Using extended properties to display device-dependent navigation

The IBM® Mobile Portal Accelerator Extended Properties portlet provides a set of pages to configure display attributes and rules of nodes in the navigation hierarchy.

Mobile wireless devices have a wide variety of functional capabilities and characteristics that require special consideration when targeting content for these clients. Considerations include text or graphical displays, black and white or color capabilities, and overall screen size. To address the needs of mobile clients, Mobile Portal Accelerator provides extended attributes for nodes in the mobile navigation tree and administrative tools to manage these attributes.

When a client requests a page, the aggregator compares the extended attributes of each node to the capabilities of the current device to determine the appropriate icon, title, and content to display for the device.

Each page, portlet, and URL (collectively referred to as nodes) in the mobile portal navigation hierarchy has associated extended properties or attributes that determine how and when it will be displayed. Attributes include information about associated icons and device capabilities required to render a page, portlet, or URL in the navigation tree.

Node attributes

Node attributes fall into two broad categories. The first category includes general attributes that affect how the node is displayed. The second category defines the rules that determine when to display a node.

All of the following attributes can also be specified in the portlet.xml of a portlet. The administrator still has the ability to override or define these attributes using Portal administration tools.

Display attributes

The following subsections describe the display attributes and how they affect the content seen on a client device.

Icon Attributes

Because mobile wireless devices, such as cell phones, have significantly smaller displays than PCs, the navigational view for these devices must present concise representations of nodes in the navigation hierarchy. Mobile Portal Accelerator provides extended attributes for specifying an icon and a short title for each node.

Attribute name	Description
ea.attr.default.iconResource	Image asset name from the MCS repository used to construct the best icon URL for the requesting device. MCS uses the resource name and device characteristics to return the URL of the best image for that device. This property takes precedence over Icon URL.
ea.attr.default.iconURL	Direct URL of an image file. Use this property only when an Icon Resource is not available.

Short Title

This property enables the administrator to specify a brief title for each node. The administrator can specify whether clients see the short title or the node's full title using the mwp.tag.alttitle.enable property in the mwp.properties file.

Attribute name	Description
ea.attr.default.altTitle	A brief title which may be displayed with the icon or in the event that the icon should not or cannot be displayed.

In addition, the administrator can add extended attributes which enable the specification of locale-specific short titles for each node. When the client's locale matches a locale-specific title defined for a node, the locale-specific title will be displayed rather than the non-specific title. For example, if the short title is set to Hello and a locale-specific title for France is set to Bonjour, users who view this node from a French locale see the title Bonjour and users from other locales see Hello.

Render Mode

This property enables the administrator to specify the display mode for a portlet as either normal or maximized mode.

Attribute name	Description
ea.attr.default.renderMode	Specifies the display mode of a portlet as either normal or maximized mode.

Device rules

The following sections describe the device rules and how they affect the content seen on a client device.

Device capabilities

Nodes may require specific device capabilities to render properly, perform some function, or to be meaningful at all. For example, a portlet may require a client with a color display to render properly, or it may provide a ring-tone selection feature that is meaningless on phones that do not support ring-tones. Mobile Portal Accelerator provides a set of rules based on device capability attributes that govern when to display a node within the navigation tree.

Mobile Portal Accelerator supports the following device capabilities:

Image capable
Color capable
Sound output capable
Client accept types – accepted formats for images, video, sound, and other formats.

Mobile Portal Accelerator also provides the infrastructure for defining customized device capabilities. The following device capabilities are examples of custom attributes that may be added to the attribute descriptor file. Full support for some of these capabilities may require custom aggregator changes. This list is not exhaustive and other custom attributes can be added.

Screen size
Browser name
Browser version
Screen size char
WML version
Bits per pixel
Horizontal scroll
Vertical scroll
Portrait or landscape orientation
Camera
File download

The XDIME aggregator, part of the Mobile Portal Accelerator product, compares device capability attributes with those found in the device repository to determine whether node content should be available to each requesting device.

Portlet developers can specify device capability rules directly in portlet.xml.

Device types

In addition to prerequisite device capabilities, a node may target a specific model or manufacturer of devices. Mobile Portal Accelerator provides the ability to specify the following device type rules for a node:

Manufacturer – Motorola, Ericsson, Nokia, and others
Model – specific model number(s)
Class – pda, phone

Node content may target additional classes such as flip, handset, portrait, or landscape. However, custom attributes and aggregator customization would be required.

A note about rules

All device capability and type rules are cumulative; they use the Boolean AND operator. Attributes with enumerated values such as Manufacturer use the Boolean OR operator. For example, if a portlet requires an image-capable client that is either a Nokia or Motorola phone, the corresponding attributes would be:

Image Capable = true AND
Manufacturer = "Nokia" OR "Motorola"

When a rule is not specified for a node, it is ignored and the corresponding capability of the requesting device is not considered when displaying the node.