How to invoke the preprocessor « Slashdev Support Forum

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How to invoke the preprocessor

(13 posts) (2 voices)

Started 11 months ago by abell@safenet-inc.com
Latest reply from jiggak

Tags:

invoke preprocessor

abell@safenet-inc.com
Member

I downloaded then javapp.zip file, extracted and have the jar.
I also have a verysimple javac HelloWorls.java ready to test.
I can not find exactly how to use this wonderful tool - I am not using ANT at the moment. Can anyone point me to a list of instructions on what to do to invoke the preprocessor from the command line?
Thanks,
Adam

Posted 11 months ago #
abell@safenet-inc.com
Member

I think I just need how to load the xml definition files that has the preprocessing info and defines and the syntax for the input and output java files

Posted 11 months ago #
jiggak
Key Master

I'm afraid there is currently no way to invoke this from the command line without using Ant. You can find some sample Ant scripts here.

Posted 11 months ago #
abell@safenet-inc.com
Member

OK, I built a simple ant build.xml file and inserted the referenced code from the slashdev website (At end of this post), but Get an error - Not sure what I am missing here.
I can call any just fine and compile java directly - just failing to successfully preprocess
Any input would be greatly appreciated.
Adam

preprocess:
BUILD FAILED
C:\FOUO_SC650\java\build.xml:21: 'HelloWorld.java', line 5, char 6: Token not recognised in state 'ifcond'

complete build.xml file
<project name="HelloWorld" basedir="." default="main">

<property name="src.dir" value="src"/>

<property name="build.dir" value="build"/>
<property name="classes.dir" value="${build.dir}/classes"/>
<property name="jar.dir" value="${build.dir}/jar"/>

<property name="main-class" value="HelloWorld"/>

<target name="clean">
<delete dir="${build.dir}"/>
</target>

<taskdef resource="javapp-defs.xml" />
<property name="os_version" value="4.2" />

<target name="preprocess">
<javapp destdir="build\staging" prefix="//#">
<fileset dir="src" includes="**/*.java" />
<property name="PROJ1" value="SC650" />
</javapp>
</target>

<target name="compile">
<mkdir dir="${classes.dir}"/>
<javac srcdir="${src.dir}" destdir="${classes.dir}"/>
</target>

<target name="jar" depends="compile">
<mkdir dir="${jar.dir}"/>
<jar destfile="${jar.dir}/${ant.project.name}.jar" basedir="${classes.dir}">
<manifest>
<attribute name="Main-Class" value="${main-class}"/>
</manifest>
</jar>
</target>

<target name="run" depends="jar">
<java jar="${jar.dir}/${ant.project.name}.jar" fork="true"/>
</target>

<target name="clean-build" depends="clean,jar"/>

<target name="main" depends="clean,run"/>

</project>
<project name="HelloWorld" basedir="." default="main">

<property name="src.dir" value="src"/>

<property name="build.dir" value="build"/>
<property name="classes.dir" value="${build.dir}/classes"/>
<property name="jar.dir" value="${build.dir}/jar"/>

<property name="main-class" value="HelloWorld"/>

<target name="clean">
<delete dir="${build.dir}"/>
</target>

<taskdef resource="javapp-defs.xml" />
<property name="os_version" value="4.2" />

<target name="preprocess">
<javapp destdir="build\staging" prefix="//#">
<fileset dir="src" includes="**/*.java" />
<property name="PROJ1" value="SC650" />
</javapp>
</target>

<target name="compile">
<mkdir dir="${classes.dir}"/>
<javac srcdir="${src.dir}" destdir="${classes.dir}"/>
</target>

<target name="jar" depends="compile">
<mkdir dir="${jar.dir}"/>
<jar destfile="${jar.dir}/${ant.project.name}.jar" basedir="${classes.dir}">
<manifest>
<attribute name="Main-Class" value="${main-class}"/>
</manifest>
</jar>
</target>

<target name="run" depends="jar">
<java jar="${jar.dir}/${ant.project.name}.jar" fork="true"/>
</target>

<target name="clean-build" depends="clean,jar"/>

<target name="main" depends="clean,run"/>

</project>

Posted 11 months ago #
jiggak
Key Master

Can you post your .java file as well?

