Java Developer Guide/Using eant

Preparing sources for building with ant

Replacing removed bundled jars

There are some build systems that require jars to be in certain locations. Per Gentoo Java Packaging Policy and the previous section those jars have now been removed. They need to be replaced using symlinks to system jars to let the build system proceed without further modification. This is mostly a legacy way of doing things, as most build systems will look for jars on the classpath.

CODE Replacing removed bundled jar files with system

src_prepare() {
    default
    # change directory to where the jars you removed were located
    cd lib

    # needed at runtime not just build, will be on the package classpath in package.env
    java-pkg_jar-from jdom

}

Modify build system

There are times when you might need to modify the build system. If a project uses ant as a build system, there can be unwanted targets that are always called. Or targets that will download dependencies outside of portage. Other times there might be unwanted classes or resources on the classpath, or it is missing a classpath that will be set/added to the ebuild.

To avoid unwanted targets you can either remove them entirely from the build.xml file, or you can comment out the targets via XML comments, <!-- •••••• -->. This can be done via one or more patches and/or sed if minimal. Pay close attention to target dependencies, and dependent targets. At times bypassing one unwanted target can bypass other wanted targets. There are times you might need to change a target's dependencies rather than bypassing a target entirely.

Note
When you comment out targets or anything in xml via XML comments, <!-- •••••• -->, those comments will disappear when the xml file is passed through the xml-rewriter. It will remove any comments entirely. This can cause patches to fail if the patch is made after the xml-rewriter has modified the xml file. Make sure to always make patches and sed for raw untouched sources.

Compiling with ant

eant is a Gentoo wrapper around ant. One should never invoke ant directly in an ebuild but instead call eant.

CODE Using ant Global Variables

inherit java-pkg-2

...

	eant jar $(usev doc javadoc) \
		-Dant.build.javac.source="$(java-pkg_get-source)" \
		-Dant.build.javac.target="$(java-pkg_get-target)"

Typical examples using java-ant-2.eclass

FILE foo-1.0.ebuildExample of a Java ant ebuild

# Copyright 1999-2024 Gentoo Authors
# Distributed under the terms of the GNU General Public License v2

EAPI=8

# Tests require an existing running SQL server and 'junit.jar.file' property
JAVA_PKG_IUSE="doc examples source"

inherit java-pkg-2

DESCRIPTION="JDBC drivers with JNDI-bindable DataSources"
HOMEPAGE="https://www.mchange.com/projects/c3p0/"
SRC_URI="https://downloads.sourceforge.net/project/c3p0/c3p0-src/c3p0-${PV}/${P}.src.tgz"
S="${WORKDIR}/${P}.src"

LICENSE="|| ( EPL-1.0 LGPL-2.1 )"
SLOT="0"
KEYWORDS="~amd64 ~ppc64 ~x86 ~amd64-linux ~x86-linux"

CP_DEPEND="
	dev-java/log4j-12-api:2
	dev-java/mchange-commons:0
"

DEPEND="
	>=virtual/jdk-1.8:*
	${CP_DEPEND}
"

RDEPEND="
	>=virtual/jre-1.8:*
	${CP_DEPEND}
"

PATCHES=( "${FILESDIR}/c3p0-0.9.5.5-source-target.patch" )

src_prepare() {
	java-pkg_clean
	default #780585
	java-pkg-2_src_prepare
	java-pkg_jar-from --into lib/ log4j-12-api-2
	java-pkg_jar-from --into lib/ mchange-commons

	# Test sources interfere with Javadoc generation on JDK 11
	# Remove since the tests will never be run
	rm -r src/java/com/mchange/v2/c3p0/test ||
		die "Failed to remove unused test sources"
}

src_compile() {
	eant jar $(usev doc javadoc) \
		-Dant.build.javac.source="$(java-pkg_get-source)" \
		-Dant.build.javac.target="$(java-pkg_get-target)"
}

src_install() {
	java-pkg_newjar "build/${P}.jar"
	einstalldocs

	use doc && java-pkg_dojavadoc build/apidocs
	use examples && java-pkg_doexamples src/java/com/mchange/v2/c3p0/example
	use source && java-pkg_dosrc src/java/com/mchange/v2
}