Refactor Storage's delimiter support

- Minor fixes to javadoc
- Favor firstNonNull over ternary operator when possible
- Move prefix-object transformer to static function
- Simplify StorageOptions equals method

gcloud-java-storage/src/main/java/com/google/gcloud/spi/DefaultStorageRpc.java

@@ -14,6 +14,7 @@
 
 package com.google.gcloud.spi;
 
+import static com.google.common.base.MoreObjects.firstNonNull;
 import static com.google.gcloud.spi.StorageRpc.Option.DELIMITER;
 import static com.google.gcloud.spi.StorageRpc.Option.FIELDS;
 import static com.google.gcloud.spi.StorageRpc.Option.IF_GENERATION_MATCH;
@@ -58,7 +59,6 @@
 import com.google.api.services.storage.model.Objects;
 import com.google.api.services.storage.model.StorageObject;
 import com.google.common.base.Function;
-import com.google.common.base.MoreObjects;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Iterables;
 import com.google.common.collect.Lists;
@@ -167,24 +167,29 @@ public Tuple<String, Iterable<StorageObject>> list(final String bucket, Map<Opti
           .setFields(FIELDS.getString(options))
           .execute();
       Iterable<StorageObject> storageObjects = Iterables.concat(
-          objects.getItems() != null ? objects.getItems() : ImmutableList.<StorageObject>of(),
+          firstNonNull(objects.getItems(), ImmutableList.<StorageObject>of()),
           objects.getPrefixes() != null
-              ? Lists.transform(objects.getPrefixes(), new Function<String, StorageObject>() {
-                @Override
-                public StorageObject apply(String prefix) {
-                  return new StorageObject()
-                      .set("isDirectory", true)
-                      .setBucket(bucket)
-                      .setName(prefix)
-                      .setSize(BigInteger.ZERO);
-                }
-              }) : ImmutableList.<StorageObject>of());
+              ? Lists.transform(objects.getPrefixes(), objectFromPrefix(bucket))
+              : ImmutableList.<StorageObject>of());
       return Tuple.of(objects.getNextPageToken(), storageObjects);
     } catch (IOException ex) {
       throw translate(ex);
     }
   }
 
+  private static Function<String, StorageObject> objectFromPrefix(final String bucket) {
+    return new Function<String, StorageObject>() {
+      @Override
+      public StorageObject apply(String prefix) {
+        return new StorageObject()
+            .set("isDirectory", true)
+            .setBucket(bucket)
+            .setName(prefix)
+            .setSize(BigInteger.ZERO);
+      }
+    };
+  }
+
   @Override
   public Bucket get(Bucket bucket, Map<Option, ?> options) {
     try {
@@ -549,7 +554,7 @@ public String open(StorageObject object, Map<Option, ?> options) {
       HttpRequest httpRequest =
           requestFactory.buildPostRequest(url, new JsonHttpContent(jsonFactory, object));
       httpRequest.getHeaders().set("X-Upload-Content-Type",
-          MoreObjects.firstNonNull(object.getContentType(), "application/octet-stream"));
+          firstNonNull(object.getContentType(), "application/octet-stream"));
       HttpResponse response = httpRequest.execute();
       if (response.getStatusCode() != 200) {
         GoogleJsonError error = new GoogleJsonError();

gcloud-java-storage/src/main/java/com/google/gcloud/storage/BlobInfo.java

@@ -603,7 +603,7 @@ public Long updateTime() {
   /**
    * Returns {@code true} if the current blob represents a directory. This can only happen if the
    * blob is returned by {@link Storage#list(String, Storage.BlobListOption...)} when the
-   * {@link Storage.BlobListOption#currentDirectory()} option is used. If {@code true} only
+   * {@link Storage.BlobListOption#currentDirectory()} option is used. When this is the case only
    * {@link #blobId()} and {@link #size()} are set for the current blob: {@link BlobId#name()} ends
    * with the '/' character, {@link BlobId#generation()} returns {@code null} and {@link #size()} is
    * {@code 0}.
@@ -785,7 +785,7 @@ public Acl apply(ObjectAccessControl objectAccessControl) {
         }
       }));
     }
-    if (storageObject.get("isDirectory") != null) {
+    if (storageObject.containsKey("isDirectory")) {
       builder.isDirectory(Boolean.TRUE);
     }
     return builder.build();

gcloud-java-storage/src/main/java/com/google/gcloud/storage/Storage.java

@@ -694,14 +694,14 @@ public static BlobListOption prefix(String prefix) {
     }
 
     /**
-     * If specified, results are returned in a directory-like mode. Blobs whose names, aside from
-     * a possible {@link #prefix(String)}, do not contain the '/' delimiter are returned as is.
-     * Blobs whose names, aside from a possible {@link #prefix(String)}, contain the '/' delimiter,
-     * will have their name truncated after the delimiter and will be returned as {@link Blob}
-     * objects where only {@link Blob#blobId()}, {@link Blob#size()} and {@link Blob#isDirectory()}
-     * are set. For such directory blobs, ({@link BlobId#generation()} returns {@code null}),
-     * {@link Blob#size()} returns {@code 0} while {@link Blob#isDirectory()} returns {@code true}.
-     * Duplicate directory blobs are omitted.
+     * If specified, results are returned in a directory-like mode. Blobs whose names, after a
+     * possible {@link #prefix(String)}, do not contain the '/' delimiter are returned as is. Blobs
+     * whose names, after a possible {@link #prefix(String)}, contain the '/' delimiter, will have
+     * their name truncated after the delimiter and will be returned as {@link Blob} objects where
+     * only {@link Blob#blobId()}, {@link Blob#size()} and {@link Blob#isDirectory()} are set. For
+     * such directory blobs, ({@link BlobId#generation()} returns {@code null}), {@link Blob#size()}
+     * returns {@code 0} while {@link Blob#isDirectory()} returns {@code true}. Duplicate directory
+     * blobs are omitted.
      */
     public static BlobListOption currentDirectory() {
       return new BlobListOption(StorageRpc.Option.DELIMITER, true);

gcloud-java-storage/src/main/java/com/google/gcloud/storage/StorageOptions.java

@@ -106,11 +106,7 @@ public int hashCode() {
 
   @Override
   public boolean equals(Object obj) {
-    if (!(obj instanceof StorageOptions)) {
-      return false;
-    }
-    StorageOptions other = (StorageOptions) obj;
-    return baseEquals(other);
+    return obj instanceof StorageOptions && baseEquals((StorageOptions) obj);
   }
 
   public static Builder builder() {