Writing Installation XML Files

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What You Need

Your editor

In order to write your XML installation files, you just need a plain text editor. Of course it's always easier to work with color coded text, so you might rather want to work with a text editor having such a feature. Here is a list of free editors that work well :

If you are a developer and tend to write your own patches, extension or features to IzPack sources, or, if you wish to debug your compilation, installation and uninstallation, we recommend these IDE:

For the first one, JetBrains has granted us an Open Source License. All project members can ask the Licence Key to one of the project manager.

The other ones are well know open source projects (Just like us :-)). We provide a tutorial on how to develop/debug IzPack using Eclipse in the chapter ''Getting Started > How to develop and debug IpPack using Eclipse''

Writing XML

Though you might not know much about XML, you have certainly heard about it. If you know XML you can skip this subsection as we will briefly present how to use XML.

XML is a markup language, really close to HTML. If you've ever worked with HTML the transition will be fast. However there are a few little things to know. The markups used in XML have the following form : <markup>. Each markup has to be closed somewhere with its ending tag : </markup>. Each tag can contain text and other markups. If a markup does not contain anything, it is just reported once : <markup/>. A markup can contain attributes like : <markup attr1="123" attr2="hello !"/>. Here is a sample of a valid XML structure :

<chapter title="Chapter 1">
  <section name="Introduction">
    This is the text of the paragraph number 1. It is available
    for the very low
    price of <price currency="dollar">1 000 000</price>.
  <section name="xxx">

You should be aware of the following common mistakes :

  • markups are case sensitive : <markup> is different from <Markup>.
  • you must close the markups in the same order as you create them : <m1><m2>(...)</m2></m1> is right but `` <m1><m2>(...)</m1></m2>`` is not.

Also, an XML file must start with the following header : <?xml version="1.0" encoding="iso-8859-1 standalone="yes" ?>. The only thing you should modify is the encoding (put here the one your text editor saves your files to). The `` standalone`` attribute is not very important for us.

This (brief !) introduction to XML was just meant to enable you to write your installation specification. For a better introduction there are plenty of books and articles/tutorials dealing with XML on the Internet, in book stores, in magazines and so on.

Variable Substitution

During the installation process IzPack can substitute variables in various places with real values. Obvious targets for variable substitution are resource files and launch scripts, however you will notice many more places where it is more powerful to use variables rather then hard coded values. Wherever variables can be used it will be explained in the documentation.

There are three types of variables:

You define your own variables in the installation XML file with the <variable> tag. How to do this is explained in detail later in this chapter.

Please note that when using variables they must always appear with a '$' sign as the first character, even though they are not defined this way.

The Built-In Variables

The following variables are built-in :

Environment Variables

Environment variables can be accessed via the syntax ${ENV[variable]}. The curly braces are mandatory. Note that variable names are case-sensitive and usually in UPPER CASE.

Example: To get the value of the OS environment variable "CATALINA_HOME", use ${ENV[CATALINA_HOME]}.

Dynamic Variables

Dynamic variables can be defined in the installation XML with the <variable> tag inside the <dynamicvariables> element. The value of dynamic variables will be evaluated every time a panel is switched, i.e. between the panels. Dynamic variables can have a condition which will be evaluated first. If it's true, the value would be assigned, otherwise nothing happens to the variable.

As and addition to normal variables, the value of a variable can either be defined by using the value attribute or by using a child element called value.

Example1: To change a certain directory based on user input, use the following <variable name="test" value="/test/${USER_INPUT}" condition="hasuserinput" /> The condition has userinput has to be specified in the condition section of installation XML.

Example2: To comment out something in a xml file if a certain pack with id mycoolfeature is not activated, you could use "two" dynamic variables to create a xml comment or not.

<variable name="XML_Comment_Start" condition="!izpack.selected.mycoolfeature">
<variable name="XML_Comment_End" condition="!izpack.selected.mycoolfeature">
<variable name="XML_Comment_Start" value="" condition="izpack.selected.mycoolfeature" />
<variable name="XML_Comment_End" value="" condition="izpack.selected.mycoolfeature" />

The condition izpack.selected.mycoolfeature is generated automatically when a pack with id mycoolfeature was specified. You would now use ${XML_Comment_Start} and ${XML_Comment_End} in a file which should be parsed.

