18.1. Using linkType to implement link navigation

18.1. Using `linkType` to implement link navigation
	18. linkType

18.1. Using `linkType` to implement link navigation

The user can navigate from a link source to the link target and the other way round by using the items of menu Select → Link and also the equivalent toolbar buttons.

These menu items and these toolbar buttons are always operative whether a linkType confirguration element has been defined or not. The reason is, when no linkType element is found in a configuration file, XXE will behave as if the following one was defined:

<linkType>
  <class>com.xmlmind.xmleditapp.linktype.IDLinkType</class>
</linkType>

Note that during the link navigation, XXE may have to open the document containing the destination. When this is the case, the user is prompted to confirm that she/he really wants to open this document and whether she/he wants to open it in read-only mode or in normal, read-write, mode.

This works because command XXE.edit in XMLmind XML Editor - Commands also allows to select a link target or a link source. In order to do that, XXE.edit is passed an URL ending with a proprietary XPointer leveraging the link type of the destination. Examples of such proprietary XPointers:

Open file book.xml and select the element having "introduction" as its anchor name. The searched anchor "introduction" belongs to the link type called "default".
```
book.xml#xmlns(l=urn:xxe:link)l:anchor(introduction)
```
Same but the searched anchor "978-3-16-148410-0" belongs to the link type called "ISBN".
```
book.xml#xmlns(l=urn:xxe:link)l:anchor(978-3-16-148410-0%20ISBN)
```
Open file introduction.dita and select the element acting as a link pointing to "concepts.dita#concepts/collection". The searched anchor "concepts/collection" belongs to the link type called "default".
```
introduction.dita#xmlns(l=urn:xxe:link)l:link(concepts.dita%20concepts/collection)
```
Open file chapter2.xml and select the element acting as a link pointing to "reference". The searched anchor "reference" belongs to the link type called "default".
```
chapter2.xml#xmlns(l=urn:xxe:link)l:link(%20reference)
```


18. linkType		18.2. Using `linkType` to implement link validation