Split Screen / Dual Gantt Chart - A feature required by almost any planning and scheduling application is the ability to keep the data of two different models or two different sections of the same model in synch while scrolling horizontally. The FlexGantt framework includes a Dual Gantt Chart that is capable of doing exactly that. The user can split / unsplit the Gantt chart at any time. A horizontal divider can be used to resize the upper and lower part. Timeline objects can be dragged from one to another.

Internationalization - FlexGantt ships with resource bundles for English, German, Spanish, French, Swedish, Chinese and Japanese.

Relationships - It is quite common that timeline objects have some kind of relationship with each other. Project planning software for example often defines constraints between them. Some examples for constraints are: 'start after', 'finish before', 'same start', 'same end'. FlexGantt can visualize them by drawing lines betwen them. Each application has its own way of visualizing them (different colors and / or line styles for different constraints). By plugging in a custom relationship renderer it is possible to implement any kind of relationship rendering.

Lazy Loading - Depending on the application type the volume of data that needs visualization can be rather massiv. In these situations a user interface can only be fast and responsive if it uses a 'lazy loading' approach, which means that data will only be transferred from the server (or database) to the client when the user actually requests it. FlexGantt has been designed from the ground-up to support lazy loading. Example: objects that implement the tree table expansion listener interface will receive an event before the tree expands so that the child nodes of the expanding parent node can be loaded. The paging model is another example for infrastructure that supports lazy loading.

Model-View-Controller (MVC) - FlexGantt follows the same MVC approach that Swing is using. Several different models are used for various purposes. A calendar model keeps track of holidays and weekends. A paging model supports the user in loading different planning horizons, a bookmark model stores the application- and user-defined bookmarks. The primary model, however, the one that feeds the Gantt chart component with data is the Gantt chart model. It is an extension of a tree table model so that it can populate the left-hand side of the Gantt chart with data (the left-hand side is a tree table). It also returns so-called timeline objects that are displayed on the right-hand side underneath the timeline. Timeline objects represent activities, tasks, events, milestones, pretty much anything that can be placed on a timeline because it can be associated with a time point or a time span. The following graphic depicts the structure of a Gantt chart model.

Bookmarks - Users have become more and more used to the concept of bookmarks. FlexGantt supports them as well and users can use them to quickly adjust the timeline settings, so that a specific time point, granularity and horizon will be shown in the Gantt chart. The defined bookmarks are listed in a menu in the naviagtion controls. Small preview images of the bookmarked time span will be shown if the control key is down when the user clicked on the menu button.

Layers - FlexGantt uses a very unique layering approach that is known from graphics and mapping applications. Each Gantt chart consists of a set of system layers, which provide the core functionality (e.g. a drawing vertical grid lines) and a set of layers dedicated to rendering timeline objects (activities, events, milestones, ...). The picture below depicts the layer stack. Applications can add as many timeline object layers as they like, allowing them to easily group objects and show or hide them all at once. Layers also support transparency so that overlapping timeline objects can be easily identified.

Drag & Drop Grid - Timeline objects can be dragged and resized horizontally and dragged vertically. An invisible grid can be enabled during these drag & drop operations so that a timeline object can be more easily placed at a specific time. The grid gets controlled by a policy, which means that any kind of grid can be implemented. The default grid policy can be configured to make timeline objects snap to anything from millenium, centuries, decades, years, months, weeks, days, all the way to milliseconds.

Policy Controlled Behaviour - Scheduling applications vary too a large extent in the way they visualize information, edit data,  and respond to user interaction. FlexGantt's policy framework can be used to tailor the Gantt charts to these variations. Policies are small little decision makers and usually do not contain a lot of code. They are also stateless. In many cases they return flags (booleans) and commands only. The flags are used to control the program flow, while the commands are used to perform the actual modification of data (via a command stack with undo and redo capabilities).