Parse Types

Parse types apply only when replacing variables in text files. At places where it might be necessary to specify a parse type, the documentation will mention this. Depending on the parse type, IzPack will handle special cases -such as escaping control characters- correctly. The following parse types are available:

Unless using braces to surround variable's name (${variable} or %{variable}}, the variable name can contain following characters: letters, digits, dots, dashes (-), underbars (_). Example: $this.is-my_variable

If you want to have two variables separated by character that is allowed to appear in variable name, for example: $major-version.$minor-version, then you must use braces, and the above example should look like: ${major-version}.${minor-version}.

The IzPack Elements

When writing your installer XML files, it's a good idea to have a look at the iZPACK installation DTD.

The Root Element <installation>

The root element of an installation is <installation>. It takes one required attribute : version. The attribute defines the version of the XML file layout and is used by the compiler to identify if it is compatible with the XML file. This should be set to 1.0 for the moment.

The Information Element <info>

This element is used to specify some general information for the installer. It contains the following elements :

  • <appname> : the application name
  • <appversion> : the application version
  • <appsubpath> : the subpath for the default of the installation path. A variable substitution and a maskable slash-backslash conversion will be done. If this tag is not defined, the application name will be used instead.
  • <url> : the application official website url
  • <authors> : specifies the author(s) of the application. It must contain at least one <author> element whose attributes are :
    • name : the author's name
    • email : the author's email
  • <uninstaller> : specifies whether to create an uninstaller after installation, and which name to use for it. This tag has the write attribute, with default value `` yes``. If this tag is not specified, the uninstaller will still be written. The name attribute can be used to change the default name of the generated uninstaller, i.e. `` uninstaller.jar``. The condition attribute can be used to specify a condition which has to be fullfilled for creating the uninstaller. The path attribute can be used to define the destination path where the uninstaller is written to, i.e. ${INSTALL_PATH}/Uninstaller.
  • <javaversion> : specifies the minimum version of Java required to install your program. Values can be 1.2, 1.2.2, 1.4, etc. The test is a lexical comparison against the java.version System property on the install machine.
  • <requiresjdk>: (yes or no) specifies wether a JDK is required for the software to be installed and executed. If not, then the user will be informed and given the option to still proceed with the installation process or not.
  • <webdir> : Causes a ''web installer'' to be created, and specifies the URL packages are retrieved from at install time. The content of the tag must be a properly formed URL.
  • <summarylogfilepath> : specifies the path for the logfile of the SummaryLoggerInstallerListener.
  • <writeinstallationinformation> : (yes or no) specifies if the file .installinformation should be written which includes the information about installed packs. The default if not specified is yes.
  • <pack200/>: adding this element will cause every JAR file that you will add to your packs to be compressed using Pack200 (see http://java.sun.com/j2se/1.5.0/docs/guide/deployment/deployment-guide/pack200.html). As a special exception, signed JARs are not compressed using Pack200, as it would invalidate the signatures. This makes the compilation process a little bit longer, but it usually results in drasticaly smaller installer files. The decompression is relatively fast. Please note that Pack200 compression is destructive, i.e., after decompression a JAR won't be identical to its original version (yet the code in the class files remains semantically equivalent).
  • <run-privileged/>: adding this element will make the installer attempt to launch itself with administrator permissions. Il also supports a condition attribute to reference a condition id so that the elevation is not always attempted (e.g., you may want to activate it only for Windows Vista). This is not supported on all platforms, in which case a message will be provided to the user before continuing the installation. You can disable this feature for the uninstaller by specifying uninstaller="yes" as an attribute. Only use this feature if you really need to be an administrator as part of your installation process.

Here is an example of a typical <info> section :

  <appname>Super extractor</appname>
  <appversion>2.1 beta 6</appversion>
    <author name="John John Doo" email="jjd@jjd-mail.com"/>
    <author name="El Goyo" email="goyoman@mymail.org"/>

Here is one where the privileges elevation is attempted on Windows Vista and Mac OS X :

        <author email="" name="Julien Ponge (project founder)"/>
        <author email="" name="The fantastic IzPack developers and contributors"/>
    <run-privileged condition="izpack.windowsinstall.vista|izpack.macinstall"/>

The Packaging Element <packaging>

This element allows to specify packaging options. If not specified, the default will be to create an all in one installer. This element will usually be used to create an installer which spans over multiple volumes, e.g. the output will be two CDs. The packaging-element contains the following elements:

  • <packager> : specifies options used by the packager. The packager tag has the class attribute, which specifys the class to use for packaging. Currently two implementations are available (com.izforge.izpack.compiler.Packager, com.izforge.izpack.compiler.MultiVolumePackager). The packager-element can contain the <options> element which can have different attributes for the different implementations of packagers. For the MultiVolumePackager, it can have the following attributes:

    • volumesize: the size of the volumes
    • firstvolumefreespace: free space on the first volume used for the installer jar and additional resources like readme-files etc.
  • <unpacker> : specifies which unpacker class should be used. Currently there are two unpacker implementations

    (com.izforge.izpack.compiler.UnPacker, com.izforge.izpack.compiler.MultiVolumeUnPacker).

