Provide a way to unset blob metadata

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

@@ -190,6 +190,16 @@ public Blob reload(BlobSourceOption... options) {
    * made on the metadata generation of the current blob. If you want to update the information only
    * if the current blob metadata are at their latest version use the {@code metagenerationMatch}
    * option: {@code blob.update(newInfo, BlobTargetOption.metagenerationMatch())}.
+   * <p>
+   * Original metadata are merged with metadata in the provided {@code blobInfo}. To replace
+   * metadata instead you first have to unset them. Unsetting metadata can be done by setting the
+   * provided {@code blobInfo}'s metadata to {@code null}.
+   * </p>
+   * <p>
+   * Example usage of replacing blob's metadata:
+   * <pre>    {@code blob.update(blob.info().toBuilder().metadata(null).build());}
+   *    {@code blob.update(blob.info().toBuilder().metadata(newMetadata).build());}
+   * </pre>
    *
    * @param blobInfo new blob's information. Bucket and blob names must match the current ones
    * @param options update options
@@ -306,8 +316,7 @@ public Storage storage() {
   }
 
   /**
-   * Gets the requested blobs. If {@code infos.length == 0} an empty list is returned. If
-   * {@code infos.length > 1} a batch request is used to fetch blobs.
+   * Gets the requested blobs. A batch request is used to fetch blobs.
    *
    * @param storage the storage service used to issue the request
    * @param blobs the blobs to get
@@ -331,8 +340,12 @@ public Blob apply(BlobInfo f) {
   }
 
   /**
-   * Updates the requested blobs. If {@code infos.length == 0} an empty list is returned. If
-   * {@code infos.length > 1} a batch request is used to update blobs.
+   * Updates the requested blobs. A batch request is used to update blobs. Original metadata are
+   * merged with metadata in the provided {@code BlobInfo} objects. To replace metadata instead
+   * you first have to unset them. Unsetting metadata can be done by setting the provided
+   * {@code BlobInfo} objects metadata to {@code null}. See
+   * {@link #update(com.google.gcloud.storage.BlobInfo,
+   * com.google.gcloud.storage.Storage.BlobTargetOption...) } for a code example.
    *
    * @param storage the storage service used to issue the request
    * @param infos the blobs to update
@@ -356,8 +369,7 @@ public Blob apply(BlobInfo f) {
   }
 
   /**
-   * Deletes the requested blobs. If {@code infos.length == 0} an empty list is returned. If
-   * {@code infos.length > 1} a batch request is used to delete blobs.
+   * Deletes the requested blobs. A batch request is used to delete blobs.
    *
    * @param storage the storage service used to issue the request
    * @param blobs the blobs to delete

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

@@ -28,13 +28,16 @@
 import com.google.common.base.MoreObjects;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Lists;
 
 import java.io.Serializable;
 import java.math.BigInteger;
+import java.util.AbstractMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
+import java.util.Set;
 
 /**
  * Google Storage object metadata.
@@ -81,6 +84,14 @@ public StorageObject apply(BlobInfo blobInfo) {
   private final String contentLanguage;
   private final Integer componentCount;
 
+  public static final class ImmutableEmptyMap<K, V> extends AbstractMap<K, V> {
+
+    @Override
+    public Set<Entry<K, V>> entrySet() {
+      return ImmutableSet.of();
+    }
+  }
+
   public static final class Builder {
 
     private BlobId blobId;
@@ -99,7 +110,7 @@ public static final class Builder {
     private String md5;
     private String crc32c;
     private String mediaLink;
-    private ImmutableMap<String, String> metadata;
+    private Map<String, String> metadata;
     private Long generation;
     private Long metageneration;
     private Long deleteTime;
@@ -188,7 +199,8 @@ Builder mediaLink(String mediaLink) {
     }
 
     public Builder metadata(Map<String, String> metadata) {
-      this.metadata = metadata != null ? ImmutableMap.copyOf(metadata) : null;
+      this.metadata = metadata != null ?
+          ImmutableMap.copyOf(metadata) : Data.<Map>nullOf(ImmutableEmptyMap.class);
       return this;
     }
 
@@ -315,7 +327,7 @@ public String mediaLink() {
   }
 
   public Map<String, String> metadata() {
-    return metadata;
+    return Data.isNull(metadata) ? null : metadata;
   }
 
   public Long generation() {

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

@@ -683,15 +683,29 @@ public static Builder builder() {
   BucketInfo update(BucketInfo bucketInfo, BucketTargetOption... options);
 
