First version of the <systemPath>.

You need to include ant-sax2.jar in ant/lib, define a <path id='foo'> that includes
all the jars that you need ( junit.jar, etc ) and then use
 <systemPath pathRef='foo' /> to create the loader and reload all optional tasks.

After this step all optional tasks will work in the same way as if you have
included the jars from the <path> definition in ant/lib.

I did some basic tests and seems to work fine - note that <taskdef> will
work as before, i.e. if you explicitely define tasks that need optional
jars ( or redefine optional task ), you'll have the old behavior ( i.e.
require things in CLASSPATH ).

I'll try to find what changes are need for <import> and re-do the build
for ant-sax2, then do more testings.


git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@273118 13f79535-47bb-0310-9956-ffa450edef68

proposal/sandbox/embed/ProjectHelperImpl2.java

@@ -82,6 +82,7 @@ import javax.xml.parsers.SAXParserFactory;
 import javax.xml.parsers.SAXParser;
 import javax.xml.parsers.ParserConfigurationException;
 
+import org.apache.tools.ant.types.SystemPath;
 /**
  * Sax2 based project reader
  *
@@ -97,39 +98,6 @@ 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.
      * 
@@ -137,9 +105,9 @@ 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 );
-
+        // Hook our one tasks.
+        project.addDataTypeDefinition( "systemPath" , SystemPath.class );
+        
         AntXmlContext context=new AntXmlContext();
         if(source instanceof File) {
             context.buildFile=(File)source;

proposal/sandbox/embed/SystemPath.java

@@ -0,0 +1,191 @@
+/*
+ * The Apache Software License, Version 1.1
+ *
+ * Copyright (c) 2000-2002 The Apache Software Foundation.  All rights
+ * reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * 3. The end-user documentation included with the redistribution, if
+ *    any, must include the following acknowlegement:
+ *       "This product includes software developed by the
+ *        Apache Software Foundation (http://www.apache.org/)."
+ *    Alternately, this acknowlegement may appear in the software itself,
+ *    if and wherever such third-party acknowlegements normally appear.
+ *
+ * 4. The names "The Jakarta Project", "Ant", and "Apache Software
+ *    Foundation" must not be used to endorse or promote products derived
+ *    from this software without prior written permission. For written
+ *    permission, please contact apache@apache.org.
+ *
+ * 5. Products derived from this software may not be called "Apache"
+ *    nor may "Apache" appear in their names without prior written
+ *    permission of the Apache Group.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of the Apache Software Foundation.  For more
+ * information on the Apache Software Foundation, please see
+ * <http://www.apache.org/>.
+ */
+
+package org.apache.tools.ant.types;
+
+import org.apache.tools.ant.*;
+
+import java.io.*;
+import java.util.*;
+import org.xml.sax.Locator;
+import org.xml.sax.InputSource;
+//import org.xml.sax.HandlerBase;
+import org.xml.sax.SAXParseException;
+import org.xml.sax.XMLReader;
+import org.xml.sax.SAXException;
+import org.xml.sax.DocumentHandler;
+import org.xml.sax.Attributes;
+import org.xml.sax.AttributeList;
+import org.xml.sax.helpers.XMLReaderAdapter;
+import org.xml.sax.helpers.DefaultHandler;
+import org.xml.sax.helpers.AttributeListImpl;
+
+import javax.xml.parsers.SAXParserFactory;
+import javax.xml.parsers.SAXParser;
+import javax.xml.parsers.ParserConfigurationException;
+
+/**
+ * Specify a system path, to be used to load optional.jar and all
+ * related libraries.
+ *
+ * Using the specified path it'll try to load or reload all optional
+ * tasks. The typical use is:
+ * <pre>
+ *  &lt;path id="ant.deps" &gt;
+ *     &lt;fileset ... /&gt;
+ *  &lt;/path&gt;
+ *
+ *  &lt;systemPath pathRef="ant.deps" /&gt;
+ *
+ *  &lt;junit ... /&gt;
+ * </pre>
+ *
+ * This requires that ant-sax2.jar is included in ant/lib.
+ *
+ * It has a single property, a reference to a &lt;path&gt; containing all
+ * the jars that you need. It'll automatically reload optional.jar
+ * tasks in a different (non-delegating) loader.
+ *
+ * @author Costin Manolache
+ */
+public class SystemPath extends DataType {
+    public static final String SYSTEM_LOADER_REF="ant.system.loader";
+    
+    public SystemPath() {
+    }
+
+    /** Specify which path will be used.
+     */
+    public void setPathRef( Reference pathRef ) throws BuildException {
+        Path path=(Path)pathRef.getReferencedObject(project);
+
+        initSystemLoader(path);
+
+    }
+    
+    /** Will prepare the class loader to allow dynamic modifications
+     *   of the classpath. Optional tasks are loaded in a different loader.
+     */
+    private void initSystemLoader(Path path) {
+        try {
+            if( project.getReference( SYSTEM_LOADER_REF ) != null )
+                return; // already done that.
+            
+            // reverse loader
+            AntClassLoader acl=new AntClassLoader( this.getClass().getClassLoader(), true );
+            acl.addLoaderPackageRoot( "org.apache.tools.ant.taskdefs.optional");
+            project.addReference( SYSTEM_LOADER_REF, acl );
+            
+            
+            String list[]=path.list();
+            for( int i=0; i<list.length; i++ ) {
+                File f= new File( list[i] );
+                if( f.exists() ) {
+                    acl.addPathElement(f.getAbsolutePath());
+                }
+            }
+            
+            // XXX find the classpath
+            String antHome=project.getProperty( "ant.home" );
+            File optionalJar=new File( antHome + "/lib/optional.jar" );
+            if( optionalJar.exists() )
+                acl.addPathElement(optionalJar.getAbsolutePath() );
+
+            // reinit the loader for optional, if they were in /lib/
+            Hashtable tasks=project.getTaskDefinitions();
+
+            //System.out.println("Replacing jars" );
+            // reload all optional tasks in this loader.
+            // Some tasks weren't defined by the normal init(), since deps were missing.
+            String defs = "/org/apache/tools/ant/taskdefs/defaults.properties";
+
+            try {
+                Properties props = new Properties();
+                InputStream in = this.getClass().getResourceAsStream(defs);
+                if (in == null) {
+                    throw new BuildException("Can't load default task list");
+                }
+                props.load(in);
+                in.close();
+                
+                Enumeration enum = props.propertyNames();
+                while (enum.hasMoreElements()) {
+                    String key = (String) enum.nextElement();
+                    String value = props.getProperty(key);
+                    if( ! value.startsWith( "org.apache.tools.ant.taskdefs.optional" ))
+                        continue;
+                    // other classes that needs to be replaced ??
+                    try {
+                        Class taskClass = acl.loadClass(value);
+                        project.addTaskDefinition(key, taskClass);
+                        //System.out.println("Loaded " + key + " " + taskClass.getClassLoader() );
+                    } catch (NoClassDefFoundError ncdfe) {
+                        log("Could not load a dependent class ("
+                            + ncdfe.getMessage() + ") for task " + key, Project.MSG_DEBUG);
+                    } catch (ClassNotFoundException cnfe) {
+                        log("Could not load class (" + value
+                            + ") for task " + key, Project.MSG_DEBUG);
+                    } catch (Exception ex) {
+                        ex.printStackTrace();
+                    }
+                }
+            } catch (IOException ioe) {
+                throw new BuildException("Can't load default task list");
+            }
+            
+        } catch( Exception ex ) {
+            ex.printStackTrace();
+        }
+    }
+}

