Improved the newInstance method in ClasspathUtils, and used this method from

the places where newInstances are made and Throwable is caught.


git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@278346 13f79535-47bb-0310-9956-ffa450edef68

src/main/org/apache/tools/ant/Main.java

@@ -29,6 +29,7 @@ import java.util.Vector;
 import org.apache.tools.ant.input.DefaultInputHandler;
 import org.apache.tools.ant.input.InputHandler;
 import org.apache.tools.ant.launch.AntMain;
+import org.apache.tools.ant.util.ClasspathUtils;
 import org.apache.tools.ant.util.FileUtils;
 
 
@@ -698,17 +699,13 @@ public class Main implements AntMain {
 
         for (int i = 0; i < listeners.size(); i++) {
             String className = (String) listeners.elementAt(i);
-            try {
-                BuildListener listener =
-                    (BuildListener) Class.forName(className).newInstance();
-                if (project != null) {
-                    project.setProjectReference(listener);
-                }
-                project.addBuildListener(listener);
-            } catch (Throwable exc) {
-                throw new BuildException("Unable to instantiate listener "
-                    + className, exc);
+            BuildListener listener =
+                    (BuildListener) ClasspathUtils.newInstance(className,
+                            Main.class.getClassLoader(), BuildListener.class);
+            if (project != null) {
+                project.setProjectReference(listener);
             }
+            project.addBuildListener(listener);
         }
     }
 
@@ -725,22 +722,11 @@ public class Main implements AntMain {
         if (inputHandlerClassname == null) {
             handler = new DefaultInputHandler();
         } else {
-            try {
-                handler = (InputHandler)
-                    (Class.forName(inputHandlerClassname).newInstance());
-                if (project != null) {
-                    project.setProjectReference(handler);
-                }
-            } catch (ClassCastException e) {
-                String msg = "The specified input handler class "
-                    + inputHandlerClassname
-                    + " does not implement the InputHandler interface";
-                throw new BuildException(msg);
-            } catch (Exception e) {
-                String msg = "Unable to instantiate specified input handler "
-                    + "class " + inputHandlerClassname + " : "
-                    + e.getClass().getName();
-                throw new BuildException(msg);
+            handler = (InputHandler) ClasspathUtils.newInstance(
+                    inputHandlerClassname, Main.class.getClassLoader(),
+                    InputHandler.class);
+            if (project != null) {
+                project.setProjectReference(handler);
             }
         }
         project.setInputHandler(handler);
@@ -760,17 +746,13 @@ public class Main implements AntMain {
         BuildLogger logger = null;
         if (loggerClassname != null) {
             try {
-                Class loggerClass = Class.forName(loggerClassname);
-                logger = (BuildLogger) (loggerClass.newInstance());
-            } catch (ClassCastException e) {
+                logger = (BuildLogger) ClasspathUtils.newInstance(
+                        loggerClassname, Main.class.getClassLoader(),
+                        BuildLogger.class);
+            } catch (BuildException e) {
                 System.err.println("The specified logger class "
                     + loggerClassname
-                    + " does not implement the BuildLogger interface");
-                throw new RuntimeException();
-            } catch (Exception e) {
-                System.err.println("Unable to instantiate specified logger "
-                    + "class " + loggerClassname + " : "
-                    + e.getClass().getName());
+                    + " could not be used because " + e.getMessage());
                 throw new RuntimeException();
             }
         } else {

src/main/org/apache/tools/ant/listener/MailLogger.java

@@ -27,11 +27,13 @@ import java.util.Enumeration;
 import java.util.StringTokenizer;
 
