Added (back) TaskAdapter2. It'll allow more flexibility on how 'normal'

beans are turned into tasks - it allows to specify the method name.

It'll also be extended to support mbeans or other types of tasks.


git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@273177 13f79535-47bb-0310-9956-ffa450edef68

proposal/embed/src/java/org/apache/tools/ant/helper/TaskAdapter2.java

@@ -0,0 +1,229 @@
+/*
+ * 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.helper;
+
+import java.lang.reflect.Method;
+import org.apache.tools.ant.*;
+
+/**
+ * Uses introspection to "adapt" an arbitrary Bean which doesn't
+ * itself extend Task, but still contains an execute method and optionally 
+ * a setProject method.
+ *
+ *  The adapter can also be used to wrap tasks that are loaded in a different class loader
+ *  by ant, when used in programatic mode.
+ *
+ * @author Costin Manolache
+ */
+public class TaskAdapter2 extends Task {
+
+    /** Object to act as a proxy for. */
+    private Object proxy;
+    private String methodName="execute";
+    
+    /**
+     * Checks whether or not a class is suitable to be adapted by TaskAdapter.
+     *
+     * This only checks conditions which are additionally required for 
+     * tasks adapted by TaskAdapter. Thus, this method should be called by
+     * Project.checkTaskClass.
+     *
+     * Throws a BuildException and logs as Project.MSG_ERR for
+     * conditions that will cause the task execution to fail.
+     * Logs other suspicious conditions with Project.MSG_WARN.
+     * 
+     * @param taskClass Class to test for suitability. 
+     *                  Must not be <code>null</code>.
+     * @param project   Project to log warnings/errors to. 
+     *                  Must not be <code>null</code>.
+     * 
+     * @see Project#checkTaskClass(Class)
+     */
+    public static void checkTaskClass(final Class taskClass, final Project project) {
+        // Any task can be used via adapter. If it doesn't have any execute()
+        // method, no problem - it will do nothing, but still get an 'id'
+        // and be registered in the project reference table and useable by other
+        // tasks.
+        
+        if( true )
+            return;
+
+        // don't have to check for interface, since then
+        // taskClass would be abstract too.
+        try {
+            final Method executeM = taskClass.getMethod( "execute", null );
+            // don't have to check for public, since
+            // getMethod finds public method only.
+            // don't have to check for abstract, since then
+            // taskClass would be abstract too.
+            if(!Void.TYPE.equals(executeM.getReturnType())) {
+                final String message =
+                    "return type of execute() should be void but was \""+
+                    executeM.getReturnType()+"\" in " + taskClass;
+                project.log(message, Project.MSG_WARN);
+            }
+        } catch(NoSuchMethodException e) {
+            final String message = "No public execute() in " + taskClass;
+            project.log(message, Project.MSG_ERR);
+            throw new BuildException(message);
+        }
+    }
+
+    private IntrospectionHelper ih;
+
+    void setIntrospectionHelper( IntrospectionHelper ih ) {
+        this.ih=ih;
+    }
+
+    IntrospectionHelper getIntrospectionHelper() {
+        if( ih==null ) {
+            ih = IntrospectionHelper.getHelper(target.getClass());
+        }
+        return ih;
+    }
+    
+    /** Experimental, non-public method for better 'adaptation'
+     *
+     */
+    void setAttribute( String name, String value )
+        throws BuildException
+    {
+        try {
+            ih.setAttribute( project, proxy, name, value );
+        } catch( BuildException ex ) {
+            if( "do".equals( name ) ) {
+                setDo( value );
+            } else {
+                throw ex;
+            }
+        }
+    }
+        
+    /** Set the 'action' method. This allow beans implementing multiple
+     * actions or using methods other than 'execute()' to be used in ant
+     * without any modification.
+     * 
+     *  @ant:experimental 
+     */
+    public void setDo(String methodName ) {
+        this.methodName=methodName;
+    }
+    
+    /**
+     * Executes the proxied task.
+     */
+    public void execute() throws BuildException {
+        Method setProjectM = null;
+        try {
+            Class c = proxy.getClass();
+            setProjectM = 
+                c.getMethod( "setProject", new Class[] {Project.class});
+            if(setProjectM != null) {
+                setProjectM.invoke(proxy, new Object[] {project});
+            }
+        } catch (NoSuchMethodException e) {
+            // ignore this if the class being used as a task does not have
+            // a set project method.
+        } catch( Exception ex ) {
+            log("Error setting project in " + proxy.getClass(), 
+                Project.MSG_ERR);
+            throw new BuildException( ex );
+        }
+
+
+        Method executeM=null;
+        try {
+            Class c=proxy.getClass();
+            executeM=c.getMethod( methodName, new Class[0] );
+            if( executeM == null ) {
+                log("No public " + methodName + "() in " + proxy.getClass(), Project.MSG_ERR);
+                throw new BuildException("No public " + methodName +"() in " + proxy.getClass());
+            }
+            executeM.invoke(proxy, null);
+            return; 
+        } catch (java.lang.reflect.InvocationTargetException ie) {
+            log("Error in " + proxy.getClass(), Project.MSG_ERR);
+            Throwable t = ie.getTargetException();
+            if (t instanceof BuildException) {
+                throw ((BuildException) t);
+            } else {
+                throw new BuildException(t);
+            }
+        } catch( Exception ex ) {
+            log("Error in " + proxy.getClass(), Project.MSG_ERR);
+            throw new BuildException( ex );
+        }
+
+    }
+    
+    /**
+     * Sets the target object to proxy for.
+     * 
+     * @param o The target object. Must not be <code>null</code>.
+     */
+    public void setProxy(Object o) {
+        this.proxy = o;
+    }
+
+    /**
+     * Returns the target object being proxied.
+     * 
+     * @return the target proxy object
+     */
+    public Object getProxy() {
+        return this.proxy ;
+    }
+
+}