Here's an example how to specify an installer which will create multiple volumes. In this example the volumes shall be CDs with 650 megabytes. There will be an additional free space of 150 megabytes on the first volume. This will result in the creation of an installer.jar and multiple installer.pak* files. The installer.jar plus installer.pak plus the additional resources have to be copied on the first volume, each installer.pak.<number> on several volumes.

  <packager class="com.izforge.izpack.compiler.MultiVolumePackager">
              <!-- 650 MB volumes, 150 MB space on the first volume -->
      <options volumesize="681574400" firstvolumefreespace="157286400"/>
  <unpacker class="com.izforge.izpack.installer.MultiVolumeUnpacker" />

The Variables Element <variables>

This element allows you to define variables for the variables substitution system. Some variables are built-in, such as $INSTALL_PATH (which is the installation path chosen by the user). When you define a set of variables, you just have to place as many <variable> tags in the file as needed. If you define a variable named VERSION you need to type $VERSION in the files to parse. The variable substitutor will then replace it with the correct value. One <variable> tag take the following attributes :

  • name : the variable name
  • value : the variable value

Here's a sample <variables> section :

  <variable name="app-version" value="1.4"/>
  <variable name="released-on" value="08/03/2002"/>

Here's a precise sample on how to use desktopshortcutcheckboxenabled and InstallerFrame.logfilePath variables:

  <variable name="InstallerFrame.logfilePath" value="$INSTALL_PATH
    <!-- This means that the log name will be My-install and that
  it will be stored at the root of the installation. -->
    <!-- Any path is fine. If value is set to "Default" then
  "$INSTALL_PATH/uninstall/install.log" is used. -->
    <!-- And if variable isn't defined then no log is written. -->
  <variable name="desktopshortcutcheckboxenabled" value="true"/>
    <!-- This automatically checks the "Create Desktop Shortcuts"
  button. Default value is "False". -->

The dynamic Variables Element <dynamicvariables>

This element allows you to define dynamic variables for the variables substitution system. In contrast to the static <variables, dynamic variables will be evaluated every time, a panel switch is done.

When you define a set of variables, you just have to place as many <variable> tags in the file as needed. Normally you would use the condition attribute to specify, when a certain value will be set.

One <variable> tag take the following attributes :

  • name : the variable name
  • value : the variable value
  • condition : a condition for this variable, which has to be true to set the value

Here's a sample <dynamicvariables> section :

  <variable name="app-version" value="1.4" condition="mycondition1" />
  <variable name="app-version" value="1.4b" condition="!mycondition1" />
  <variable name="released-on" value="08/03/2002" />

The Conditions Element <conditions>

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:

  • VariableCondition: a condition based on the value of a certain variable
  • PackSelectionCondition: a condition based on a pack selected for installation
  • JavaCondition: a condition based on a static java field or method.
  • CompareNumericsCondition: a condition based on the comparison of a certain variable with a given value and operator.

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:

  • type: 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.

  • id: 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.

   <condition type="variable" id="standardinstallation">
   <condition type="variable" id="expertinstallation">
   <condition type="java" id="installonwindows">
             <returnvalue type="boolean">true</returnvalue>
       <condition type="and" id="standardinstallation.onwindows">
             <condition type="ref" refid="standardinstallation"/>
             <condition type="ref" refid="installonwindows" />

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

Neverthless if you define really complex conditions it's much easier to define them 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 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

The Installer Requirements Element <installerrequirements>

This element allows to specify requirements for running the installation. This will be done based on conditions defined in the conditons section.

An installer requirement consists of a condition and a message which will be shown if the condition is not fulfilled. If so, the installer will show the message and exit after that.

  • installerrequirement: specifies a single installer requirement. You can define an unlimited number of them.

Installerrequirements have the following attributes: - condition: an id of a condition defined in the conditions section - message: a message text or a langpack key defining which message should be shown before exiting the installer in case of a missing requirement.

