Peter,
sounds great. How does your implementation using threadLocal
works when going across <ant> or <antcall>? Just curious.
Jose Alberto
> -----Original Message-----
> From: peter reilly [mailto:peter.reilly@corvil.com]
> Sent: 20 October 2003 09:59
> To: Ant Developers List
> Subject: Re: Macrodef and parallel in a recursive situation
>
>
> I have written the code to support local properties.
> While I was doing this, I realized that the attributes
> of a macrodef could/should be local properties as well,
> removing some of the issues seen last week (use of attribute
> in a bsf script and support of parallel/recursive).
>
> The following shows it in using a new task called local.
>
> <project name="local">
> <property name="prop1" value="a global value"/>
> <target name="test1">
> <local name="prop1" value="a local value"/>
> <echo>prop1 is "${prop1}"</echo>
> </target>
> <target name="test2" depends="test1">
> <echo>prop1 is "${prop1}"</echo>
> </target>
> </project>
>
> This ant test2 generates the following:
>
> test1:
> prop1 is "a local value"
>
> test2:
> prop1 is "a global value"
>
> Each taskcontainer sets up a new local scope:
>
> <target name="sequential">
> <local name="prop2" value="in target"/>
> <sequential>
> <local name="prop2" value="in sequential"/>
> <echo>prop2 is "${prop2}"</echo>
> </sequential>
> <echo>prop2 is "${prop2}"</echo>
> </target>
>
> will generate the following:
> sequential:
> prop2 is "in sequential"
> prop2 is "in target"
>
> The value part of <local> is optional, and the local
> property may be set by a subsequent <property>, <property>
> will only set it if the value is not set.
>
> <target name="notset">
> <local name="prop3"/>
> <echo>prop3 is "${prop3}"</echo>
> <property name="prop3" value="is set"/>
> <property name="prop3" value="is set again"/>
> <echo>prop3 is "${prop3}"</echo>
> </target>
>
> will generate the following:
> notset:
> prop3 is "${prop3}"
> prop3 is "is set"
>
> prop3 is still a local variable and will not be seen outside
> the target.
>
> The local properties are thread local so the following works
> as expected:
> <target name="parallel">
> <local name="prop4"/>
> <parallel>
> <sequential>
> <property name="prop4" value="thread1"/>
> <echo>t1: prop4 is "${prop4}"</echo>
> </sequential>
> <sequential>
> <property name="prop4" value="thread2"/>
> <echo>t2: prop4 is "${prop4}"</echo>
> </sequential>
> <sequential>
> <property name="prop4" value="thread3"/>
> <echo>t3: prop4 is "${prop4}"</echo>
> </sequential>
> </parallel>
> </target>
>
> parallel:
> t2: prop4 is "thread2"
> t1: prop4 is "thread1"
> t3: prop4 is "thread3"
>
> Use with macrodef.
> -----------------
>
> Attributes may now be implemented as local properties, which
> means that they will be seen as normal properties by ant
> tasks - including script.
>
> <target name="macro">
> <macrodef name="callscript">
> <attribute name="x"/>
> <sequential>
> <script language="beanshell">
> System.out.println("x is '" +
> project.getProperty("x") + "'");
> </script>
> </sequential>
> </macrodef>
>
> <callscript x="this is x"/>
> </target>
>
> will generate:
> macro:
> x is 'this is x'
>
> Macrodef does not do the attribute substitutions so the following
> <target name="macro2">
> <macrodef name="callscript">
> <attribute name="x"/>
> <sequential>
> <script language="beanshell">
> System.out.println("x is '${x}'");
> </script>
> </sequential>
> </macrodef>
>
> <callscript x="this is x"/>
> </target>
> will generate:
> macro2:
> x is '${x}'
> as <script/> does not do property expansion.
>
> A variation of the recurive macrodef last week may be done by:
> <target name="recur">
> <macrodef name="recur">
> <attribute name="thread"/>
> <attribute name="current"/>
> <sequential>
> <antcontrib:if>
> <equals arg1="0" arg2="${current}"/>
> <then>
> <echo message="Thread: ${thread} done"/>
> </then>
> <else>
> <antcontrib:math
> datatype = "int"
> operand1 = "${current}"
> operation = "-"
> operand2 = "1"
> result = "current"
> />
> <echo message = "T: ${thread}, C: ${current}" />
> <sleep seconds="1"/>
> <recur current = "${current}" thread = "${thread}" />
> </else>
> </antcontrib:if>
> </sequential>
> </macrodef>
>
> <parallel>
> <recur thread="1" current="5"/>
> <recur thread="2" current="6"/>
> <recur thread="3" current="2"/>
> </parallel>
> </target>
>
> The output is:
> recur:
> T: 3, C: 1
> T: 1, C: 4
> T: 2, C: 5
> T: 3, C: 0
> T: 1, C: 3
> T: 2, C: 4
> Thread: 3 done
> T: 1, C: 2
> T: 2, C: 3
> T: 1, C: 1
> T: 2, C: 2
> T: 1, C: 0
> T: 2, C: 1
> Thread: 1 done
> T: 2, C: 0
> Thread: 2 done
>
>
>
> I realize that it is late in the day to get this
> into ant1.6, but I think that it will make macrodef
> much more usefull and easy to port current antcalls.
