Channels ▼


The Power of "In Progress"

Option 1: Data + Pending Changes

Perhaps the simplest option is to represent the data along with a (possibly empty) queue of pending updates or other work to be performed against it, as illustrated in Figure 1. This configuration is the most similar to the continuation style in [1]. However, unlike that style where we explicitly created a continuation object and appended it to a queue that was logically separate from the data, here the pending work queue is an intentional first-class part of the data structure integrated into its design and operation.

Figure 1: Deferring work via "data + pending changes."

One potential drawback to Option 1 is that it can be less flexible if we may need to interrupt and restart an operation we've split into pieces and enqueued. For example, if recalculations are affected by further user input, and multiple chunks of the recalculation work are already in the queue, we may need to traverse the queue to remove specific work items. One way to minimize this concern is to only enqueue one "next step" at a time for each long-running operation, and have the end of each chunk of work enqueue its own continuation (see sample code in [1]).

Related Reading

More Insights

Currently we allow the following HTML tags in comments:

Single tags

These tags can be used alone and don't need an ending tag.

<br> Defines a single line break

<hr> Defines a horizontal line

Matching tags

These require an ending tag - e.g. <i>italic text</i>

<a> Defines an anchor

<b> Defines bold text

<big> Defines big text

<blockquote> Defines a long quotation

<caption> Defines a table caption

<cite> Defines a citation

<code> Defines computer code text

<em> Defines emphasized text

<fieldset> Defines a border around elements in a form

<h1> This is heading 1

<h2> This is heading 2

<h3> This is heading 3

<h4> This is heading 4

<h5> This is heading 5

<h6> This is heading 6

<i> Defines italic text

<p> Defines a paragraph

<pre> Defines preformatted text

<q> Defines a short quotation

<samp> Defines sample computer code text

<small> Defines small text

<span> Defines a section in a document

<s> Defines strikethrough text

<strike> Defines strikethrough text

<strong> Defines strong text

<sub> Defines subscripted text

<sup> Defines superscripted text

<u> Defines underlined text

Dr. Dobb's encourages readers to engage in spirited, healthy debate, including taking us to task. However, Dr. Dobb's moderates all comments posted to our site, and reserves the right to modify or remove any content that it determines to be derogatory, offensive, inflammatory, vulgar, irrelevant/off-topic, racist or obvious marketing or spam. Dr. Dobb's further reserves the right to disable the profile of any commenter participating in said activities.

Disqus Tips To upload an avatar photo, first complete your Disqus profile. | View the list of supported HTML tags you can use to style comments. | Please read our commenting policy.