Initial attempt to fix the optional.jar ( for 1.5+ ). The ProjectHelper

will replace all optional tasks, using an AntClassLoader to load
( delegation disabled for the optional package ).

Next step is to add a task that adds jars to the loader for optional.
( like junit.jar, etc ).


git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@273106 13f79535-47bb-0310-9956-ffa450edef68

proposal/sandbox/embed/ProjectHelperImpl2.java

@@ -97,6 +97,39 @@ public class ProjectHelperImpl2 extends ProjectHelper {
      */
     private static SAXParserFactory parserFactory = null;
 
+    /** Will prepare the class loader to allow dynamic modifications
+        of the classpath. Optional tasks are loaded in a different loader.
+    */
+    public void initClassLoader(Project project) {
+        try {
+            // reverse loader
+            AntClassLoader acl=new AntClassLoader( this.getClass().getClassLoader(), true );
+            acl.addLoaderPackageRoot( "org.apache.tools.ant.taskdefs.optional");
+
+            // XXX find the classpath
+            String antHome=project.getProperty( "ant.home" );
+            File optionalJar=new File( antHome + "/lib/optional.jar" );
+            System.out.println("Optional.jar = " +optionalJar.getAbsolutePath());
+            acl.addPathElement(optionalJar.getAbsolutePath() );
+            
+            // reload all optional tasks in this loader.
+            Hashtable tasks=project.getTaskDefinitions();
+            Enumeration keys=tasks.keys();
+            while( keys.hasMoreElements() ) {
+                String n=(String)keys.nextElement();
+                Class c=(Class)tasks.get(n);
+                if( ! c.getName().startsWith( "org.apache.tools.ant.taskdefs.optional" ))
+                    continue;
+                // System.out.println("Reloading " + n + " " + c + " " + c.getClassLoader() );
+                c=acl.loadClass( c.getName() );
+                tasks.put( n, c );
+                // System.out.println("Loaded " + n + " " + c.getClassLoader() );
+            }
+        } catch( Exception ex ) {
+            ex.printStackTrace();
+        }
+    }
+    
     /**
      * Parses the project file, configuring the project as it goes.
      * 
@@ -104,6 +137,9 @@ public class ProjectHelperImpl2 extends ProjectHelper {
      *                           be read
      */
     public void parse(Project project, Object source) throws BuildException {
+        // re-init class loader for optional.jar
+        initClassLoader( project );
+
         AntXmlContext context=new AntXmlContext();
         if(source instanceof File) {
             context.buildFile=(File)source;

proposal/sandbox/embed/build.xml

@@ -2,13 +2,15 @@
   <property name="ant.src" location="../../.." />
   <property name="ant.build" location="${ant.src}/build" />
   <property name="debug" value="true"/>
-
+    
   <target name="main">
-    <copy file="ProjectHelperImpl2.java"  
+    <copy id="test" file="ProjectHelperImpl2.java"  
           todir="${ant.src}/src/main/org/apache/tools/ant/helper" />
     <copy file="RuntimeConfigurable2.java"  
           todir="${ant.src}/src/main/org/apache/tools/ant" />
 
+    <echo message="${toString:test}" />
+
     <javac srcdir="${ant.src}/src"  
            debug="${debug}"
            destdir="${ant.build}/classes" >
@@ -27,6 +29,8 @@
       <include name="org/apache/tools/ant/helper/ProjectHelperImpl2*" />
       <include name="org/apache/tools/ant/RuntimeConfigurable2*" />
     </jar>
+
+    <copy file="ant-sax2.jar" todir="${ant.home}/lib" />
   </target>
 
   <target name="clean">