Develop Reference

Custom manifest added multiple times in -post-jar in a common dependency

I have a multi-module native Netbeans Java EE project. In it I have a Java Class Library project that is used by multiple other projects which in turn are packaged into the root .ear project.
I'm adding the "build timestamp" and the "build user" attributes to a custom manifest using the library's build.xml:
<target name="-post-jar">
<jar destfile="${dist.jar}" update="true">
<manifest>
When I "clean and build" the root project, each project that refers the library calls:
<ant antfile="${call.script}" target="jar">
And my -post-jar target is called multiple times. This wouldn't be a problem, but sometimes the second invocation of the <jar> task fails with Unable to rename old file (probably due to Netbeans scanning the files in background, but I can't tell for sure).
There are repeating pairs of Building jar and Updating jar messages in Ant's output. However, if I remove my -post-jar target, the second invocation of the jar target does nothing, because it thinks that the jar is up to date and I see only one Building jar message.
How do I mark the updated jar up to date, so the second invocation of the jar target does nothing?
There's a github repo that demonstrates the problem.

I haven't found a way to not re-generate the manifest every time, but I found a way to make the generated file look the same as the zipped file (and we know that the <jar> task doesn't repack when the contents are the same).
Instead of updating the zipped manifest in -post-jar I now update the source file in -pre-jar. This way the final version of the manifest is zipped and since its contents don't change during build, subsequent <jar> invocations update nothing.
It worth mentioning that before adding the attributes Main-Class, Profile, etc. the build-impl.xml of Netbeans creates an empy manifest template, if the user doesn't provide a valid path in the manifest.file= property. The addition happens after -pre-jar, however the existence of the user-provided manifest is checked much earlier, during the init target and the result is saved to the manifest.available property.
My manifest template is not a static file. It contains the "build timestamp" and the "build user" attributes. Therefore the file doesn't exist during the init target, so I had to add the following line at the beginning of my build.xml:
<property name="manifest.available" value="true"/><!-- It will be available by the time we need it -->
Secondly, manifest.file still has to be set and I set it in project.properties (there's no UI for that setting yet and I wonder how it would behave in the presence of the variable in path)
manifest.file=${build.dir}/manifest.tmp
Next, I overwrite the manifest template in the -pre-jar target:
<tstamp>
<format property="current.time" pattern="HH:mm:ss" locale="de,DE"/>
</tstamp>
<target name="-pre-jar" >
<manifest file="${manifest.file}">
<attribute name="MyApp-built-time" value="${current.time}"/>
<attribute name="MyApp-built-by" value="${user.name}"/>
</manifest>
After that, the new problem became obvious: the timestamp was different for each invocation of
<ant antfile="mylib/build.xml" target="jar">
in the multi-module project and Ant had to repack the jar with the new timestamp in the manifest. I solved this by defining the timestamp property in every project's build.xml. Although the properties are not inherited due to inheritall="false", Netbeans allows for overcoming that:
<property name="transfer.current.time" value="${current.time}"/>
This mechanism is broken in Java EE projects, but the workaround is simple:
<presetdef name="ant">
<!-- workaround transfer.* not working in Java EE projects -->
<ant>
<propertyset>
<propertyref prefix="transfer."/>
<mapper from="transfer.*" to="*" type="glob"/>
</propertyset>
</ant>
</presetdef>

