Dynamic Installer Requirements - <dynamicinstallerrequirements>

This feature was introduced Introduced in IzPack 5.0.The main goal was , the <dynamicinstallerrequirements>  element is used to enhance the "classic" installer requirement of IzPack, which has been checked checking that IzPack does at the early beginning of an installation process to stop it, . This stops the installation unless a certain condition is met.

With this enhancementthe dynamicinstallerrequirements element, you will be able to can check a certain set of installer requirements conditions on each panel change, using a panel data validator for dynamic installer requirements.

Example:

...

to check if the required conditions are met.

<dynamicinstallerrequirements>
  <installerrequirement severity="error"
                        condition="this.condition.must.not.happen"
                        messageid="this.condition.must.not.happen.translation.id"/>
  <installerrequirement severity="error"
                        condition="this.condition.may.happen"
                        messageid="this.condition.may.happen.translation.id"/>
  ...
</dynamicinstallerrequirements>

If a condition applies, a messagebox is shown with the appropriate content from translation. Depending on the value of severity attribute the installation might be continued or is aborted:

• "error"
  The messagebox is shown and the installation aborts.
• "warning"
  The messagebox is shown and the installation can continue after the OK button is pressed.

A more detailed example:

<condition type="variable" id="isNew">
  <name>previous.version</name>
  <value>XX.XX.XX</value>
</condition>
<condition type="not" id="isUpgrade">
  <condition type="ref" refid="isNew"/>
</condition>
...
<dynamicinstallerrequirements>
  <installerrequirement condition="isUpgrade" severity="warning" messageid="not.an.upgrade.warning.message"/>
</dynamicinstallerrequirements>
...
<panels>
  <panel classname="HelloPanel"/>
  <panel classname="TargetPanel">
    <validator classname="DynamicInstallerRequirementValidator"/>
  </panel>
  <panel classname="PacksPanel"/>
  <panel classname="InstallPanel"/>
  <panel classname="FinishPanel"/>
</panels>

Each On each panel the with a DynamicInstallerRequirementValidator is assigned to will be evaluated according to the requirements given as nested elements in <dynamicinstallerrequirements>.

installerrequirement attributes:

...

<installerrequirement> - Attributes

severity

...

...

...

condition

messageid