public StackInfo getStack(String name, String version) {
    return stackMap.get(name + StackManager.PATH_DELIMITER + version);
  }
Obtain the stack info specified by name and version.

@param name     name of the stack
@param version  version of the stack
@return The stack corresponding to the specified name and version.
        If no matching stack exists, null is returned.
ambari-server/src/main/java/org/apache/ambari/server/stack/StackManager.java