From ae8f44a50a29b3a955eefba13f900f94224d7c02 Mon Sep 17 00:00:00 2001
From: Dave Borowitz <dborowitz@google.com>
Date: Thu, 3 Sep 2015 16:10:09 -0400
Subject: [PATCH] DownloadConfig: Make set methods return ImmutableSet

Constructing with ImmutableSet requires less typing and less wrapping
than the previous idiom using java.util.Collections. Also, this
singleton object is supposed to be an immutable view of the global
Gerrit config, but some codepaths inadvertently left the
archiveFormats set mutable. Convey the immutability of the accessors
in the return type.

Change-Id: Id775773de1031523d51baa124c649329eaf97072
---
 .../gerrit/server/config/DownloadConfig.java  | 21 ++++++++-----------
 1 file changed, 9 insertions(+), 12 deletions(-)

diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/config/DownloadConfig.java b/gerrit-server/src/main/java/com/google/gerrit/server/config/DownloadConfig.java
index 207508d4fd..a49e715dd7 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/config/DownloadConfig.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/config/DownloadConfig.java
@@ -23,18 +23,15 @@ import com.google.inject.Singleton;
 
 import org.eclipse.jgit.lib.Config;
 
-import java.util.Collections;
 import java.util.EnumSet;
-import java.util.HashSet;
 import java.util.List;
-import java.util.Set;
 
 /** Download protocol from {@code gerrit.config}. */
 @Singleton
 public class DownloadConfig {
-  private final Set<DownloadScheme> downloadSchemes;
-  private final Set<DownloadCommand> downloadCommands;
-  private final Set<ArchiveFormat> archiveFormats;
+  private final ImmutableSet<DownloadScheme> downloadSchemes;
+  private final ImmutableSet<DownloadCommand> downloadCommands;
+  private final ImmutableSet<ArchiveFormat> archiveFormats;
 
   @Inject
   DownloadConfig(@GerritServerConfig final Config cfg) {
@@ -62,11 +59,11 @@ public class DownloadConfig {
 
     String v = cfg.getString("download", null, "archive");
     if (v == null) {
-      archiveFormats = EnumSet.allOf(ArchiveFormat.class);
+      archiveFormats = ImmutableSet.copyOf(EnumSet.allOf(ArchiveFormat.class));
     } else if (v.isEmpty() || "off".equalsIgnoreCase(v)) {
-      archiveFormats = Collections.emptySet();
+      archiveFormats = ImmutableSet.of();
     } else {
-      archiveFormats = new HashSet<>(ConfigUtil.getEnumList(cfg,
+      archiveFormats = ImmutableSet.copyOf(ConfigUtil.getEnumList(cfg,
           "download", null, "archive",
           ArchiveFormat.TGZ));
     }
@@ -77,17 +74,17 @@ public class DownloadConfig {
   }
 
   /** Scheme used to download. */
-  public Set<DownloadScheme> getDownloadSchemes() {
+  public ImmutableSet<DownloadScheme> getDownloadSchemes() {
     return downloadSchemes;
   }
 
   /** Command used to download. */
-  public Set<DownloadCommand> getDownloadCommands() {
+  public ImmutableSet<DownloadCommand> getDownloadCommands() {
     return downloadCommands;
   }
 
   /** Archive formats for downloading. */
-  public Set<ArchiveFormat> getArchiveFormats() {
+  public ImmutableSet<ArchiveFormat> getArchiveFormats() {
     return archiveFormats;
   }
 }