   <installerrequirement conditon="installonwindows" message="This installer could only be run on Windows operating systems."/>

The GUI Preferences Element <guiprefs>

This element allows you to set the behavior of your installer GUI. This information will not have any effect on the command-line installers that will be available in future versions of IzPack. The arguments to specify are :

  • resizable : takes yes or no and indicates whether the window size can be changed or not.
  • width : sets the initial window width
  • height : sets the initial window height.

Here's a sample :

<guiprefs resizable="no" width="800" height="600"/>

Starting from IzPack 3.6, the look and feel can be specified in this section on a per-OS basis. For instance you can use the native look and feels on Win32 and OS X but use a third-party one on Unix-like platforms. To do that, you have to add some children to the guiprefs tag:

  • laf: the tag that specifies a look and feel. It has a name parameter that defines the look and feel name.
  • Each laf element needs at least one os tag, specified like in the other parts of the specification that support this tag.
  • Like you can add os elements, you can add any number of param elements to customize a look and feel. A param elements has two attribues: name and `` value``.

The available look and feels are:

  • Kunststoff: kunststoff
  • Liquid: liquid
  • Metouia: metouia
  • JGoodies Looks: looks
  • Substance: substance

If you don't specify a look and feel for a particular operating system, then the default native one will be used: Windows on Windows, Aqua on Mac OS X and Metal on the Unix-like variants.

The Liquid Look and Feel supports the following parameters:

  • decorate.frames: yes means that it will render the frames in Liquid style
  • decorate.dialogs: yes means that it will render the dialogs in Liquid style

The JGoodies Looks look and feel can be specified by using the variant parameters. The values can be one of:

  • windows: use the Windows look
  • plastic: use the basic Plastic look
  • plastic3D: use the Plastic 3D look
  • plasticXP: use the Plastic XP look (default).

Here is a small sample:

<guiprefs height="600" resizable="yes" width="800">
    <laf name="metouia">
        <os family="unix" />
    <laf name="looks">
        <os family="windows" />
        <param name="variant" value="extwin" />

The Substance look and feel toned-down themes can be specified using the variant parameter, with the value being one of: business, business- blue, business-black, creme, sahara, moderate, officesilver. We have reduced the choice to the toned-down themes since they are the only ones to actually look decent (the other families colors are way too saturated). Please consult https://substance.dev.java.net/docs/skins/toneddown.html for a gallery of the different toned-down themes.

Starting from IzPack 3.7, some characteristics can be customized with the <modifier> tag. There is a separate description in the Advanced Features chapter paragraph Modifying the GUI.

The Localization Element <locale>

This element is used to specify the language packs (langpacks) that you want to use for your installer. You must set one <langpack> markup per language. This markup takes the `` iso3`` parameter which specifies the iso3 language code.

Here's a sample :

  <langpack iso3="eng"/>
  <langpack iso3="fra"/>
  <langpack iso3="spa"/>

The supported ISO3 codes are :

ISO3 code Language
cat Catalunyan
chn Chinese
cze Czech
dan Danish
glg Galician
deu German
eng English
eus Basque
fin Finnish
fra French
hun Hungarian
ita Italian
jpn Japanese
mys Malaysian
ned Nederlands
nor Norwegian
pol Polnish
por Portuguese (Brazilian)
prt Portuguese (European)
rom Romanian
rus Russian
scg Serbian
spa Spanish
svk Slovakian
swe Swedish
ukr Ukrainian

The Resources Element <resources>

Several panels, such as the license panel and the shortcut panel, require additional data to perform their task. This data is supplied in the form of resources. This section describes how to specify them. Take a look at each panel description to see if it might need any resources. Currently, no checks are made to ensure resources needed by any panel have been included. The `` <resources>`` element is not required, and no <res> elements are required within. The <resources> element is the only element besides the <packs> element that is taken into consideration in referenced pack-files (see `<packs> element`_ for more info)

You have to set one <res> markup for each resource. Here are the attributes to specify :

  • src : the path to the resource file which can be named freely of course (for instance my-picture.jpg).
  • id : the resource id, depending on the needs of a particular panel
  • parse : takes yes or no (default is no) - used to specify whether the resource must be parsed at the installer compilation time. For instance you could set the application version in a readme file used by InfoPanel.
  • type : specifies the parse type. This makes sense only for a text resource - the default is plain, other values are javaprop, xml, plain, java, shell, at, ant (Java properties file and XML files)
  • encoding : specifies the resource encoding if the receiver needs to know. This makes sense only for a text resource.

