Hands-On Design Patterns and Best Practices with Julia

Introducing the lazy file loader

Suppose that we are developing a file loading facility that supports lazy loading. By lazy, we are talking about not loading a file until the content is required. Let's take a look at the following code:

mutable struct FileContent    path    loaded    contentsend

The FileContent struct contains three fields:

• path: The location of the file
• loaded: A Boolean value that indicates whether the file has been loaded into memory
• contents: A byte array that contains the contents of the file

Here's the constructor for the same struct:

function FileContent(path)     ss = lstat(path)    return FileContent(path, false, zeros(UInt8, ss.size))end

As with our current design, we pre-allocate memory for the file but we do not read the file ...