   /**
-   * Update blob information.
+   * Update blob information. Original metadata are merged with metadata in the provided
+   * {@code blobInfo}. To replace metadata instead you first have to unset them. Unsetting metadata
+   * can be done by setting the provided {@code blobInfo}'s metadata to {@code null}.
+   * <p>
+   * Example usage of replacing blob's metadata:
+   * <pre>    {@code service.update(BlobInfo.builder("bucket", "name").metadata(null).build());}
+   *    {@code service.update(BlobInfo.builder("bucket", "name").metadata(newMetadata).build());}
+   * </pre>
    *
    * @return the updated blob
    * @throws StorageException upon failure
    */
   BlobInfo update(BlobInfo blobInfo, BlobTargetOption... options);
 
   /**
-   * Update blob information.
+   * Update blob information. Original metadata are merged with metadata in the provided
+   * {@code blobInfo}. To replace metadata instead you first have to unset them. Unsetting metadata
+   * can be done by setting the provided {@code blobInfo}'s metadata to {@code null}.
+   * <p>
+   * Example usage of replacing blob's metadata:
+   * <pre>    {@code service.update(BlobInfo.builder("bucket", "name").metadata(null).build());}
+   *    {@code service.update(BlobInfo.builder("bucket", "name").metadata(newMetadata).build());}
+   * </pre>
    *
    * @return the updated blob
    * @throws StorageException upon failure
@@ -826,7 +840,11 @@ public static Builder builder() {
   List<BlobInfo> get(BlobId... blobIds);
 
   /**
-   * Updates the requested blobs. A batch request is used to perform this call.
+   * Updates the requested blobs. A batch request is used to perform this call. Original metadata
+   * are merged with metadata in the provided {@code BlobInfo} objects. To replace metadata instead
+   * you first have to unset them. Unsetting metadata can be done by setting the provided
+   * {@code BlobInfo} objects metadata to {@code null}. See
+   * {@link #update(com.google.gcloud.storage.BlobInfo)} for a code example.
    *
    * @param blobInfos blobs to update
    * @return an immutable list of {@code BlobInfo} objects. If a blob does not exist or access to it

gcloud-java-storage/src/test/java/com/google/gcloud/storage/ITStorageTest.java

@@ -25,6 +25,7 @@
 import static org.junit.Assert.fail;
 
 import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
 import com.google.gcloud.RestorableState;
 import com.google.gcloud.storage.testing.RemoteGcsHelper;
 
@@ -95,8 +96,7 @@ public void testCreateBlob() {
     BlobInfo blob = BlobInfo.builder(bucket, blobName).build();
     BlobInfo remoteBlob = storage.create(blob, BLOB_BYTE_CONTENT);
     assertNotNull(remoteBlob);
-    assertEquals(blob.bucket(), remoteBlob.bucket());
-    assertEquals(blob.name(), remoteBlob.name());
+    assertEquals(blob.blobId(), remoteBlob.blobId());
     byte[] readBytes = storage.readAllBytes(bucket, blobName);
     assertArrayEquals(BLOB_BYTE_CONTENT, readBytes);
     assertTrue(storage.delete(bucket, blobName));
@@ -108,8 +108,7 @@ public void testCreateEmptyBlob() {
     BlobInfo blob = BlobInfo.builder(bucket, blobName).build();
     BlobInfo remoteBlob = storage.create(blob);
     assertNotNull(remoteBlob);
-    assertEquals(blob.bucket(), remoteBlob.bucket());
-    assertEquals(blob.name(), remoteBlob.name());
+    assertEquals(blob.blobId(), remoteBlob.blobId());
     byte[] readBytes = storage.readAllBytes(bucket, blobName);
     assertArrayEquals(new byte[0], readBytes);
     assertTrue(storage.delete(bucket, blobName));
@@ -122,8 +121,7 @@ public void testCreateBlobStream() throws UnsupportedEncodingException {
     ByteArrayInputStream stream = new ByteArrayInputStream(BLOB_STRING_CONTENT.getBytes(UTF_8));
     BlobInfo remoteBlob = storage.create(blob, stream);
     assertNotNull(remoteBlob);
-    assertEquals(blob.bucket(), remoteBlob.bucket());
-    assertEquals(blob.name(), remoteBlob.name());
+    assertEquals(blob.blobId(), remoteBlob.blobId());
     assertEquals(blob.contentType(), remoteBlob.contentType());
     byte[] readBytes = storage.readAllBytes(bucket, blobName);
     assertEquals(BLOB_STRING_CONTENT, new String(readBytes, UTF_8));
@@ -168,12 +166,28 @@ public void testUpdateBlob() {
     assertNotNull(storage.create(blob));
     BlobInfo updatedBlob = storage.update(blob.toBuilder().contentType(CONTENT_TYPE).build());
     assertNotNull(updatedBlob);
-    assertEquals(blob.bucket(), updatedBlob.bucket());
-    assertEquals(blob.name(), updatedBlob.name());
+    assertEquals(blob.blobId(), updatedBlob.blobId());
     assertEquals(CONTENT_TYPE, updatedBlob.contentType());
     assertTrue(storage.delete(bucket, blobName));
   }
 
