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