This element allows you to define conditions which can be used to dynamically change the installer, e.g. the panels shown, the variables set, files parsed, files executed and much more. When you define a condition it will get a type and an id. The id has to be unique. Conditions can be referenced based on this id (e.g. with the RefCondition).
There are several built-in types of conditions. At the time of writing this, Izpack has the following built-in types:
Condition |
Function |
Usage |
---|---|---|
VariableCondition |
based on the value of a certain variable |
|
PackSelectionCondition |
based on a pack selected for installation |
|
JavaCondition |
based on a static java field or method |
|
CompareNumericsCondition |
based on the comparison of a certain variable with a given value and operator |
|
RefCondition |
based on another condition |
|
There are also boolean types to combine more than one condition:
AndCondition |
both conditions have to be true |
OrCondition |
only one of both conditions has to be true |
XOrCondition |
one condition has to be true, the other one has to be false |
NotCondition |
the condition has to be false |
When you define a set of conditions, you just have to write as many <condition> tags as you like. A condition can take the following attributes:
Attribute |
Usage |
---|---|
|
the type of the condition. For built-in types, this is the lowercase portion of the condition class name without condition appended (variable,packselection,java, ...). Custom condition types should be referenced by the full qualified class name, e.g. de.dr.rules.MyCoolCondition. |
|
the id of the condition. This will be used to refer to this conditions in other elements |
The condition element can have several child elements depending on the type of this conditions. E.g. the VariableCondition has a name and value child element to specify, which variable should have a certain value to fullfil this condition.
This is an example which defines four conditions, two VariableConditions, a JavaCondition and a AndCondition which will refer to two of the first conditions.
<conditions> <condition type="variable" id="standardinstallation"> <name>setup.type</name> <value>standard</value> </condition> <condition type="variable" id="expertinstallation"> <name>setup.type</name> <value>expert</value> </condition> <condition type="java" id="installonwindows"> <java> <class>com.izforge.izpack.util.OsVersion</class> <field>IS_WINDOWS</field> </java> <returnvalue type="boolean">true</returnvalue> </condition> <condition type="and" id="standardinstallation.onwindows"> <condition type="ref" refid="standardinstallation"/> <condition type="ref" refid="installonwindows" /> </condition> </conditions>
Note, from IzPack 3.11 on normally, you don't have to define the compound conditions because you can use a simple expression language. The language has the following operators:
|
an operator for the Andcondition |
|
an operator for the OrCondition |
{{ |
an operator for the XOrCondition |
|
an operator for the NotCondition |
These simple expressions DO NOT follow the usual boolean logic with precedence rules. Instead, they are evaluated left to right in a simple way.
Thus, !conditionA+conditionB+!conditionC
DOES NOT equal (!conditionA) && conditionB && (!conditionC)
, but equals !(conditionA && (conditionB && !(conditionC)))
.
So you should definecomplex conditions using the xml structure.
More types of conditions can be defined by inheriting com.izforge.izpack.Condition class.
Built-in conditions
A number of built-in condition IDs are available for you.
Name |
Condition |
---|---|
izpack.windowsinstall |
The OS is (any) Windows |
izpack.windowsinstall.xp |
The OS is Windows XP |
izpack.windowsinstall.2003 |
The OS is Windows Server 2003 |
izpack.windowsinstall.vista |
The OS is Windows Vista |
izpack.windowsinstall.7 |
The OS is Windows 7 |
izpack.macinstall |
The OS is Mac OS X |
izpack.linuxinstall |
The OS is a Linux variant |
izpack.solarisinstall |
The OS is a Solaris variant |
izpack.solarisinstall.x86 |
The OS is a Solaris x86 variant |
izpack.solarisinstall.sparc |
The OS is a Solaris sparc variant |