Here's a sample :

  <res id="InfoPanel.info" src="doc/readme.txt" parse="yes"/>
  <res id="LicencePanel.licence" src="legal/License.txt"/>

Please note that in general a resource id is unique. Thus if you define multiple resources with the same id the later definition (e.g. a resource defined in a referenced pack-file) will overwrite the previous definition. However there is an exception for packsLang.xml_xyz files (see Internationalization of the PacksPanel). If multiple packsLang-files were defined, all files will be merged into a single temporary file. This allows refpack files to provide their own internationalization-information.

The Panels Element <panels>

Here you tell the compiler which panels you want to use. They will appear in the installer in the order in which they are listed in your XML installation file. Take a look at the different panels in order to find the ones you need. The <panel> markup takes the following attributes:

  • classname: which is the classname of the panel.
  • id: an identifier for a panel which can be used e.g. for referencing in userinput panel definitions.
  • condition: an id of a condition which has to be fullfilled to show this panel
  • jar: jar file where the classes for this panel can be found. This attribute is optional. If it is empty (jar="") the classes for this panel must be murged using the <jar> tag.

Here is a sample :

    <panel classname="HelloPanel"/>
    <panel classname="LicencePanel"/>
    <panel classname="TargetPanel"/>
    <panel classname="InstallPanel"/>
    <panel classname="UserInputPanel" id="myuserinput" condition="pack2selected" />
    <panel classname="FinishPanel" jar="MyFinishPanel.jar"/>

The following sections describe the tags available for a <panel> section.

<help> - optional file for a help

The content of the help file is shown in a small window on the panel, when User clicks on the help button. The button is only shown, when a help in the language exists.

The <help> takes the following attributes :

  • iso3: iso3 representation of the language the help is written
  • src: path to the help file to display

Here's a sample :

<panel classname="HelloPanel">
  <help iso3="deu" src="HelloPanelHelp_deu.html" />
  <help iso3="eng" src="HelloPanelHelp_eng.html" />

<validator> - optional validation on idata

This validation is done, when going on for the next panel. It is also done in case of an automatic installation. The class must implement the interface com.izforge.izpack.installer.DataValidator.

The <validator> takes the following attributes :

  • classname: The class implementing com.izforge.izpack.installer.DataValidator

Here's a sample :

<panel classname="UserInputPanel" id="jdbc.connection.parameters">
  <validator classname="JdbcConnectionValidator" />

<actions> - optional actions for the panel

Here you can define multiple actions that are done during the lifetime of the panel. The class must implement the interface com.izforge.izpack.installer.PanelAction. The actions are also called during an automated installation.

The <actions> tag has no attributes but has <action> markups with the following attributes :

  • stage: The stage when the action should be triggered.

    Possible values are preconstruct, preactivate, prevalidate or postvalidate.

  • classname: The class implementing com.izforge.izpack.installer.PanelAction

Here's a sample :

<panel classname="UserInputPanel" id="jdbc.connection.parameters">
    <action stage="preconstruct" classname="ConnectionPreConstructAction" />
    <action stage="preactivate" classname="ConnectionPreActivateAction" />
    <action stage="prevalidate" classname="ConnectionPreVAlidateAction" />
    <action stage="postvalidate" classname="ConnectionPostValidateAction" />

The Packs Element <packs>

This is a crucial section as it is used to specify the files that need to be installed. The <packs> section consists of several <pack>, <refpack> and <refpackset> tags.

The <pack> takes the following attributes :

  • name: the pack name
  • required: takes yes or no and specifies whether the pack is optional or not.
  • os: optional attribute that lets you make the pack targeted to a specific operating system, for instance unix, mac and so on.
  • preselected: optional attribute that lets you choose whether the pack is by default selected for installation or not. Possible values are yes and no. A pack which is not preselected needs to be explicitly selected by the user during installation to get installed.
  • loose: can be used so that the files are not located in the installer Jar. The possible values are true or false, the default beeing false. The author of this feature needed to put his application on a CD so that the users could run it directly from this media. However, he also wanted to offer them the possibility to install the software localy. Enabling this feature will make IzPack take the files on disk instead of from the installer. Please make sure that your relative files paths are correct !
  • id: this attribute is used to give a unique id to the pack to be used for internationalization via packsLang.xml file.
  • packImgId: this attribute is used to reference a unique resource that represents the pack's image for the ImgPacksPanel. The resource should be defined in the <resources> element of the installation XML using the same value for the id attribute of the <res> element.
  • condition: an id of a condition which has to be fullfilled to install this package.
  • hidden: takes true or false and specifies whether the pack shall be shown in the packs panel. The bytes of such a hidden pack will be used to calculate the required space, but the pack itself won't be shown. A hidden pack can be selected conditionally. So you have to specify a condition to enable it for installation. The default for this attribute is false

