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Scala example source code file (ScalaTool.scala)
This example Scala source code file (ScalaTool.scala) is included in the DevDaily.com
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The Scala ScalaTool.scala source code
/* __ *\
** ________ ___ / / ___ Scala Ant Tasks **
** / __/ __// _ | / / / _ | (c) 2005-2011, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
package scala.tools.ant
import java.io.{File, InputStream, FileWriter}
import org.apache.tools.ant.BuildException
import org.apache.tools.ant.types.{Path, Reference}
/** <p>
* An Ant task that generates a shell or batch script to execute a
* Scala program.
* This task can take the following parameters as attributes:
* </p>
* <li>file (mandatory),
* <li>class (mandatory),
* <li>platforms,
* <li>classpath,
* <li>properties,
* <li>javaflags,
* <li>toolflags.
*
* @author Gilles Dubochet
* @version 1.1
*/
class ScalaTool extends ScalaMatchingTask {
private def emptyPath = new Path(getProject)
/*============================================================================*\
** Ant user-properties **
\*============================================================================*/
abstract class PermissibleValue {
val values: List[String]
def isPermissible(value: String): Boolean =
(value == "") || values.exists(_.startsWith(value))
}
/** Defines valid values for the platforms property. */
object Platforms extends PermissibleValue {
val values = List("unix", "windows")
}
/** The path to the exec script file. ".bat" will be appended for the
* Windows BAT file, if generated. */
private var file: Option[File] = None
/** The main class to run. */
private var mainClass: Option[String] = None
/** Supported platforms for the script. Either "unix" or "windows".
* Defaults to both. */
private var platforms: List[String] = List("unix", "windows")
/** An (optional) path to all JARs that this script depend on. Paths must be
* relative to the scala home directory. If not set, all JAR archives and
* folders in "lib/" are automatically added. */
private var classpath: List[String] = Nil
/** An (optional) path to JARs that this script depends on relative to the
* ant project's basedir. */
private var classpathPath: Path = emptyPath
/** Comma-separated Java system properties to pass to the JRE. Properties
* are formatted as name=value. Properties scala.home, scala.tool.name and
* scala.tool.version are always set. */
private var properties: List[(String, String)] = Nil
/** Additional flags passed to the JRE ("java [javaFlags] class"). */
private var javaFlags: String = ""
/** Additional flags passed to the tool ("java class [toolFlags]"). Can only
* be set when a main class is defined. */
private var toolFlags: String = ""
/*============================================================================*\
** Properties setters **
\*============================================================================*/
/** Sets the file attribute. */
def setFile(input: File) =
file = Some(input)
/** Sets the main class attribute. */
def setClass(input: String) =
mainClass = Some(input)
/** Sets the platforms attribute. */
def setPlatforms(input: String) = {
platforms = input.split(",").toList.flatMap { s: String =>
val st = s.trim
if (Platforms.isPermissible(st))
(if (input != "") List(st) else Nil)
else {
buildError("Platform " + st + " does not exist.")
}
}
}
/**
* Sets the classpath with which to run the tool.
* Note that this mechanism of setting the classpath is generally preferred
* for general purpose scripts, as this does not assume all elements are
* relative to the ant basedir. Additionally, the platform specific demarcation
* of any script variables (e.g. ${SCALA_HOME} or %SCALA_HOME%) can be specified
* in a platform independant way (e.g. @SCALA_HOME@) and automatically translated
* for you.
*/
def setClassPath(input: String): Unit = {
classpath = classpath ::: input.split(",").toList
}
/**
* A special method that allows ant classpath path definitions to be nested
* within this ant task.
*/
def createClassPath: Path = classpathPath.createPath()
/**
* Adds an Ant Path reference to the tool's classpath.
* Note that all entries in the path must exist either relative to the project
* basedir or with an absolute path to a file in the filesystem. As a result,
* this is not a mechanism for setting the classpath for more general use scripts,
* such as those distributed within sbaz distribution packages.
*/
def setClassPathRef(input: Reference): Unit = {
val tmpPath = emptyPath
tmpPath.setRefid(input)
classpath = classpath ::: tmpPath.list.toList
}
/** Sets JVM properties that will be set whilst running the tool. */
def setProperties(input: String) = {
properties = input.split(",").toList.flatMap { s: String =>
val st = s.trim
val stArray = st.split("=", 2)
if (stArray.length == 2) {
if (input != "") List(Pair(stArray(0), stArray(1))) else Nil
}
else
buildError("Property " + st + " is not formatted properly.")
