mirror of https://github.com/sbt/sbt.git
78 lines
2.6 KiB
ReStructuredText
78 lines
2.6 KiB
ReStructuredText
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============
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Java Sources
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============
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sbt has support for compiling Java sources with the limitation that
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dependency tracking is limited to the dependencies present in compiled
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class files.
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Usage
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=====
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- ``compile`` will compile the sources under ``src/main/java`` by
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default.
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- ``test-compile`` will compile the sources under ``src/test/java`` by
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default.
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Pass options to the Java compiler by setting ``javac-options``:
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::
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javacOptions += "-g:none"
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As with options for the Scala compiler, the arguments are not parsed by
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sbt. Multi-element options, such as ``-source 1.5``, are specified like:
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::
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javacOptions ++= Seq("-source", "1.5")
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You can specify the order in which Scala and Java sources are built with
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the ``compile-order`` setting. Possible values are from the
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``CompileOrder`` enumeration: ``Mixed``, ``JavaThenScala``, and
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``ScalaThenJava``. If you have circular dependencies between Scala and
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Java sources, you need the default, ``Mixed``, which passes both Java
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and Scala sources to ``scalac`` and then compiles the Java sources with
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``javac``. If you do not have circular dependencies, you can use one of
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the other two options to speed up your build by not passing the Java
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sources to ``scalac``. For example, if your Scala sources depend on your
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Java sources, but your Java sources do not depend on your Scala sources,
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you can do:
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::
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compileOrder := CompileOrder.JavaThenScala
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To specify different orders for main and test sources, scope the setting
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by configuration:
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::
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// Java then Scala for main sources
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compileOrder in Compile := CompileOrder.JavaThenScala
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// allow circular dependencies for test sources
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compileOrder in Test := CompileOrder.Mixed
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Note that in an incremental compilation setting, it is not practical to
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ensure complete isolation between Java sources and Scala sources because
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they share the same output directory. So, previously compiled classes
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not involved in the current recompilation may be picked up. A clean
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compile will always provide full checking, however.
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By default, sbt includes ``src/main/scala`` and ``src/main/java`` in its
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list of unmanaged source directories. For Java-only projects, the
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unnecessary Scala directories can be ignored by modifying
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``unmanagedSourceDirectories``:
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::
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// Include only src/main/java in the compile configuration
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unmanagedSourceDirectories in Compile <<= Seq(javaSource in Compile).join
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// Include only src/test/java in the test configuration
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unmanagedSourceDirectories in Test <<= Seq(javaSource in Test).join
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However, there should not be any harm in leaving the Scala directories
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if they are empty.
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