The <refpack> takes only one attribute file, which contains the relative path (from the installation compiler) to an externally defined packs-definition. This external packs definition is a regular IzPack installation XML. However the only elements that are used from that XML file are the <packs> and the <resources> elements. This enables a model in which a single developer is responsible for maintaining the packs and resources (e.g. separate packsLang.xml_xyz files providing internationalization; see Internationalization of the PacksPanel) related to the development-package assigned to him. The main install XML references these xml-files to avoid synchronization efforts between the central installation XML and the developer-maintained installer XMLs.

The <refpackset> tag can be used in situations were there is no predefined set of <refpack> files, but a given directory should be scanned for <refpack> files to be included instead. This element takes the following parameters:

  • dir: the base directory for the refpackset (relative path)
  • includes: a pattern of files in <refpack> format that must be included

An example:

<refpackset dir="" includes="**/refpack.xml" />

Internationalization of the PacksPanel

In order to provide internationalization for the PacksPanel, so that your users can be presented with a different name and description for each language you support, you have to create a file named packsLang.xml_xyz where xyz is the ISO3 code of the language in lowercase. Please be aware that case is significant. This file has to be inserted in the resources section of `` install.xml`` with the id and src attributes set at the name of the file. The format of these files is identical with the distribution langpack files located at `` $IZPACK_HOME/bin/langpacks/installer``. For the name of the panel you just use the pack id as the txt id. For the description you use the pack id suffixed with .description.

An example:

    <res id="packsLang.xml_eng" src="i18n/myPacksLang.xml_eng"/>

The packsLang.xml_eng file:

    <str id="myApplication" txt="Main Application"/>
    <str id="myApplication.description" txt="A description of my main application"/>

The following sections describe the tags available for a <pack> section.

<description> - pack description

The contents of the <description> tag describe the pack contents. This description is displayed if the user highlights the pack during installation.

<depends> - pack dependencies

This can be used to make this pack selectable only to be installed only if some other is selected to be installed. The pack can depend on more than one by specifying more than one `` <depends>`` elements. Circular depedencies are not supported and the compiler reports an error if one occurs.

This tag takes the following attribute:

  • packname: The name of the pack that it depends on

<os> - OS restrictions

It is possible to restrict a panel to a certain list of operating systems. This tag takes the following attributes:

  • family: unix, windows or mac
  • name: the exact OS name (ie Windows, Linux, ...)
  • version: the exact OS version (see the JVM os.version property)
  • arch: the machine architecture (see the JVM os.arch property).


This feature can update an already installed package, therefore removing superfluous files after installation. Here's how this feature author (Tino Schwarze) described it on the IzPack development mailing-list:

> Each pack can now specify an <updatecheck> tag. It supports a subset of ant fileset syntax, e.g.:

  <include name="lib/**" />
  <exclude name="config/local/** />

> If the paths are relative, they will be matched relative to $INSTALL_PATH. Update checks are only enabled if at least one <include> is specified. See `` com.izforge.izpack.installer.Unpacker`` for details.

<file> - add files or directories

The <file> tag specifies a file (a directory is a file too) to include into the pack. It takes the following attributes:

  • src: the file location (relative path) - if this is a directory its content will be added recursively. It may contain previously defined static variables (see <variables>).
  • targetdir: the destination directory, could be something like $INSTALL_PATH/subdirX
  • os: can optionally specify a target operating system (unix, windows, mac) - this means that the file will only be installed on its target operating system
  • override: if true then if the file is already installed, it will be overwritten (use false otherwise). Alternative values: asktrue and askfalse - ask the user what to do and supply default value for non-interactive use. Another possible values is update. It means that the new file is only installed if it's modification time is newer than the modification time of the already existing file (note that this is not a reliable mechanism for updates - you cannot detect whether a file was altered after installation this way.) By default it is set to `` update``.
  • unpack: if true and the file is an archive then its content will be unpacked and added as individual files
  • condition: an id of a condition which has to be fullfilled to install this file


This tag can also be specified in order to pass additional data related to a file tag for customizing.