Apache Ant {Compile javac srcdir} does not exist

I am new to apache ant and I am currently working on an apache Ant project. I Just started out, imported the project into workspace and tried to run the build.xml. I added all the libraries that come with the original project to the build path. I am having the following problem. Please someone else wrote the code and I am supposed to improve it. The directories this is all about exist in the project directory.
BUILD FAILED
C:\workspace\MyApp\build.xml:83: srcdir "C:\workspace\MyApp\${compile.javac.srcdir}" does not exist!
The error code is referencing the following part of the build.xml file
<target name="compile.default" depends="init">
<javac fork="yes" srcdir="${compile.javac.srcdir}" destdir="${compile.javac.destdir}" includes="${compile.javac.include}" excludes="${compile.javac.exclude}" classpath="${compile.javac.classpath}" debug="${compile.javac.debug}" optimize="${compile.javac.optimize}" deprecation="${compile.javac.deprecation}" verbose="${compile.javac.verbose}">
</javac>
<copy todir="${compile.javac.destdir}">
<fileset dir="${compile.javac.srcdir}" includes="${compile.copy.include}" excludes="${compile.copy.exclude}"/>
</copy>
</target>
<target name="compile" depends="init,compile.default" description="Compile all java source">
</target>
<!--+++++++++++++++-->
<!-- lib target(s) -->
<!--+++++++++++++++-->
<target name="lib.default" depends="init,compile">
<xmlbean schema="config/schemas/validate/1.0/validate.xsd" destfile="lib/glx-beans.jar" classpath="lib/xbean.jar:lib/jsr173_1.0_api.jar" />
<jar jarfile="${lib.filename}">
<fileset dir="${lib.srcdir}" excludes="${lib.exclude}" />
</jar>
</target>
<target name="lib" depends="init,compile,lib.default" description="Create all Project Libraries">
</target>
Would you please tell me what I am missing?

The ${compile.javac.srcdir} isn't defined. There are a few possibilities:
This is defined not in the build.xml, but in some sort of properties file. See if you have something like <property file="..."/> in your build script. My recommendation is to have all properties defined in the build.xml file, and use a properties file to override those settings. This way, the only build file that a developer needs in the build.xml file and doesn't have to worry about setting up a separate build.porperties file.
This is defined in the build.xml file under a particular task, but you forgot to say that your target where you use thisis dependent upon this task.
One of the things you can do is use the -d parameter when running Ant. I run the following command when running Ant with the -d parameter:
$ and -d 2>&1 | tee ant.out
I can then look at ant.out and see if somehow I didn't define that particular property. Maybe I had the wrong capitalization or misspelled the property name. For example, it's very likely I'll define the property as copmile.javac.srcdir because I don't know how to spell. Looking at the -d output can quickly point these types of errors out.
By the way, you shouldn't have all of your tasks dependent upon init since they're dependent upon compile.default anyway:
<target name="compile.default" depends="init">
....
</target>
<target name="compile" depends="compile.default">
....
</target>
<target name="lib" depends="compile,lib.default">
....
</target>
If I run the target lib, it will see compile is dependent upon compile.default which is dependent upon init. Thus, your build will run init, then compile.default, then compile, then 'lib.defaultand finallylib`.
If the init task is just setting up properties, you can do that outside of any task. Then, these properties will be setup before any task is executed. This way, they're not forgotten. If your init is also creating directories, you may want to move those <mkdir/> tasks in front of the task where that directory is used. For example, you may want to make the destdir uses in javac before the <javac/> task.
I find assigning default properties outside of any task, and creating directories before they are needed to simplify the build.xml. Plus, you're not creating a whole flock of unused directories if the user is merely compiling and not packaging the jar/war/etc.

