Glossary

In one paragraph

The adaptor receives a request and passes it to the application, which picks a request handler by route. For a component action, the page is taken from the session's page cache and run through the request–response loop. Bindings connect its template to Java via KeyValueCoding.

Action

A method run when a link is clicked or a form submitted. It returns action results. See component action, direct action.

Action results

What an action returns: a component (the next page), a response, or null (same page). NGActionResults.

Adaptor

The HTTP server: turns HTTP into requests and responses back. Jetty-based: ng-adaptor-jetty, or ng-adaptor-jetty-servlet.

Application

The app's main object, one per running app. Starts the adaptor, holds routes, properties and resources. You subclass NGApplication.

Association

The object behind a binding's value: a constant (NGConstantValueAssociation) or a keypath (NGKeyValueAssociation). Dynamic elements read bindings through them. NGAssociation.

Binding

An attribute on a dynamic tag, like value="$name". Dynamic ($…, resolved with KVC) or constant; can be read and set. See Templating.

Binding synchronization

By default, a child component's bindings are copied into its same-named fields before each phase, and back after. To turn it off, override synchronizesVariablesWithBindings() and use valueForBinding( "name" ). See Creating a component.

Component

An HTML template plus a Java class extending NGComponent. Has state: each use is its own instance, kept between requests. See Creating a component.

Component action

A stateful action: a method on the component that rendered the link, called on that same instance. URLs start with /no/. See Component actions.

Content

What's between a component's tags, rendered where its template has <wo:content />. NGComponentContent.

Context

The state of the request being handled: request, page, current component, element ID, session. NGContext. Transitional: it'll be split up later.

Development mode

The default when running locally. Templates, resources and routes reload on every request, and the development tools are on. Off when started with -WOMonitorEnabled YES.

Development tools

/ng/dev/… endpoints for logs, problems and evaluating code in the running app. See Development tools.

Direct action

A stateless action: somethingAction() on an NGDirectAction subclass, called at /na/ClassName/something. Needs no session. Mostly superseded by routes.

Dynamic element

A stateless building block, like <wo:str> (NGString). One instance serves every render, so state lives in associations, not fields. Subclass NGDynamicElement. See Creating a dynamic element.

Dynamic resource

Content generated for one request, like <wo:img data="$bytes" />. Served once from /nd/.

Dynamic tag

A <wo:…> tag. Stands for a dynamic element or a component; its attributes are bindings.

Element

Anything in a template's tree: a dynamic element, a component or static HTML. NGElement.

Element ID

An element's position in the page, like 0.1.5. Routes a click back to its element. NGElementID.

Key

A name resolved with KVC: name in $name.

KeyPath

Keys joined with periods: $user.address.city. A null along the way makes it null.

KeyValueCoding

The rules for finding a method or field by name. KVC for short. NGKeyValueCoding. See Templating.

Lifebeat

A regular "I'm alive" signal from a deployed app to wotaskd, so JavaMonitor can manage it.

Namespace

Keeps resources and components apart: the app's are in app, the framework's in ng, each plugin's in its own. The app in /nr/app/logo.png.

ng, ng-objects

engifer's former name, still used in code: NG classes, ng. packages, is.rebbi.ng artifacts.

Page

The top-level component, rendering the whole document. Created by pageWithName( SomePage.class ) or a route.

Page cache

A session's last 100 pages, so their component actions still work. One request at a time per page. NGPageCache.

Partial page update

Re-rendering part of a page without reloading it, with the Ajax elements. See Partial page updates.

Plugin

Adds elements, routes and resources under its own namespace. NGPlugin. See Plugins.

Properties

App configuration: an app-resources/Properties file, overridden by arguments like -WOPort 1300. See Configuration.

Public resource

A file in src/main/resources/public, served at the site root: public/robots.txt → /robots.txt.

Request

What the browser sent. Immutable once received. NGRequest.

Request handler

Answers one kind of URL: component actions (/no/), direct actions (/na/), resources (/nr/), …. NGRequestHandler.

Request–response loop

The phases a page goes through on a component action:

1. takeValuesFromRequest: form values go into bindings.
2. invokeAction: the clicked element runs its action.
3. appendToResponse: the next page renders.

A plain page view only runs appendToResponse.

Resource

A file the app uses: webserver-resources (served at /nr/app/…), app-resources (for Java code) or public (site root). See Resources.

Response

What's sent back. Make one with NGResponses.ok( … ). NGResponse.

Route

Maps a URL to a page, a function or a request handler. See Routing.

Session

A user's state between requests, including their page cache. Created on first use, kept by cookie, expires after 60 idle minutes. NGSession. See Sessions.

Tag name

The name after wo:: a short name like str, or a class name like ProductList.

Template

A component's HTML, with dynamic tags: components/Foo.html or components/Foo.wo/Foo.html.

Truthy, falsy

How a binding tested as a condition is read, as in <wo:if condition="$items">. Falsy: null, false and numbers equal to zero. Everything else is truthy, including empty strings, empty collections and the strings "false", "no" and "0". 0.5 and NaN are truthy. NGAssociationUtils.isTruthy().

Coming from WebObjects: WO also treats empty strings and collections as true. But it reads the strings "no", "false", "nil", "null" and "0" as false, and truncates numbers, so 0.5 is false. Such conditions behave differently after porting.

WOA

A built app bundle (MyApp.woa) with a launch script, in WebObjects' format. Built by vermilingua.

WOD file

WO-style element declarations, separate from the HTML. Supported for porting. See Templating.

Wrapper

A component that wraps content (layout, navigation) using <wo:content />.