  • <key>: key to identify the data
  • <value>: value which can be used by a custom action

<singlefile> - add a single file

Specifies a single file to include. The difference to <file> is that this tag allows the file to be renamed, therefore it has a target attribute instead of `` targetdir``.

  • src: the file location (relative path). It may contain previously defined static variables (see <variables>).
  • target: the destination file name, could be something like $INSTALL_PATH/subdirX/fileY
  • os: can optionally specify a target operating system (unix, windows, mac) - this means that the file will only be installed on its target operating system
  • override: see <file> for description
  • condition: an id of a condition which has to be fullfilled to install this file

A <additionaldata> tag can also be specified for customizing.

<fileset>: add a fileset

The <fileset> tag allows files to be specified using the powerful Jakarta Ant set syntax. It takes the following parameters:

  • dir: the base directory for the fileset (relative path)
  • targetdir: the destination path, works like for <file>
  • casesensitive: optionally lets you specify if the names are case- sensitive or not - takes yes or no
  • defaultexcludes: optionally lets you specify if the default excludes will be used - takes yes or no.
  • os: specifies the operating system, works like for <file>
  • override: see <file> for description
  • includes: comma- or space-separated list of patterns of files that must be included; all files are included when omitted. This is an alternative for multiple include tags.
  • excludes: comma- or space-separated list of patterns of files that must be excluded; no files (except default excludes) are excluded when omitted. This is an alternative for multiple exclude tags.
  • condition: an id of a condition which has to be fullfilled to install the files in this fileset

You specify the files with <include> and <exclude> tags that take the name parameter to specify the Ant-like pattern :

  • ** : means any subdirectory
  • * : used as a wildcard.

Here are some examples of Ant patterns :

  • <include name="lib"/> : will include lib and the subdirectories of lib
  • <exclude name="**/*.java"/> : will exclude any file in any directory starting from the base path ending by .java
  • <include name="lib/*.jar"/> : will include all the files ending by .jar in lib
  • <exclude name="lib/**/*FOO*"/> : will exclude any file in any subdirectory starting from lib whose name contains FOO.

There area set of definitions that are excluded by default file-sets, just as in Ant. IzPack defaults to the Ant list of default excludes. There is currently no equivalent to the <defaultexcludes> task. Default excludes are:


A <additionaldata> tag can also be specified for customizing.

<parsable> - parse a file after installation

Files specified by <parsable> are parsed after installation and may have variables substituted.

  • targetfile : the file to parse, could be something like $INSTALL_PATH/bin/launch-script.sh A slash will be changed to the system dependant path separator (e.g. to a backslash on Windows) only if no backslash masks the slash.
  • type : specifies the type (same as for the resources) - the default is plain
  • encoding : specifies the file encoding
  • os: specifies the operating system, works like for <file>
  • condition: an id of a condition which has to be fullfilled to parse this file

<executable> - mark file executable or execute it

The <executable> tag is a very useful thing if you need to execute something during the installation process. It can also be used to set the executable flag on Unix-like systems. Here are the attributes :

  • targetfile : the file to run, could be something like $INSTALL_PATH/bin/launch-script.sh Slashes are handled special (see attribute targetfile of tag <parsable>).
  • class : If the executable is a jar file, this is the class to run for a JavaTM program
  • type : bin or jar (the default is bin)
  • stage : specifies when to launch : postinstall is just after the installation is done, never will never launch it (useful to set the +x flag on Unix). uninstall will launch the executable when the application is uninstalled. The executable is executed before any files are deleted. never is the default value.
  • failure : specifies what to do when an error occurs : abort will abort the installation process, ask (default) will ask the user what to do and warn will just tell the user that something is wrong
  • os: specifies the operating system, works like for <file>
  • keep : specifies whether the file will be kept after execution. The default is to delete the file after is has been executed. This can be changed by specifying keep="true".
  • condition: an id of a condition which has to be fullfilled to execute this file

A <args> tag can also be specified in order to pass arguments to the executable:

  • <arg>: passes the argument specified in the value attribute. Slashes are handled special (see attribute targetfile of tag <parsable>.

