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Example of Ant's uptodate Task
Example of Ant's uptodate taskI've had some difficulty getting ant's uptodate task working for me, so decided to come up with a "bare bones" example to demonstrate how it works.
'Uptodate' ExampleFirst of all, here's the example:
<project default="runtest"> <target name="init"> <touch file="old.txt"/> <sleep seconds="2"/> <touch file="new.txt"/> </target> <target name="check.new.newer"> <uptodate targetfile="new.txt" srcfile="old.txt" property="new.newer"/> </target> <target name="check.old.newer"> <uptodate targetfile="old.txt" srcfile="new.txt" property="old.newer"/> </target> <target name="is.old.newer" if="old.newer"> <echo message="old is newer than new"/> </target> <target name="is.new.newer" if="new.newer"> <echo message="new is newer than old"/> </target> <target name="runtest" depends="init, check.old.newer, check.new.newer, is.old.newer, is.new.newer"> <echo message="done"/> </target> </project>
Description of TargetsThe ant script contains the following six targets:
How It WorksI hope it is clear to you what is intended - the files are first created, then checked against each other using the uptodate task to see which is newer, and finally a message (or messages) is printed out according to the conditional targets
Sample OutputWhen the script is run (by typing ant) the following output is produced:
C:\uptodate-test>ant Buildfile: build.xml init: check.old.newer: check.new.newer: is.old.newer: is.new.newer: [echo] new is newer than old runtest: [echo] done BUILD SUCCESSFUL Total time: 2 secondsThis is exactly what we would hope to see - the file
SummaryThis is a good example because it demonstrates the setting, and not setting, of properties by the uptodate task, as well as the conditional execution of tasks based on whether properties have been set. The structure shown can form a basis for more complex scripts that use uptodate in conjunction with other tasks to perform conditional compilation or conditional distribution of code.