}
}
/** Sets flags to be passed to the Java interpreter. */
def setJavaflags(input: String) =
javaFlags = input.trim
/** Sets flags to be passed to the tool. */
def setToolflags(input: String) =
toolFlags = input.trim
/*============================================================================*\
** Properties getters **
\*============================================================================*/
/** Gets the value of the classpath attribute in a Scala-friendly form.
* @return The class path as a list of files. */
private def getUnixclasspath: String =
transposeVariableMarkup(classpath.mkString("", ":", "").replace('\\', '/'), "${", "}")
/** Gets the value of the classpath attribute in a Scala-friendly form.
* @return The class path as a list of files. */
private def getWinclasspath: String =
transposeVariableMarkup(classpath.mkString("", ";", "").replace('/', '\\'), "%", "%")
private def getProperties: String =
properties.map({
case Pair(name,value) => "-D" + name + "=\"" + value + "\""
}).mkString("", " ", "")
/*============================================================================*\
** Compilation and support methods **
\*============================================================================*/
// XXX encoding and generalize
private def getResourceAsCharStream(clazz: Class[_], resource: String): Stream[Char] = {
val stream = clazz.getClassLoader() getResourceAsStream resource
if (stream == null) Stream.empty
else Stream continually stream.read() takeWhile (_ != -1) map (_.asInstanceOf[Char])
}
// Converts a variable like @SCALA_HOME@ to ${SCALA_HOME} when pre = "${" and post = "}"
private def transposeVariableMarkup(text: String, pre: String, post: String) : String = {
val chars = scala.io.Source.fromString(text)
val builder = new StringBuilder()
while (chars.hasNext) {
val char = chars.next
if (char == '@') {
var char = chars.next
val token = new StringBuilder()
while (chars.hasNext && char != '@') {
token.append(char)
char = chars.next
}
if (token.toString == "")
builder.append('@')
else
builder.append(pre + token.toString + post)
} else builder.append(char)
}
builder.toString
}
private def readAndPatchResource(resource: String, tokens: Map[String, String]): String = {
val chars = getResourceAsCharStream(this.getClass, resource).iterator
val builder = new StringBuilder()
while (chars.hasNext) {
val char = chars.next
if (char == '@') {
var char = chars.next
val token = new StringBuilder()
while (chars.hasNext && char != '@') {
token.append(char)
char = chars.next
}
if (tokens.contains(token.toString))
builder.append(tokens(token.toString))
else if (token.toString == "")
builder.append('@')
else
builder.append("@" + token.toString + "@")
} else builder.append(char)
}
builder.toString
}
private def writeFile(file: File, content: String) =
if (file.exists() && !file.canWrite())
buildError("File " + file + " is not writable")
else {
val writer = new FileWriter(file, false)
writer.write(content)
writer.close()
}
/*============================================================================*\
** The big execute method **
\*============================================================================*/
/** Performs the tool creation. */
override def execute() = {
// Tests if all mandatory attributes are set and valid.
if (file.isEmpty) buildError("Attribute 'file' is not set.")
if (mainClass.isEmpty) buildError("Main class must be set.")
val resourceRoot = "scala/tools/ant/templates/"
val patches = Map (
("class", mainClass.get),
("properties", getProperties),
("javaflags", javaFlags),
("toolflags", toolFlags)
)
// Consolidate Paths into classpath
classpath = classpath ::: classpathPath.list.toList
// Generate the scripts
if (platforms.contains("unix")) {
val unixPatches = patches + (("classpath", getUnixclasspath))
val unixTemplateResource = resourceRoot + "tool-unix.tmpl"
val unixTemplate = readAndPatchResource(unixTemplateResource, unixPatches)
writeFile(file.get, unixTemplate)
}
if (platforms.contains("windows")) {
val winPatches = patches + (("classpath", getWinclasspath))
val winTemplateResource = resourceRoot + "tool-windows.tmpl"
val winTemplate = readAndPatchResource(winTemplateResource, winPatches)
writeFile(new File(file.get.getAbsolutePath() + ".bat"), winTemplate)
}
}
}
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