>
> The changes are quite small (mostly to PropertyHelper).
>
> Peter
>
> On Saturday 18 October 2003 16:22, Jose Alberto Fernandez wrote:
> > > From: peter reilly [mailto:peter.reilly@corvil.com]
> > >
> > > I think that we may need a thread local variable to
> > > handle parallel.
> > >
> > > This would mean some deep messing with the Property handling.
> >
> > I do not see how thread locals would help here. I guess the
> question
> > is whether tasks in parallel should be able to modify the global
> > properties in the frame, or should the changes be local to the
> > parallel branch (and somehow joined at the end of execution).
> >
> > That would mean each parallel computation branch is independent. I
> > guess I am suggesting the second type of implementation
> proposed for
> > <local-property> to be used instead for <parallel>. I think
> that would
> > be a much more efficient way to do it. So here is how it would work:
> >
> > 1) Add new attribute independent (default false) to <parallel>.
> >
> > 2) When independent is true, each thread will use a cloned project
> > frame for its execution. So all properties and reference
> manipulation
> > will be independent of each other. When the thread ends, any new
> > properties added in the cloned frame, will be added to the original
> > parent frame, following the common rules for setting
> properties. Which
> > means that the first thread that finish will win on setting the
> > property, if another thread ends later and tries to set the same
> > variable, it will loose. For references, we need to copy
> any changes
> > and due to its semantics all threads will contribute as they end.
> >
> > 3) When independent is false, parallel works as today (for backward
> > compatibility), all threads see each others changes.
> >
> > This rules seem easy programable without big changes to CORE.
> >
> > I would still like having <local-property> which could be
> implemented
> > as per the first description proposed below.
> >
> > Jose Alberto
> >
> > > Peter
> > >
> > > On Friday 17 October 2003 17:57, Jose Alberto Fernandez wrote:
> > > > > From: peter reilly [mailto:peter.reilly@corvil.com]
> > > > >
> > > > > I would rather have Jose's idea of a <local-property/> task.
> > > > >
> > > > > This could be used outside of macrodef.
> > > > >
> > > > > The only problem is the implementation.
> > > >
> > > > Indeed, there is an easy implementation but will not solve
> > >
> > > the case of
> > >
> > > > <parallel>, because the local definition would really be a
> > >
> > > temporary
> > >
> > > > global one:
> > > >
> > > > public class LocalProperty extends Sequential {
> > > > private String property;
> > > > private String oldValue;
> > > >
> > > > public setName(String i_property){property = i_property;}
> > > >
> > > > public void execute() {
> > > > if (property == null) throw new BuildException("name
> > >
> > > attribute is
> > >
> > > > mandatory");
> > > > try {
> > > > oldValue = getProject().getProperty(property);
> > > > getProject().setProperty(property, null); // This
> may need
> > > > changes to core
> > > > super.execute();
> > > > }
> > > > finally {
> > > > // This is using the deprecated setProperty method
> > > > // that actually changes the properties even if set
> > > > getProject().setProperty(property, oldValue);
> > > > }
> > > > }
> > > > }
> > > >
> > > > Here we just change the property value on the project
> > >
> > > frame, for the
> > >
> > > > duration of the task. And put the old value back before
> we leave.
> > > >
> > > > The problem with this simple implementation is that all the
> > >
> > > parallel
> > >
> > > > branches will see the change, which is exactly what we were
> > >
> > > trying to
> > >
> > > > avoid. To do it
> > > > right, we would need to create a new execution frame that
> > >
> > > would be use
> > >
> > > > in the
> > > > "super" call.
> > > >
> > > > But if we do that (which is like what <ant> or
> <antcall> do), what
> > > > happens if the user defines properties other than the
> > >
> > > local-property
> > >
> > > > inside the code?
> > > > Somehow, we would need to find them and propagate them back
> > >
> > > to the frame
> > >
> > > > above
> > > > upon exit.
> > > >
> > > > <local-property name="x">
> > > > <property name="y" value="myY"/>
> > > > <local-property>
> > > > <echo message="${y}"/>
> > > >
> > > > [echo] myY
> > > >
> > > > Doable, but not that easy anymore.
> > > >
> > > > What do you guys think?
> > > >
> > > > Jose Alberto
> > > >
> > > > > Peter
> >
> >
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