Add in a TypeFactory that will reload a specified set of URLs everytime create() is called which allows statics to be used in tasks if they absolutely have to be

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@271201 13f79535-47bb-0310-9956-ffa450edef68

proposal/myrmidon/src/java/org/apache/myrmidon/interfaces/type/ReloadingTypeFactory.java

@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) The Apache Software Foundation. All rights reserved.
+ *
+ * This software is published under the terms of the Apache Software License
+ * version 1.1, a copy of which has been included with this distribution in
+ * the LICENSE.txt file.
+ */
+package org.apache.myrmidon.interfaces.type;
+
+import java.net.URL;
+import java.net.URLClassLoader;
+
+/**
+ * This is a TypeFactory that will recreate the ClassLoader each time the
+ * create() method is called. This is to provide support for types that
+ * use static variables to cache information. While this is a extremely bad
+ * practice, sometimes this is unavoidable - especially when using third party
+ * libraries.
+ *
+ * @author <a href="mailto:peter@apache.org">Peter Donald</a>
+ * @version CVS $Revision$ $Date$
+ */
+public class ReloadingTypeFactory
+    extends DefaultTypeFactory
+{
+    /**
+     * The URLs that are used to construct the ClassLoader.
+     */
+    private URL[] m_urls;
+
+    ///The parent classLoader (if any)
+    private ClassLoader m_parent;
+
+    /**
+     * Construct a factory that recreats a ClassLoader from specified
+     * URLs and with specified parent ClassLoader. The specified urls must
+     * not be null.
+     */
+    public ReloadingTypeFactory( final URL[] urls,
+                                 final ClassLoader parent )
+    {
+        if( null == urls )
+        {
+            throw new NullPointerException( "urls" );
+        }
+        m_urls = urls;
+        m_parent = parent;
+    }
+
+    protected ClassLoader getClassLoader()
+    {
+        System.out.println( "ReloadingTypeFactory.getClassLoader" );
+        return new URLClassLoader( m_urls, m_parent );
+    }
+}