proposal/sandbox/embed/build.xml

@@ -4,13 +4,19 @@
   <property name="debug" value="true"/>
     
   <target name="main">
-    <copy id="test" file="ProjectHelperImpl2.java"  
+    <copy 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" />
+    <copy file="RuntimeConfigurable2.java"  
+          todir="${ant.src}/src/main/org/apache/tools/ant" />
+    <copy file="RuntimeConfigurable2.java"  
+          todir="${ant.src}/src/main/org/apache/tools/ant" />
     <copy file="PropertyInterceptor.java"  
           todir="${ant.src}/src/main/org/apache/tools/ant" />
-    <copy file="PropertyHelper.java"  
+    <copy file="SystemPath.java"  
+          todir="${ant.src}/src/main/org/apache/tools/ant/types" />
+    <copy id="test" file="PropertyHelper.java"  
           todir="${ant.src}/src/main/org/apache/tools/ant" />
 
     <echo message="${toString:test}" />
@@ -23,6 +29,7 @@
       <include name="**/PropertyHelper.java" />
       <include name="**/PropertyInterceptor.java" />
       <include name="**/RuntimeConfigurable2.java" />
+      <include name="**/SystemPath.java" />
     </javac>
 
     <mkdir dir="${ant.build}/classes/META-INF/services" />
@@ -36,6 +43,7 @@
       <include name="org/apache/tools/ant/RuntimeConfigurable2*" />
       <include name="org/apache/tools/ant/PropertyHelper*" />
       <include name="org/apache/tools/ant/PropertyInterceptor*" />
+      <include name="org/apache/tools/ant/types/SystemPath*" />
     </jar>
 
     <copy file="ant-sax2.jar" todir="${ant.home}/lib" />