Add the <classloader> task.

It'll create a new loader or add paths to an existing loader.

The main use is for the core loader - used to load ant regular
and optional tasks.

This is similar with embed, but 90% of the code is not needed for
ant1.6 ( due to the delayed task creation ).

For both import and classloader I changed the name of the class
so embed can still compile.


git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@273688 13f79535-47bb-0310-9956-ffa450edef68

src/main/org/apache/tools/ant/taskdefs/Classloader.java

@@ -0,0 +1,234 @@
+/*
+ * 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.taskdefs;
+
+import org.apache.tools.ant.*;
+import org.apache.tools.ant.types.*;
+
+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;
+
+/**
+ * EXPERIMENTAL
+ * Create or modifies ClassLoader. The required pathRef parameter
+ * will be used to add classpath elements.
+ *
+ * The classpath is a regular path. Currently only file components are
+ * supported ( future extensions may allow URLs ).
+ *
+ * You can modify the core loader by not specifying any name or using
+ * "ant.coreLoader". ( the core loader is used to load system ant
+ * tasks and for taskdefs that don't specify an explicit path ).
+ *
+ * Taskdef and typedef can use the loader you create if the name follows
+ * the "ant.loader.NAME" pattern. NAME will be used as a pathref when
+ * calling taskdef.
+ *
+ * This tasks will not modify the core loader if "build.sysclasspath=only"
+ *
+ * The typical use is:
+ * <pre>
+ *  &lt;path id="ant.deps" &gt;
+ *     &lt;fileset dir="myDir" &gt;
+ *        &lt;include name="junit.jar, bsf.jar, js.jar, etc"/&gt;
+ *     &lt;/fileset&gt;
+ *  &lt;/path&gt;
+ *
+ *  &lt;classloader pathRef="ant.deps" /&gt;
+ *
+ * </pre>
+ *
+ * @author Costin Manolache
+ */
+public class Classloader extends Task {
+    public static final String SYSTEM_LOADER_REF="ant.coreLoader";
+
+    private String name=null;
+    private Path path;
+    private boolean reset=false;
+    private boolean reverse=false;
+    private String parentName=null;
+
+    public Classloader() {
+    }
+
+    /** Name of the loader. If none, the default loader will be modified
+     *
+     * @param name
+     */
+    public void setName(String name) {
+        this.name=name;
+    }
+
+    /** Reset the classloader, if it already exists. A new loader will
+     * be created and all the references to the old one will be removed.
+     * ( it is not possible to remove paths from a loader ). The new
+     * path will be used.
+     *
+     * @param b
+     */
+    public void setReset(boolean b) {
+        this.reset=b;
+    }
+
+    // TODO
+    public void setReverse(boolean b ) {
+        this.reverse=b;
+    }
+
+    // TODO: add exceptions for delegation or reverse
+
+    // TODO
+    public void setParentName( String name ) {
+        this.parentName=name;
+    }
+
+
+    /** Specify which path will be used. If the loader already exists
+     *  and is an AntClassLoader ( or any other loader we can extend ),
+     *  the path will be added to the loader.
+     */
+    public void setPathRef( Reference pathRef ) throws BuildException {
+        path=(Path)pathRef.getReferencedObject(project);
+    }
+
+
+    public void execute() {
+        try {
+            // Gump friendly - don't mess with the core loader if only classpath
+            if( "only".equals( project.getProperty("build.sysclasspath")) &&
+                    (name==null || SYSTEM_LOADER_REF.equals( name ))) {
+                log( "Changing the system loader is disabled " +
+                        "by build.sysclasspath=only",
+                        Project.MSG_WARN);
+                return;
+            }
+
+            String loaderName=(name==null) ? SYSTEM_LOADER_REF : name;
+
+            Object obj=project.getReference(loaderName);
+            if( reset ) {
+                // Are any other references held ? Can we 'close' the loader
+                // so it removes the locks on jars ?
+                obj=null; // a new one will be created.
+            }
+
+            // XXX maybe use reflection to addPathElement ( other patterns ?)
+            if( obj!=null && !(obj instanceof AntClassLoader )) {
+                log( "Referenced object is not an AntClassLoader",
+                        Project.MSG_ERR);
+                return;
+            }
+
+            AntClassLoader acl=(AntClassLoader)obj;
+
+            if( acl==null ) {
+                // Construct a class loader
+                Object parent=null;
+                if( parentName != null ) {
+                    parent=project.getReference(parentName);
+                    if( !(parent instanceof ClassLoader) ) {
+                        parent=null;
+                    }
+                }
+                if( parent==null ) {
+                    parent=this.getClass().getClassLoader();
+                }
+
+                acl=new AntClassLoader( (ClassLoader)parent,
+                        project, path, reverse );
+                project.addReference( loaderName, acl );
+                if( name==null ) {
+                    // This allows the core loader to load optional tasks
+                    // without delegating
+                    acl.addLoaderPackageRoot( "org.apache.tools.ant.taskdefs.optional");
+                    project.setCoreLoader(acl);
+                }
+            }
+            if( path != null ) {
+                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());
+                        log("Adding to class loader " +  acl + " " + f.getAbsolutePath(),
+                                Project.MSG_DEBUG);
+                    }
+                }
+            }
+
+            // XXX add exceptions
+
+        } catch( Exception ex ) {
+            ex.printStackTrace();
+        }
+    }
+}