public Collection<ExtensionInfo> getExtensions(String name) {
    Collection<ExtensionInfo> extensions = new HashSet<>();
    for (ExtensionInfo extension: extensionMap.values()) {
      if (extension.getName().equals(name)) {
	  extensions.add(extension);
      }
    }
    return extensions;
  }
Obtain all extensions for the given name.

@param name  extension name
@return A collection of all extensions with the given name.
        If no extensions match the specified name, an empty collection is returned.
ambari-server/src/main/java/org/apache/ambari/server/stack/StackManager.java