Types of Merge

This section explains the types of merge available to combine the display profile documents.

Overview

Display profile uses the following three types of merges to determine how to combine display profile documents:

replace

All the display profile objects defined in the higher priority document completely override the ones defined at the lower one. If the object does not exist in the lower priority document, it is added to the merge result (the object replaces the value in the merge results).

remove

The named object is removed from the merge up to this point (the object is removed from the merge results). It no longer exists in the display profile (but it can be re-introduced by another document to be merged). It can be redefined by a higher priority document.

fuse

The object from the lower priority document is combined with one from the higher priority document (the object is merged with the value in the merge results).

The exact meaning of each merge type depends on the display profile object they are applied to.

For channels and providers, fuse has special meaning. The channels themselves are not actually fused together. Rather, fuse indicates that the channel’s or provider’s properties should be combined. The replace semantic replaces the entire channel or provider, including all properties. The remove semantic removes the entire channel or provider from the merge up to that point.

The display profile <DisplayProfile> root node can also have merge semantics. The replace semantic means that all the DP objects defined in the higher priority document completely override the ones defined at the lower one. All merges up to that point are negated and the higher priority document is used as the new base for merging. The remove semantic indicates that all merge results up to the point of this document are to be discarded. The merge begins with the next display profile document found in the sorted set. As with channels and providers, the fuse semantic means that the contained objects (channels and providers) should be combined.

Atomic display profile properties (those that cannot contain other properties) cannot use the fuse semantic. This includes the String, Integer, Boolean, and Reference properties.

The set of properties for a channel consists of the channel’s properties plus the channel’s provider’s properties plus the channel’s parent’s properties, and so on. You can think of this total set of properties as the channel’s single document properties. An implication of document merging is that the total set of properties for a document consists of the set union of the channel’s single document properties for all documents in the user’s merge set.

Examples

This section provides examples for merge types such as remove, replace, and fuse.

Remove Example

This example uses the merge type remove to modify a container’s selected channel list.

The following example code shows how the merge sets of all users can consist of an organizational level document that contains the following display profile fragment.

<Container name="JSPTableContainer" provider="JSPTableContainerProvider" merge="fuse">
    <Properties> ... </Properties>
    <Available> ... </Available>
    <Selected merge="fuse">
        <Reference value="UnixTipoftheDay"/>
    </Selected>
</Container>

The “unix tip of the day” describes ways to use UNIX. It is likely that users that belong to the admin role would not find this channel helpful. To remove this channel from everyone with the admin role, define the TemplateTableContainer channel in the admin role document as follows:

<Container name="JSPTableContainer" provider="JSPTableContainerProvider" merge="fuse">
    <Properties> ... </Properties>
    <Available> ... </Available>
    <Selected merge="fuse">
        <Reference value="Outages"/>
        <Reference value="SolarisAdmin"/>
        <Reference value="AdminTipoftheDay"/>
        <Reference value="UnixTipoftheDay" merge="remove"/>
    </Selected>
</Container>

The preceding sample snippet causes the <Reference value="UnixTipoftheDay"> to be removed from the admin role display profile.

Replace Example

This example uses the merge type replace to remove channel from all users’ display.

The following example shows how for a particular container, a role admin can ignore all of the channels defined in the organization level. The organization definition resembles the following:

<Container name=...>
    ...
    ...
    <Selected>
        <Reference name="X"/>
        <Reference name="Y"/>
        <Reference name="Z"/>
    </Selected>
</Container>

Because the role admin does not want any of the users under that role to have the X, Y, or Z channels, the container is defined as follows:

<Container name=...>
    ...
    ...
    <Selected merge="replace">
        <Reference name="A"/>
        <Reference name="B"/>
        <Reference name="C"/>
    </Selected>
</Container>

The selected list in the role document’s container replaces the selected list in the organization document’s container.

Fuse Example

This example uses the merge type fuse to create role-based channel list.

Use the fuse merge semantic to combine non-atomic display profile objects. These objects include Collection and the available or selected channel lists. Here, fuse indicates that all the properties contained in the non-atomic property should also be merged. Using fuse in this way enables the final non-atomic property presented to the user to be build up from various documents.

The following example display profile documents are for a user who belongs to the admin, employee, and movieFreak roles. The selected channels for the user appear at the end.

Example 17–1 Display Profile for the Admin Role

<Container name="JSPTableContainer" provider="JSPTableContainerProvider" merge="fuse">
    <Properties> ... </Properties>
    <Available> ... </Available>
    <Selected merge="fuse">
        <Reference value="Outages"/>
        <Reference value="SolarisAdmin"/>
        <Reference value="AdminTipoftheDay"/>
    </Selected>
</Container>

Display Profile for the Employee Role

<Container name="JSPTableContainer" provider="JSPTableContainerProvider" merge="fuse">
    <Properties> ... </Properties>
    <Available> ... </Available>
    <Selected merge="fuse">
        <Reference value="Benefits"/>
        <Reference value="EmployeeNews"/>
    </Selected>
</Container>

Display Profile for the movieFreak Role

<Container name="JSPTableContainer" provider="JSPTableContainerProvider" merge="fuse">
    <Properties> ... </Properties>
    <Available> ... </Available>
    <Selected merge="fuse">
        <Reference value="NewMoviesReleases"/>
        <Reference value="MovieShowTimes"/>
    </Selected>
</Container>

The resultant list of selected channels for the user is as follows, with the available channel list ordered in the same way that the merging was applied, from lower to higher priority:

<Container name="JSPTableContainer" provider="JSPTableContainerProvider" merge="fuse">
    <Properties> ... </Properties>
    <Available> ... </Available>
    <Selected merge="fuse">
        <Reference value="Outages"/>
        <Reference value="SolarisAdmin"/>
        <Reference value="AdminTipoftheDay"/>
        <Reference value="Benefits"/>
        <Reference value="EmployeeNews"/>
        <Reference value="NewMoviesReleases"/>
        <Reference value="MovieShowTimes"/>
    </Selected>
</Container>