copy a file in ant based on condition

I have to copy a file if a property is set in ant target, but I always get an error for this code:
<condition property="component.is.x">
<equals arg1="${COMPONENT_ID}" arg2="x" />
</condition>
<target name="copyschemaparamsfile" if="sql.file.present" >
<if>
<equals arg1="${component.is.x}" arg2="true" />
<then>
<copy file="${in.root}/schema/${COMPONENT_ID}-schema.sql"
tofile="${tmp.dir}/${COMPONENT_ID}/x/schema/schema.sql"
failonerror="false" />
</then>
<else>
<copy file="${inf.root}/schema/${COMPONENT_ID}-schema.sql"
tofile="${tmp.dir}/${COMPONENT_ID}/${COMPONENT_ID}/schema/schema.sql" failonerror="false" />
</else>
</if>
</target>
Error is:
Ant could not find the task or a class this task relies upon.
This is common and has a number of causes; the usual
solutions are to read the manual pages then download and
install needed JAR files, or fix the build file:
- You have misspelt 'if'.
Fix: check your spelling.
- The task needs an external JAR file to execute
and this is not found at the right place in the classpath.
Fix: check the documentation for dependencies.
Fix: declare the task.
- The task is an Ant optional task and the JAR file and/or libraries
implementing the functionality were not found at the time you
yourself built your installation of Ant from the Ant sources.
Fix: Look in the ANT_HOME/lib for the 'ant-' JAR corresponding to the
task and make sure it contains more than merely a META-INF/MANIFEST.MF.
If all it contains is the manifest, then rebuild Ant with the needed
libraries present in ${ant.home}/lib/optional/ , or alternatively,
download a pre-built release version from apache.org
- The build file was written for a later version of Ant
Fix: upgrade to at least the latest release version of Ant
- The task is not an Ant core or optional task
and needs to be declared using <taskdef>.
- You are attempting to use a task defined using
<presetdef> or <macrodef> but have spelt wrong or not
defined it at the point of use
Remember that for JAR files to be visible to Ant tasks implemented
in ANT_HOME/lib, the files must be in the same directory or on the
classpath
I am always getting above error when I execute. Can someone please suggest how to check for a parameter and copy from one directory to other within an ant target?

Ant <if/> is part of Ant-Contrib. To use, follow the directions on the Ant-Contrib Tasks installation page:
(1) Copy ant-contrib-0.3.jar to the lib directory of your Ant
installation. If you want to use one of the tasks in your own project,
add the lines
<taskdef resource="net/sf/antcontrib/antcontrib.properties"/>
to your build file.
(2) Keep ant-contrib-0.3.jar in a separate location. You now have to
tell Ant explicitly where to find it (say in /usr/share/java/lib):
<taskdef resource="net/sf/antcontrib/antcontrib.properties">
<classpath>
<pathelement location="/usr/share/java/lib/ant-contrib-0.3.jar"/>
</classpath>
</taskdef>

Running ant file from its own directory

I have a big ANT script that I use to build-up my environment: total-build.xml.
It calls a bunch of little build.xml files.
However, each of these build.xml files is designed to run in its directory.
For example:
(Project)Build: total-build.xml
(Project)A: build.xml
(Project)B: build.xml
(Project)C: build.xml
total-build.xml looks a bit like:
<ant file="A\build.xml"/>
<ant file="B\build.xml"/>
<ant file="C\build.xml"/>
A\build.xml looks like this:
<copy dir="src" todir="dest"/>
That is, it contains relative paths assumed to be under A. In the example, I expect src == A\src.
I don't want to write absolute paths, as they make things inelegant.
So is there a way to tell ant to run the build.xml file from its own directory.
Suprisingly, I found nothing about this issue using google.

You could use the base dir property for the project tag of each build, like this:
<project name="main" default="help" basedir="..">
...
</project>
and use all relative paths.

Stopping only a portion of build script

I have run into a problem regarding the build script. Presently I have a main build.xml file that calls each internal build.xml files from a directory. The internal build.xml has 2 stages to execute wherein at the end i get a jar file.
My requirement is that if anything foes wrong in the 1st step of the internal build.xml file, i should not get the jar file, but the main build should continue execution and go to the next internal build.xml file.
In the internal build.xml based on some condition i want to stop that internal build.What changes should i make in my code to stop that particular build?
Thanks in advance.

Set failonerror="false" on your subant tasks you're using to call the other build files.

If you can afford to add ant-contrib to your build, then it is easy. In your main task, do:
<target name="xxx">
<var name="firstStepOK" value="true"/>
<trycatch>
<try>
<!-- call first sub build -->
</try>
<catch>
<var name="firstStepOK" value="false"/>
</catch>
</trycatch>
<!-- call second sub build, pass value of firstStepOK -->
</target>
Unfortunately, ant-contrib has never made it into ant proper, which is a pity. It contains very useful tasks.