2.6.3.1. Navigation Data

The navigation data import strategy will be processed to the import mode level as the followings:

CONSERVE: If the navigation exists, leave it untouched. Otherwise, import data.
INSERT: Insert the missing description data, but add only new nodes. Other modifications remains untouched.
MERGE: Merge the description data, add missing nodes and update same name nodes.
OVERWRITE: Always destroy the previous data and recreate it.

In the GateIn navigation structure, each navigation can be referred to a tree which each node links to a page content. Each node contains some description data, such as label, icon, page reference, and more. Therefore, GateIn provides a way to insert or merge new data to the initiated navigation tree or a sub-tree.

The merge strategy performs the recursive comparison of child nodes between the existing persistent nodes of a navigation and the transient nodes provided by a descriptor:

Start with the root nodes (which is the effective root node or another node if the parent URI is specified).
Compare the set of child nodes and insert the missing nodes in the persistent nodes.
Proceed recursively for each child having the same name.

Let's see the example with two navigation nodes in each import mode. In this case, there are 2 navigation definitions:

<node-navigation>
  <page-nodes>
    <node>
      <name>foo</name>
      <icon>foo_icon_1</icon>
      <node>
        <name>juu</name>
        <icon>juu_icon</icon>
      </node>
    </node>
    <node>
      <name>daa</name>
      <icon>daa_icon</icon>
    </node>
  </page-nodes>
</node-navigation>

Navigation node tree hierarchy

<node-navigation>
  <page-nodes>
    <node>
      <name>foo</name>
      <icon>foo_icon_2</icon>
    </node>
    <node>
      <name>bar</name>
      <icon>bar_icon</icon>
    </node>
  </page-nodes>
</node-navigation>

Navigation node tree hierarchy

For example, the navigation1 is loaded before navigation2. The Navigation Importer processes on two navigation definitions, depending on the Import Mode defined in portal configuration.

Case 1: Import mode is CONSERVE.
With the CONSERVE mode, data are only imported when they do not exist. So, if the navigation has been created by the navigation1 definition, the navigation2 definition does not affect anything on it. We have the result as following
Case 2: Import mode is INSERT.
If a node does not exist, the importer will add new nodes to the navigation tree. You will see the following result:
Hereafter, the node 'bar' is added to the navigation tree, because it does not exist in the initiated data. Other nodes are kept in the import process.
Case 3: Import mode is MERGE.
The MERGE mode indicates that a new node is added to the navigation tree, and updates the node data (such node label and node icon in the example) if it exists.
Case 4: Import mode is OVERWRITE.
Everything will be destroyed and replaced with new data if the OVERWRITE mode is used.