Posted 11 months ago #
abell@safenet-inc.com
Member

Here you go

public class HelloWorld
{
public static void main(String args[])
{
//#if defined(PROJ1) <<fails right here
System.out.println("Hello Project 1: ${PROJ1}");
//#else
System.out.println("Hello Project 2: ${PROJ2}");
//#endif
}
}

Posted 11 months ago #
abell@safenet-inc.com
Member

I also added this to supress an ant warning: includeantruntime="false"
and the dependancy for preprocess

<target name="compile" depends="preprocess">
<mkdir dir="${classes.dir}"/>
<javac srcdir="${src.dir}" destdir="${classes.dir}" includeantruntime="false"/>
</target>

Posted 11 months ago #

Strange. I don't seem to have the same problem in my tests. I did however get an error due to the PROJ2 property being undefined. Here is my test files:

# build.xml

<project default="preprocess">
   <taskdef resource="javapp-defs.xml" />

   <target name="preprocess">
      <javapp destdir="staging" prefix="//#">
         <fileset dir="src" includes="**/*.java" />
         <property name="PROJ1" value="SC650" />
         <property name="PROJ2" value="SC750" />
      </javapp>
   </target>
</project>

# HelloWorld.java

public class HelloWorld
{
   public static void main(String args[])
   {
      //#if defined(PROJ1)
      System.out.println("Hello Project 1: ${PROJ1}");
      //#else
      System.out.println("Hello Project 2: ${PROJ2}");
      //#endif
   }
}

Posted 11 months ago #

abell@safenet-inc.com
Member

Success - the fundamental problem was the //#ifdef, this does not seemed to be supported. I changed it to //#if defined(PROJ1) and that works
This was an assumption on my part - I'll read the syntax doc a little closer.

One oddity:
If I defined PROJ1 and PROJ2 in build.xml - the preprocess works, PROJ1 is printed out

If I defined ONLY PROJ1 - it fails, stating: property 'PROJ2' not defined

If I ONLY define PROJ2 - it works, PROJ2 is printed out

Am I missing something here - It seems the code would be VERY dependant on how the
"if defined() is used/ordered and how the properties are declared.

If I defined only PROJ1, I would expect the PROJ2 to be preprocessed out and no error to be thrown?

Thanks for the help. I appreciate it.
Adam

Posted 11 months ago #
abell@safenet-inc.com
Member

I found another oddity - perhaps you could comment on.

If I change the property definitions in ant's build.xml file, this does not cause a new preprocess to occur, I believe because the src files did not change. That it turn does not cause a recompile of the files.
The result is the build does not match the required definitions.

If I clean and and run again, I get what I expected.

Is there a way to force the preprocess to occurs based on the change of the build.xml file? - This may be more of an ant question than javapp question.

Thanks,
Adam

Posted 11 months ago #
jiggak
Key Master
The behavior with PROJ1 and PROJ2 properties is most certainly a bug (or more appropriately something I didn't consider closely enough while developing javapp).

Regarding the property changes in the build.xml file not causing a re-compile, yes I think this is really better left up to the ant script itself. For example use the <uptodate> task to check if build related files are newer than pre-processor output.
```
<target name="clean" if="buildxml_is_newer">
   <delete dir="staging" />
</target>

<target name="preprocess" depends="check-build-files,clean">
   ...
</target>

<target name="check-build-files">
   <uptodate srcfile="build.xml" property="buildxml_is_newer">
      <srcfiles dir="staging" includes="**/*" />
   </uptodate>
</target>
```
Posted 11 months ago #
abell@safenet-inc.com
Member

Great, Thanks
I resolved the PROJ1 and PROJ2 by defining a seperate control property ACTIVE_PROJECT.
I also discovered that using the #if ${prop} == xxx, that xxx must be a numeric value.
if you make changes in the future, a string based comparison would be useful too.

ACTIVE_PROJECT=MyProject vs. ACTIVE_PROJECT=1234

Thanks for the help, I have a working ant script and controls now

Posted 11 months ago #
jiggak
Key Master

If you surround the literal "xxx" with double quotes string comparison is (*should*) be performed.

Also to overcome the issue with a property being undefined you don't even need to give it a value in Ant. Something like ACTIVE_PROJECT= would suffice.

There should be section in the README regarding the types of comparisons available and the syntax for the literal values inside expressions.

Posted 11 months ago #

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