Does a target get noted as "not run" if all of its tasks decide they are up to date?
On Tuesday, February 18, 2003, at 01:38 PM, Dale Anson wrote:
I think the problem/perception boils down to the difference between a target and a task. Targets have no concept of "out of date". Target can have dependencies, but the dependencies are targets that again have no concept of "out of date". Tasks (including the property task) can understand "out of date". The javac task is a good example in that it only makes the compiler compile out of date source files. However, tasks are not required to have any sense of "out of date". For example, the echo task blindly prints a message to the output stream everytime it is called, it doesn't know or care whether it already printed the message. You can make a target "know" about being out of date through use of properties and the if/unless target attributes. This isn't automatic, you have to do the set up yourself. From your examples, if you tell Ant to run target B, Ant will run target B and target B will attempt to execute all of the tasks it contains every single time it is called (depending, of course, on the result of the if/unless tests). Note that target B only takes non-zero time to run if the tasks it contains take non-zero time to run, and again, the determination that a particular task in a target should execute is performed by the task, not the target.
Dale Anson
Timothy Wall wrote:
The goal is not "run A before B" (although that may be a requirement). The goal is "only run B if it is out of date". Ant by default runs (almost) everything all the time.
If B takes nonzero time to run, I *only* want it to run if B is "out of date". Normally, a target would be considered out of date if
a) any of its "depends" is out of date (and thus gets run)
b) some other prerequisites are not satisfied (i.e. .java is newer than .class, or the .jar file is not yet built)
Some examples of standard conditional execution:
idl parsing/code generation: generate .java code only if .idl files have been modified
jar file: only run jar if the class files it depends on have been regenerated
java compiler: only compile if .java is newer than .class
The last is the only thing that I've seen ant handle automatically, although I seem to have a knack for configuring things such that it recompiles everything every time.
On a complex project, typically you'll have many smaller targets with internal dependencies (and some with prerequisit targets as dependencies) and several overall targets that primarily consist of prerequisite target dependencies (a jar file or shared library, for instance).
On Tuesday, February 18, 2003, at 10:23 AM, [EMAIL PROTECTED] wrote:
When you use <target name="B" depends="A"/> the Ant framework will invoke A before B. Why setting a property?BTW the "onlyif" is <target if="propertyname"/> There is a unless="propertyname", too. Jan Mat�rne--------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]--------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
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