Pagination for devices with small memory buffers

For the tree navigation view, the HTML pagination segments pages with various navigation links into multiple pages. This enables devices with memory constraints to be able to view a larger HTML page than can be held in memory all at one time.

The HTML pagination option is available only to HTML (or any derivative of HTML such as cHTML and xHTML) type devices. There are several differences from the standard tree navigation view:

The header logo image is not rendered and it is replaced with the IBM® WebSphere® Portal title.
Navigation link icons are not supported.
Only the immediate child page, URL, and portlet links are displayed.

The HTML pagination is enabled for a device by specifying the following property within mwp.properties:

mwp.tree.pagination.max.buffer.match=5200

This value represents the maximum buffer size in bytes to match on. Any devices with a buffer size equal to or less than this value will have their HTML pages paginated. The default value currently matches many of the early generation I-mode devices. To enable HTML pagination for another device, find the maxhtmlpage device policy value for a particular device and make sure that the property is equal to or greater than that value. If you increase the value of this property, pagination will also occur for other devices with buffer sizes that match this value.

HTML pagination is determined by the amount of buffer space available in the device. The XDIME aggregator computes the amount of space consumed by the page and sends the maximum allowed links by the device. If the device can handle only a subset of the links on a page, next and previous links are included for navigating among the paginated pages.

For the XDIME aggregator to compute the amount of space a page consumes, two properties are required for the computation:

mwp.tree.pagination.page.overhead.size=1500
mwp.tree.pagination.link.size=20

In addition, the custom property navigation.expansion.defaultstate should be set to true in the Resource Environment Providers list (located in the WebSphere Application Server Integrated Solutions Console).

The page overhead size property estimates the maximum number of bytes that any given page consumes for the markup, plus any images downloaded by the client, minus navigation links, minus any page specific titles. This property is very important because it determines how many bytes are available to add links given the overhead size of the page and images. You should typically include only small gif images, and custom aggregators should generate simple headers and footers. The best way to determine this value is:

With a browser, view the page source of the root page after the user logs in.
Copy the HTML source into your favorite editor.
Delete any navigation links, such as <a href=""></a><br/>.
Delete any page specific titles.
Search for any <img src=""/> references to determine the images that will be downloaded by the user. Calculate the total bytes consumed by the actual images.
Combine the size of the modified HTML and the size of the images to determine the page overhead size. Round this value up or add additional padding to ensure that this overhead size represents all pages that can be generated.

The link size is how many bytes the markup consumes to generate a link such as <a href=""></a><br/>. This value is used to help calculate how many bytes are consumed for adding the link markup, the link target URL, and the link title. The default values for both properties were calculated from the page source generated for I-mode devices.