 import org.apache.tools.ant.BuildEvent;
+import org.apache.tools.ant.BuildException;
 import org.apache.tools.ant.DefaultLogger;
 import org.apache.tools.ant.Project;
 import org.apache.tools.ant.taskdefs.email.EmailAddress;
 import org.apache.tools.ant.taskdefs.email.Message;
 import org.apache.tools.ant.taskdefs.email.Mailer;
+import org.apache.tools.ant.util.ClasspathUtils;
 import org.apache.tools.ant.util.DateUtils;
 import org.apache.tools.ant.util.StringUtils;
 import org.apache.tools.mail.MailMessage;
@@ -239,14 +241,15 @@ public class MailLogger extends DefaultLogger {
                               String message)  {
         // convert the replyTo string into a vector of emailaddresses
         Mailer mailer = null;
-            try {
-                mailer =
-                    (Mailer) Class.forName("org.apache.tools.ant.taskdefs.email.MimeMailer")
-                    .newInstance();
-            } catch (Throwable e) {
-                log("Failed to initialise MIME mail: " + e.getMessage());
-                return;
-            }
+        try {
+            mailer = (Mailer) ClasspathUtils.newInstance(
+                    "org.apache.tools.ant.taskdefs.email.MimeMailer",
+                    MailLogger.class.getClassLoader(), Mailer.class);
+        } catch (BuildException e) {
+            Throwable t = e.getCause() == null ? e : e.getCause();
+            log("Failed to initialise MIME mail: " + t.getMessage());
+            return;
+        }
         Vector replyToList = vectorizeEmailAddresses(replyToString);
         mailer.setHost(host);
         mailer.setPort(port);

src/main/org/apache/tools/ant/taskdefs/compilers/CompilerAdapterFactory.java

@@ -20,6 +20,7 @@ package org.apache.tools.ant.taskdefs.compilers;
 import org.apache.tools.ant.BuildException;
 import org.apache.tools.ant.Project;
 import org.apache.tools.ant.Task;
+import org.apache.tools.ant.util.ClasspathUtils;
 import org.apache.tools.ant.util.JavaEnvUtils;
 
 /**
@@ -162,21 +163,9 @@ public final class CompilerAdapterFactory {
      */
     private static CompilerAdapter resolveClassName(String className)
         throws BuildException {
-        try {
-            Class c = Class.forName(className);
-            Object o = c.newInstance();
-            return (CompilerAdapter) o;
-        } catch (ClassNotFoundException cnfe) {
-            throw new BuildException("Compiler Adapter '" + className
-                    + "' can\'t be found.", cnfe);
-        } catch (ClassCastException cce) {
-            throw new BuildException(className + " isn\'t the classname of "
-                    + "a compiler adapter.", cce);
-        } catch (Throwable t) {
-            // for all other possibilities
-            throw new BuildException("Compiler Adapter " + className
-                    + " caused an interesting exception.", t);
-        }
+        return (CompilerAdapter) ClasspathUtils.newInstance(className,
+                CompilerAdapterFactory.class.getClassLoader(),
+                CompilerAdapter.class);
     }
 
 }

src/main/org/apache/tools/ant/taskdefs/email/EmailTask.java

@@ -25,8 +25,10 @@ import org.apache.tools.ant.BuildException;
 import org.apache.tools.ant.DirectoryScanner;
 import org.apache.tools.ant.Project;
 import org.apache.tools.ant.Task;
+import org.apache.tools.ant.listener.MailLogger;
 import org.apache.tools.ant.types.EnumeratedAttribute;
 import org.apache.tools.ant.types.FileSet;
+import org.apache.tools.ant.util.ClasspathUtils;
 