<os> - make a file OS-dependent

The <os> tag can be used inside the <file>, <fileset>, <singlefile>, <parsable>, <executable> tags to restrict it's effect to a specific operating system family, architecture or version using the following attributes:

  • family: unix, windows, mac to specify the operating system family
  • name: the operating system name
  • version: the operating system version
  • arch: the operating system architecture (for instance the Linux kernel can run on i386, sparc, and so on)

Here's an example installation file fragment:



    <pack name="Core" required="yes">


        <executable targetfile="$INSTALL_PATH/bin/compile" stage="never">
            <os family="unix"/>





The Native Element <native>

Use this if you want to use a feature that requires a native library. The native libraries are placed under bin/native/... There are 2 kinds of native libraries : the iZPACK libraries and the third-party ones. The IzPack libraries are located at bin/native/izpack, you can place your own libraries at `` bin/native/3rdparty``. It is possible to place a native library also into the uninstaller.

It is usable from CustomActions. If one or more are referenced for it, the needed support classes are automatically placed into the uninstaller. To place it only on operating systems for which they are build, it is possible to define an OS restriction. This restriction will only be performed for the uninstaller. The markup takes the following attributes :

  • type : izpack or 3rdparty
  • name : the library filename
  • stage: stage where to use the library (install|uninstall|both)
  • src : source directory where to find the library to build the installer

Note for developers: com.izforge.izpack.util.Librarian.loadLibrary() must be used to load custom native libraries, as it performs some housekeeping.

<os> - make a library OS-dependent

The <os> tag can be used to restrict the inclusion into the uninstaller to a specific operating system family, architecture or version. The inclusion into the installer will be always done.

Here's a sample :

<native type="izpack" name="ShellLink.dll">
    <os family="windows"/>

The Jar Merging Element <jar>

If you adapt iZPACK for your own needs, you might need to merge the content of another jar file into the jar installer. For instance, this could be a library that you need to merge. The <jar> markup allows you to merge the raw content of another jar file into the installer and the uninstaller. It is necessary that the paths in the jars are unique because only the contained files of the jar are added to the installer jar, not the jar file self. The attributes are:

  • src : the path at compile time
  • stage: stage where to use the contents of the additional jar file (install|uninstall|both)

A sample :

<jar src="../nicelibrary.jar"/>

XInclude-style constructs

The xi:include element is used to include xml or text documents in your configuration files.

The xi:include element can be used anywhere in pretty much any of the xml files used by IzPack. It is supported by the javax DocumentBuilder. It follows the XInclude recommandation produced by the W3C (http://www.w3.org/TR/xinclude/) and should be able to be used as decribed in that document.

To use the xi:include, you have to specify the namespace xmlns:xi="http://www.w3.org/2001/XInclude" in your xml.

If a logical error appear in an included file, the line number shown will indicate the xinclude element in the main xml file.

The xi:include element has the following attributes:

The location of the file to include. If this is a relative path (e.g. href='../bob.xml') then the file is resolved relative to the document that includes the xinclude element. The href element can be a remote url (e.g. href='http://example.com/file.txt') but this is not recommended.
Indicates that the included file should be treated as xml, forcing the included file to be parsed (which results in all xinclude elements in the included file to also be included), or as text which includes the specified file as a text node. It can have a value of 'xml' or 'text' and defaults to 'xml' if ommitted.
In case in parse="xml", you can use xpointer to get a part of the included xml. The details of the xpointer framework can be found http://www.w3.org/TR/2003/REC-xptr-framework-20030325/.
This is used when the parse attribute is 'text' to specify the character encoding of the included text document. It has no effect if parse is 'xml'.
Used if the href attribute specifies a url accessible via HTTP. The value of this attribute will be added as the accpet header on the HTTP request.

The fallback element

The xi:fallback element is used to provide a fallback if the xi:include element fails. It can be empty or can contain a valid xml. If it is empty then a failure to include the specified document is supressed. If it contains a xml then a failure to include the specified document causes the xml specified in the fallback is parsed (evaluating nested xinclude elements) and inserted into the document in its place.

For example the following use of xi:include

<?xml version="1.0" encoding="iso-8859-1" standalone="yes" ?>
<aaa xmlns:xi="http://www.w3.org/2001/XInclude">
  <xi:include href="does-not-exist.xml">

will result in

<?xml version="1.0" encoding="iso-8859-1" standalone="yes" ?>

if the file 'does-not-exist.xml' does indeed not exist.

The xfragment element

The xfragment element allows document fragments (xml documents without a single top level element) to be included. Simply use the xfragment as the top level element in the included document. It will be removed when the document is included.

e.g. If I want to use xi:include to include a file containing the following fragments:


I could use the xfragment element to enable it

<?xml version="1.0" encoding="iso-8859-1" standalone="yes" ?>

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