Date: 2004-02-28T21:28:08 Editor: 218.214.49.176 <> Wiki: Ant Wiki Page: NewAntFeaturesInDetail/PresetDef URL: http://wiki.apache.org/ant/NewAntFeaturesInDetail/PresetDef
no comment Change Log: ------------------------------------------------------------------------------ @@ -1,54 +1,82 @@ -[http://ant.apache.org/manual-1.6beta/CoreTasks/presetdef.html the task's manual page] +[http://ant.apache.org/manual/CoreTasks/presetdef.html the task's manual page] If you want a version of <ant> with the logical default of inheritall="false", here it is -{{{ -{{{ <presetdef name="better-ant"> }}} -{{{ <ant inheritall="false"/> }}} -{{{ </presetdef> }}} - }}} +{{{ + <presetdef name="better-ant"> + <ant inheritall="false"/> + </presetdef> +}}} wherever you use <better-ant>, it will behave exactly like the <ant> task but with a different default value. You can also define child elements. Say you want all your <javac> tasks to compile against a set of jars living in <code>/our/jar/repository/</code>, you could define -{{{ <presetdef name="my-javac"> }}} -{{{ <javac> }}} -{{{ <classpath> }}} -{{{ <fileset dir="/our/jar/repository/" includes="*.jar"/> }}} -{{{ </classpath> }}} -{{{ </javac> }}} -{{{ </presetdef> }}} +{{{ + <presetdef name="my-javac"> + <javac> + <classpath> + <fileset dir="/our/jar/repository/" includes="*.jar"/> + </classpath> + </javac> + </presetdef> +}}} and use <my-javac> wherever you'd use <javac> instead. It is interesting to note that both <code>presetdef</code> and <code>macrodef</code> dynamically define a task that can then be invoked as any other. Properly declared, the resulting tasks can be used interchangeably. Here is a simple example, in which the <code>filter</code> target will echo a message either to the console or to a file depending on whether the property <code>destfile</code> has been set: -{{{ -{{{ <target name="-tocon" unless="destfile"> }}} -{{{ <macrodef name="myecho"> }}} -{{{ <attribute name="message" /> }}} -{{{ <sequential> }}} -{{{ <echo taskname="myecho" }}} -{{{ message="Echoing a message to the console:" /> }}} -{{{ <echo taskname="myecho" message="@{message}" /> }}} -{{{ </sequential> }}} -{{{ </macrodef> }}} -{{{ </target> }}} -{{{ }}} -{{{ <target name="-tofile" if="destfile"> }}} -{{{ <presetdef name="myecho"> }}} -{{{ <echo file="${destfile}" /> }}} -{{{ </presetdef> }}} -{{{ </target> }}} -{{{ }}} -{{{ <target name="filter" depends="-tocon,-tofile"> }}} -{{{ }}} -{{{ <loadfile srcFile="${srcfile}" property="message"> }}} -{{{ <filterchain refid="myfilter" /> }}} -{{{ </loadfile> }}} -{{{ }}} -{{{ <myecho message="${message}" /> }}} -{{{ </target> }}} - }}} +{{{ + <target name="-tocon" unless="destfile"> + <macrodef name="myecho"> + <attribute name="message" /> + <sequential> + <echo taskname="myecho" + message="Echoing a message to the console:" /> + <echo taskname="myecho" message="@{message}" /> + </sequential> + </macrodef> + </target> + + <target name="-tofile" if="destfile"> + <presetdef name="myecho"> + <echo file="${destfile}" /> + </presetdef> + </target> + + <target name="filter" depends="-tocon,-tofile"> + + <loadfile srcFile="${srcfile}" property="message"> + <filterchain refid="myfilter" /> + </loadfile> + + <myecho message="${message}" /> + </target> +}}} + + +Another current use for <presetdef> is to provide a +work-around for a bug with the JDK 1.5beta1 javac compiler. +The compiler accepts target="1.1" but for some reason +this does not work unless one sets source="1.3" as well. +As this is a temporary issue one does not want to modify +the build script much. This can be achieved as follows: + +{{{ + <available property="jdk1.5+" classname="java.util.concurrent.Callable"/> + + <target name="check-1.5" if="jdk1.5+"> + <presetdef name="javac"> + <javac source="1.3"/> + </presetdef> + </target> + + <target name="init" depends="check-1.5"> + .... + </target> +}}} + +This will make a new javac task which will call the current +javac task with the source option set to 1.3. +It will also whine that one is overwritting the javac task. --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