 /**
  * A task to send SMTP email. This is a refactoring of the SendMail and
@@ -399,14 +401,16 @@ public class EmailTask extends Task {
             if (encoding.equals(MIME)
                  || (encoding.equals(AUTO) && !autoFound)) {
                 try {
-                    mailer = (Mailer) Class.forName(
-                        "org.apache.tools.ant.taskdefs.email.MimeMailer")
-                        .newInstance();
+                    mailer = (Mailer) ClasspathUtils.newInstance(
+                            "org.apache.tools.ant.taskdefs.email.MimeMailer",
+                            EmailTask.class.getClassLoader(), Mailer.class);
                     autoFound = true;
                     log("Using MIME mail", Project.MSG_VERBOSE);
-                } catch (Throwable e) {
-                    log("Failed to initialise MIME mail: "
-                        + e.getMessage(), Project.MSG_WARN);
+                } catch (BuildException e) {
+                    Throwable t = e.getCause() == null ? e : e.getCause();
+                    log("Failed to initialise MIME mail: " + t.getMessage(),
+                            Project.MSG_WARN);
+                    return;
                 }
             }
             // SMTP auth only allowed with MIME mail
@@ -423,13 +427,16 @@ public class EmailTask extends Task {
             if (encoding.equals(UU)
                  || (encoding.equals(AUTO) && !autoFound)) {
                 try {
-                    mailer =
-                        (Mailer) Class.forName("org.apache.tools.ant.taskdefs.email.UUMailer")
-                        .newInstance();
+                    mailer = (Mailer) ClasspathUtils.newInstance(
+                            "org.apache.tools.ant.taskdefs.email.UUMailer",
+                            EmailTask.class.getClassLoader(), Mailer.class);
                     autoFound = true;
                     log("Using UU mail", Project.MSG_VERBOSE);
-                } catch (Throwable e) {
-                    log("Failed to initialise UU mail", Project.MSG_WARN);
+                } catch (BuildException e) {
+                    Throwable t = e.getCause() == null ? e : e.getCause();
+                    log("Failed to initialise UU mail: " + t.getMessage(),
+                            Project.MSG_WARN);
+                    return;
                 }
             }
             // try plain format

src/main/org/apache/tools/ant/taskdefs/optional/javah/JavahAdapterFactory.java

@@ -18,6 +18,7 @@ package org.apache.tools.ant.taskdefs.optional.javah;
 
 import org.apache.tools.ant.BuildException;
 import org.apache.tools.ant.ProjectComponent;
+import org.apache.tools.ant.util.ClasspathUtils;
 import org.apache.tools.ant.util.JavaEnvUtils;
 
 /**
@@ -77,20 +78,8 @@ public class JavahAdapterFactory {
      * isn't an instance of JavahAdapter.
      */
     private static JavahAdapter resolveClassName(String className)
-        throws BuildException {
-        try {
-            Class c = Class.forName(className);
-            Object o = c.newInstance();
-            return (JavahAdapter) o;
-        } catch (ClassNotFoundException cnfe) {
-            throw new BuildException("Can't load " + className, cnfe);
-        } catch (ClassCastException cce) {
-            throw new BuildException(className 
-                                     + " is not a Javah adapter", cce);
-        } catch (Throwable t) {
-            // for all other possibilities
-            throw new BuildException(className + " caused an interesting "
-                                     + "exception.", t);
-        }
+            throws BuildException {
+        return (JavahAdapter) ClasspathUtils.newInstance(className,
+                JavahAdapterFactory.class.getClassLoader(), JavahAdapter.class);
     }
 }

src/main/org/apache/tools/ant/taskdefs/optional/native2ascii/Native2AsciiAdapterFactory.java

@@ -18,6 +18,7 @@ package org.apache.tools.ant.taskdefs.optional.native2ascii;
 
 import org.apache.tools.ant.BuildException;
 import org.apache.tools.ant.ProjectComponent;
+import org.apache.tools.ant.util.ClasspathUtils;
 import org.apache.tools.ant.util.JavaEnvUtils;
 
