Update signUrl documentation
* Removed ComputeCredentials from examples of credentials that cannot
sign URLs.
* Added a note to look at the implementations' documentation for
additional setup steps needed.
@@ -2043,10 +2043,9 @@ public interface Storage extends Service<StorageOptions> {
* {@code GOOGLE_APPLICATION_CREDENTIALS} is set or your application is running in App Engine,
* then {@code signUrl} will use that credentials to sign the URL. If the credentials passed to
* {@link StorageOptions} do not implement {@link ServiceAccountSigner} (this is the case, for
- * instance, for Compute Engine credentials and Google Cloud SDK credentials) then {@code signUrl}
- * will throw an {@link IllegalStateException} unless an implementation of
- * {@link ServiceAccountSigner} is passed using the
- * {@link SignUrlOption#signWith(ServiceAccountSigner)} option.
+ * instance, for Google Cloud SDK credentials) then {@code signUrl} will throw an
+ * {@link IllegalStateException} unless an implementation of {@link ServiceAccountSigner} is
+ * passed using the {@link SignUrlOption#signWith(ServiceAccountSigner)} option.
*
* <p>A service account signer is looked for in the following order:
* <ol>
@@ -2076,6 +2075,9 @@ public interface Storage extends Service<StorageOptions> {
* ServiceAccountCredentials.fromStream(new FileInputStream(keyPath))));
* }</pre>
*
+ * <p>Note that the {@link ServiceAccountSigner} may require additional configuration to enable
+ * URL signing. See the documentation for the implementation for more details.</p>
+ *
* @param blobInfo the blob associated with the signed URL
* @param duration time until the signed URL expires, expressed in {@code unit}. The finest
* granularity supported is 1 second, finer granularities will be truncated
