如何检查文件路径是否相对于另一个文件路径？

Question

如果我有路径：

String path = "/some/path"

如何检查其他路径是否与其相关（鉴于我要将'anotherPath'连接到'path'）？

例如：

String anotherPath = ""; // relative = true 
// will result in a full path of "/some/path"

String anotherPath = "/some/more"; // relative = true
// will result in a full path of "/some/path/some/more"

String anotherPath = "some/more"; // relative = true
// will result in a full path of "/some/path/some/more"

String anotherPath = "../../trying/go/up"; // relative = false
// would result in an INVALID full path of "/trying/go/up"

String anotherPath = "../more"; // relative = true
// will result in a full path of "/some/more"

此外，是否可以仅使用字符串而不是文件或URL对象进行这些检查？ （因为我无法写入文件系统）