 /**
@@ -77,20 +78,10 @@ public class Native2AsciiAdapterFactory {
      * isn't an instance of Native2AsciiAdapter.
      */
     private static Native2AsciiAdapter resolveClassName(String className)
-        throws BuildException {
-        try {
-            Class c = Class.forName(className);
-            Object o = c.newInstance();
-            return (Native2AsciiAdapter) o;
-        } catch (ClassNotFoundException cnfe) {
-            throw new BuildException("Can't load " + className, cnfe);
-        } catch (ClassCastException cce) {
-            throw new BuildException(className 
-                                     + " is not a Native2Ascii adapter", cce);
-        } catch (Throwable t) {
-            // for all other possibilities
-            throw new BuildException(className + " caused an interesting "
-                                     + "exception.", t);
-        }
+        throws BuildException 
+    {
+        return (Native2AsciiAdapter) ClasspathUtils.newInstance(className,
+            Native2AsciiAdapterFactory.class.getClassLoader(), 
+            Native2AsciiAdapter.class);
     }
 }

src/main/org/apache/tools/ant/taskdefs/optional/script/ScriptDef.java

@@ -34,6 +34,7 @@ import java.util.Set;
 import java.util.HashSet;
 import java.io.File;
 
+import org.apache.tools.ant.util.ClasspathUtils;
 import org.apache.tools.ant.util.ScriptRunner;
 
 /**
@@ -272,27 +273,13 @@ public class ScriptDef extends DefBase {
             */
             ClassLoader loader = createLoader();
 
-            Class instanceClass = null;
-            try {
-                instanceClass = Class.forName(classname, true, loader);
-            } catch (Throwable e) {
-                // try normal method
-                try {
-                    instanceClass = Class.forName(classname);
-                } catch (Throwable e2) {
-                    throw new BuildException("scriptdef: Unable to load "
-                        + "class " + classname + " for nested element <"
-                        + elementName + ">", e2);
-                }
+            try
+            {
+                instance = ClasspathUtils.newInstance(classname, loader);
+            } catch (BuildException e) {
+                instance = ClasspathUtils.newInstance(classname, ScriptDef.class.getClassLoader());
             }
 
-            try {
-                instance = instanceClass.newInstance();
-            } catch (Throwable e) {
-                throw new BuildException("scriptdef: Unable to create "
-                    + "element of class " + classname + " for nested "
-                    + "element <" + elementName + ">", e);
-            }
             getProject().setProjectReference(instance);
         }
 

src/main/org/apache/tools/ant/taskdefs/rmic/RmicAdapterFactory.java

@@ -19,6 +19,7 @@ package org.apache.tools.ant.taskdefs.rmic;
 
 import org.apache.tools.ant.BuildException;
 import org.apache.tools.ant.Task;
+import org.apache.tools.ant.util.ClasspathUtils;
 
 
 /**
@@ -28,10 +29,10 @@ import org.apache.tools.ant.Task;
  */
 public final class RmicAdapterFactory {
     /** The error message to be used when the compiler cannot be found. */
-    public static final String ERROR_UNKNOWN_COMPILER = "Cannot find the compiler or class: ";
+    public static final String ERROR_UNKNOWN_COMPILER = "Class not found: ";
 
     /** The error message to be used when the class is not an rmic adapter. */
-    public static final String ERROR_NOT_RMIC_ADAPTER = "Not an rmic adapter: ";
+    public static final String ERROR_NOT_RMIC_ADAPTER = "Class of unexpected Type: ";
 
     /** If the compiler has this name use a default compiler. */
     public static final String DEFAULT_COMPILER = "default";
@@ -93,20 +94,7 @@ public final class RmicAdapterFactory {
      */
     private static RmicAdapter resolveClassName(String className)
         throws BuildException {
-        try {
-            Class c = Class.forName(className);
-            Object o = c.newInstance();
-            return (RmicAdapter) o;
-        } catch (ClassNotFoundException cnfe) {
-            throw new BuildException(ERROR_UNKNOWN_COMPILER + className,
-                    cnfe);
-        } catch (ClassCastException cce) {
-            throw new BuildException(ERROR_NOT_RMIC_ADAPTER + className,
-                    cce);
-        } catch (Throwable t) {
-            // for all other possibilities
-            throw new BuildException(className + " caused an interesting "
-                                     + "exception.", t);
-        }
+    return (RmicAdapter) ClasspathUtils.newInstance(className,
+            RmicAdapterFactory.class.getClassLoader(), RmicAdapter.class);
     }
 }