+  @Test
+  public void testUpdateBlobReplaceMetadata() {
+    String blobName = "test-update-blob-replace-metadata";
+    BlobInfo blob = BlobInfo.builder(bucket, blobName)
+        .contentType(CONTENT_TYPE)
+        .metadata(ImmutableMap.of("k1", "a"))
+        .build();
+    assertNotNull(storage.create(blob));
+    BlobInfo updatedBlob = storage.update(blob.toBuilder().metadata(null).build());
+    assertNotNull(updatedBlob);
+    assertNull(updatedBlob.metadata());
+    updatedBlob = storage.update(blob.toBuilder().metadata(ImmutableMap.of("k2", "b")).build());
+    assertEquals(blob.blobId(), updatedBlob.blobId());
+    assertEquals(ImmutableMap.of("k2", "b"), updatedBlob.metadata());
+    assertTrue(storage.delete(bucket, blobName));
+  }
+
   @Test
   public void testUpdateBlobFail() {
     String blobName = "test-update-blob-fail";
@@ -223,8 +237,7 @@ public void testComposeBlob() {
         Storage.ComposeRequest.of(ImmutableList.of(sourceBlobName1, sourceBlobName2), targetBlob);
     BlobInfo remoteBlob = storage.compose(req);
     assertNotNull(remoteBlob);
-    assertEquals(bucket, remoteBlob.bucket());
-    assertEquals(targetBlobName, remoteBlob.name());
+    assertEquals(targetBlob.blobId(), remoteBlob.blobId());
     byte[] readBytes = storage.readAllBytes(bucket, targetBlobName);
     byte[] composedBytes = Arrays.copyOf(BLOB_BYTE_CONTENT, BLOB_BYTE_CONTENT.length * 2);
     System.arraycopy(BLOB_BYTE_CONTENT, 0, composedBytes, BLOB_BYTE_CONTENT.length,
@@ -288,8 +301,7 @@ public void testCopyBlobUpdateMetadata() {
     Storage.CopyRequest req = Storage.CopyRequest.of(bucket, sourceBlobName, targetBlob);
     BlobInfo remoteBlob = storage.copy(req);
     assertNotNull(remoteBlob);
-    assertEquals(bucket, remoteBlob.bucket());
-    assertEquals(targetBlobName, remoteBlob.name());
+    assertEquals(targetBlob.blobId(), remoteBlob.blobId());
     assertEquals(CONTENT_TYPE, remoteBlob.contentType());
     assertTrue(storage.delete(bucket, sourceBlobName));
     assertTrue(storage.delete(bucket, targetBlobName));
@@ -337,10 +349,8 @@ public void testBatchRequest() {
     assertEquals(0, updateResponse.gets().size());
     BlobInfo remoteUpdatedBlob1 = updateResponse.updates().get(0).get();
     BlobInfo remoteUpdatedBlob2 = updateResponse.updates().get(1).get();
-    assertEquals(bucket, remoteUpdatedBlob1.bucket());
-    assertEquals(bucket, remoteUpdatedBlob2.bucket());
-    assertEquals(updatedBlob1.name(), remoteUpdatedBlob1.name());
-    assertEquals(updatedBlob2.name(), remoteUpdatedBlob2.name());
+    assertEquals(sourceBlob1.blobId(), remoteUpdatedBlob1.blobId());
+    assertEquals(sourceBlob2.blobId(), remoteUpdatedBlob2.blobId());
     assertEquals(updatedBlob1.contentType(), remoteUpdatedBlob1.contentType());
     assertEquals(updatedBlob2.contentType(), remoteUpdatedBlob2.contentType());
 
