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/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2002-2004, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
** $Id$
\* */
package scala.mobile;
import java.net._;
import scala.collection.mutable._;
/** The class <code>Location</code> provides a <code>create</code>
* method to instantiate objects from a network location by
* specifying the URL address of the jar/class file.<p/>
*
* An update of the jar/class file should not break your code as far
* as the used class names and method signatures are the same.<p/>
*
* Example:<pre>
* <b>val</b> url = <b>new</b> URL("http://scala.epfl.ch/classes/examples.jar");
* <b>val</b> obj = <b>new</b> Location(url) create "examples.sort";</pre>
*
* @see <a href="Code-class.html">Code</a>
*
* @author Stephane Micheloud
* @version 1.0, 04/05/2004
*/
class Location(url: URL) {
/** A cache containing all class loaders of this location.
*/
private var lcache: Map[URL, ClassLoader] = new HashMap;
/** The class loader associated with this location.
*/
private val loader = if (url == null)
ClassLoader.getSystemClassLoader()
else
lcache.get(url) match {
case Some(cl) =>
cl
case _ =>
val cl = new URLClassLoader(Predef.Array(url));
lcache(url) = cl;
cl
};
/** A cache containing all classes of this location.
*/
private var ccache: Map[String, java.lang.Class] = new HashMap;
/** Return the code description for the string <code>className</code>
* at this location.
*
* @param the name of the class
* @return the code description corresponding to <code>className</code>
*/
def create(className: String) = new Code(
ccache.get(className) match {
case Some(clazz) =>
clazz
case _ =>
val clazz = if (loader.loadClass(className).isInterface()) {
// Scala source: class A { ... };
// Java bytecode: interface A.class + class A$class.class
loader.loadClass(className + "$class");
}
else {
// Scala source: object A { ... };
// Java bytecode: interface A.class + class A$.class
loader.loadClass(className + "$");
}
ccache(className) = clazz;
clazz
}
);
}
/** The object <code>Location</code> can be used to instantiate
* objects on the same Java VM. It is just provided to illustrate
* the special case where resources are available locally.<p/>
*
* Example:<pre>
* <b>val</b> obj = Location.create("xcode.Math");
* <b>val</b> x = obj[Int, Int]("square")(5);</pre>
*
* @author Stephane Micheloud
* @version 1.0, 04/05/2004
*/
object Location extends Location(null);
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