src/main/org/apache/tools/ant/util/ClasspathUtils.java

@@ -235,18 +235,50 @@ public class ClasspathUtils {
      * @return The fresh object instance
      * @throws BuildException when loading or instantiation failed.
      */
+    public static Object newInstance(
+            String className,
+            ClassLoader userDefinedLoader) {
+        return newInstance(className, userDefinedLoader, Object.class);
+    }
+
+        
+        
+    /**
+     * Creates a fresh object instance of the specified classname.
+     *
+     * <p> This uses the userDefinedLoader to load the specified class,
+     * and then makes an instance using the default no-argument constructor.
+     * </p>
+     *
+     * @param className the full qualified class name to load.
+     * @param userDefinedLoader the classloader to use.
+     * @param expectedType the Class that the result should be assignment
+     * compatible with. (No ClassCastException will be thrown in case
+     * the result of this method is casted to the expectedType) 
+     * @return The fresh object instance
+     * @throws BuildException when loading or instantiation failed.
+     * @since Ant 1.7
+     */
     public static Object newInstance(
         String className,
-        ClassLoader userDefinedLoader) {
+        ClassLoader userDefinedLoader,
+        Class expectedType) {
         try {
-            Class clazz = userDefinedLoader.loadClass(className);
+            Class clazz = Class.forName(className, true, userDefinedLoader); 
             Object o = clazz.newInstance();
+            if (!expectedType.isInstance(o))
+            {
+                throw new BuildException(
+                    "Class of unexpected Type: " 
+                        + className
+                        + " expected :" 
+                        + expectedType);
+            }
             return o;
         } catch (ClassNotFoundException e) {
             throw new BuildException(
-                "Class "
-                    + className
-                    + " not found by the specific classLoader.",
+                "Class not found: "
+                    + className,
                 e);
         } catch (InstantiationException e) {
             throw new BuildException(
@@ -262,9 +294,32 @@ public class ClasspathUtils {
                     + ". Specified class should have a "
                     + "public constructor.",
                 e);
+        } catch (LinkageError e) {
+            throw new BuildException(
+                "Class "
+                    + className
+                    + " could not be loaded because of an invalid dependency.", 
+                e);
         }
     }
 
+    /**
+     * Creates a fresh object instance of the specified classname.
+     *
+     * <p> This uses the userDefinedLoader to load the specified class,
+     * and then makes an instance using the default no-argument constructor.
+     * </p>
+     *
+     * @param className the full qualified class name to load.
+     * @param userDefinedLoader the classloader to use.
+     * @param expectedType the Class that the result should be assignment
+     * compatible with. (No ClassCastException will be thrown in case
+     * the result of this method is casted to the expectedType) 
+     * @return The fresh object instance
+     * @throws BuildException when loading or instantiation failed.
+     */
+
+    
     /**
      * Obtains a delegate that helps out with classic classpath configuration.
      *

src/main/org/apache/tools/ant/util/regexp/RegexpMatcherFactory.java

@@ -19,6 +19,7 @@ package org.apache.tools.ant.util.regexp;
 
 import org.apache.tools.ant.BuildException;
 import org.apache.tools.ant.Project;
+import org.apache.tools.ant.util.ClasspathUtils;
 
 /**
  * Simple Factory Class that produces an implementation of
@@ -99,13 +100,10 @@ public class RegexpMatcherFactory {
      * @exception BuildException if an error occurs
      */
     protected RegexpMatcher createInstance(String className)
-        throws BuildException {
-        try {
-            Class implClass = Class.forName(className);
-            return (RegexpMatcher) implClass.newInstance();
-        } catch (Throwable t) {
-            throw new BuildException(t);
-        }
+        throws BuildException 
+    {
+        return (RegexpMatcher) ClasspathUtils.newInstance(className,
+                RegexpMatcherFactory.class.getClassLoader(), RegexpMatcher .class);
     }
 
     /**