@@ -515,8 +525,7 @@ public void testPostSignedUrl() throws IOException {
     connection.connect();
     BlobInfo remoteBlob = storage.get(bucket, blobName);
     assertNotNull(remoteBlob);
-    assertEquals(bucket, remoteBlob.bucket());
-    assertEquals(blob.name(), remoteBlob.name());
+    assertEquals(blob.blobId(), remoteBlob.blobId());
     assertTrue(storage.delete(bucket, blobName));
   }
 
@@ -528,11 +537,9 @@ public void testGetBlobs() {
     BlobInfo sourceBlob2 = BlobInfo.builder(bucket, sourceBlobName2).build();
     assertNotNull(storage.create(sourceBlob1));
     assertNotNull(storage.create(sourceBlob2));
-    List<BlobInfo> remoteInfos = storage.get(sourceBlob1.blobId(), sourceBlob2.blobId());
-    assertEquals(sourceBlob1.bucket(), remoteInfos.get(0).bucket());
-    assertEquals(sourceBlob1.name(), remoteInfos.get(0).name());
-    assertEquals(sourceBlob2.bucket(), remoteInfos.get(1).bucket());
-    assertEquals(sourceBlob2.name(), remoteInfos.get(1).name());
+    List<BlobInfo> remoteBlobs = storage.get(sourceBlob1.blobId(), sourceBlob2.blobId());
+    assertEquals(sourceBlob1.blobId(), remoteBlobs.get(0).blobId());
+    assertEquals(sourceBlob2.blobId(), remoteBlobs.get(1).blobId());
     assertTrue(storage.delete(bucket, sourceBlobName1));
     assertTrue(storage.delete(bucket, sourceBlobName2));
   }
@@ -545,8 +552,7 @@ public void testGetBlobsFail() {
     BlobInfo sourceBlob2 = BlobInfo.builder(bucket, sourceBlobName2).build();
     assertNotNull(storage.create(sourceBlob1));
     List<BlobInfo> remoteBlobs = storage.get(sourceBlob1.blobId(), sourceBlob2.blobId());
-    assertEquals(sourceBlob1.bucket(), remoteBlobs.get(0).bucket());
-    assertEquals(sourceBlob1.name(), remoteBlobs.get(0).name());
+    assertEquals(sourceBlob1.blobId(), remoteBlobs.get(0).blobId());
     assertNull(remoteBlobs.get(1));
     assertTrue(storage.delete(bucket, sourceBlobName1));
   }
@@ -589,11 +595,9 @@ public void testUpdateBlobs() {
     List<BlobInfo> updatedBlobs = storage.update(
         remoteBlob1.toBuilder().contentType(CONTENT_TYPE).build(),
         remoteBlob2.toBuilder().contentType(CONTENT_TYPE).build());
-    assertEquals(sourceBlob1.bucket(), updatedBlobs.get(0).bucket());
-    assertEquals(sourceBlob1.name(), updatedBlobs.get(0).name());
+    assertEquals(sourceBlob1.blobId(), updatedBlobs.get(0).blobId());
     assertEquals(CONTENT_TYPE, updatedBlobs.get(0).contentType());
-    assertEquals(sourceBlob2.bucket(), updatedBlobs.get(1).bucket());
-    assertEquals(sourceBlob2.name(), updatedBlobs.get(1).name());
+    assertEquals(sourceBlob2.blobId(), updatedBlobs.get(1).blobId());
     assertEquals(CONTENT_TYPE, updatedBlobs.get(1).contentType());
     assertTrue(storage.delete(bucket, sourceBlobName1));
     assertTrue(storage.delete(bucket, sourceBlobName2));
@@ -610,8 +614,7 @@ public void testUpdateBlobsFail() {
     List<BlobInfo> updatedBlobs = storage.update(
         remoteBlob1.toBuilder().contentType(CONTENT_TYPE).build(),
         sourceBlob2.toBuilder().contentType(CONTENT_TYPE).build());
-    assertEquals(sourceBlob1.bucket(), updatedBlobs.get(0).bucket());
-    assertEquals(sourceBlob1.name(), updatedBlobs.get(0).name());
+    assertEquals(sourceBlob1.blobId(), updatedBlobs.get(0).blobId());
     assertEquals(CONTENT_TYPE, updatedBlobs.get(0).contentType());
     assertNull(updatedBlobs.get(1));
     assertTrue(storage.delete(bucket, sourceBlobName1));