506866: use enum for different user types, not Strings

Change-Id: Id001f68a53222c09afce158e7db1c5ba7798365d
Task-Url: https://bugs.eclipse.org/bugs/show_bug.cgi?id=506866
diff --git a/org.eclipse.mylyn.gerrit.core/src/org/eclipse/mylyn/internal/gerrit/core/client/GerritClient29.java b/org.eclipse.mylyn.gerrit.core/src/org/eclipse/mylyn/internal/gerrit/core/client/GerritClient29.java
index 315f239..293e899 100644
--- a/org.eclipse.mylyn.gerrit.core/src/org/eclipse/mylyn/internal/gerrit/core/client/GerritClient29.java
+++ b/org.eclipse.mylyn.gerrit.core/src/org/eclipse/mylyn/internal/gerrit/core/client/GerritClient29.java
@@ -71,6 +71,10 @@
 
 	final String MAY = "MAY"; //$NON-NLS-1$
 
+	private static enum UserType {
+		Author, Committer
+	}
+
 	protected GerritClient29(TaskRepository repository, Version version) {
 		super(repository, version);
 	}
@@ -482,12 +486,12 @@
 
 	private PatchSetInfo setAccountPatchSetInfo(PatchSetInfo patchSetInfo, IProgressMonitor monitor) {
 		if (patchSetInfo.getAuthor().getAccount() == null) {
-			patchSetInfo.setAuthor(
-					setUserIdentity(patchSetInfo.getAuthor().getName(), patchSetInfo.getAuthor(), "Author", monitor)); //$NON-NLS-1$
+			patchSetInfo.setAuthor(setUserIdentity(patchSetInfo.getAuthor().getName(), patchSetInfo.getAuthor(),
+					UserType.Author, monitor));
 		}
 		if (patchSetInfo.getCommitter().getAccount() == null) {
 			patchSetInfo.setCommitter(setUserIdentity(patchSetInfo.getCommitter().getName(),
-					patchSetInfo.getCommitter(), "Committer", monitor)); //$NON-NLS-1$
+					patchSetInfo.getCommitter(), UserType.Committer, monitor));
 		}
 		return patchSetInfo;
 	}
@@ -505,7 +509,7 @@
 		return accountInfo;
 	}
 
-	private UserIdentity setUserIdentity(String name, UserIdentity userIdentity, String user,
+	private UserIdentity setUserIdentity(String name, UserIdentity userIdentity, UserType user,
 			IProgressMonitor monitor) {
 		org.eclipse.mylyn.internal.gerrit.core.client.rest.AccountInfo accountInfo = null;
 		try {