////////////////////////////////////////////////////////////////////////////////

 // checkstyle: Checks Java source code for adherence to a set of rules.

 // Copyright (C) 2001-2014  Oliver Burn

 //

 // This library is free software; you can redistribute it and/or

 // modify it under the terms of the GNU Lesser General Public

 // License as published by the Free Software Foundation; either

 // version 2.1 of the License, or (at your option) any later version.

 //

 // This library is distributed in the hope that it will be useful,

 // but WITHOUT ANY WARRANTY; without even the implied warranty of

 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 // Lesser General Public License for more details.

 //

 // You should have received a copy of the GNU Lesser General Public

 // License along with this library; if not, write to the Free Software

 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 ////////////////////////////////////////////////////////////////////////////////

 package com.puppycrawl.tools.checkstyle;

 import com.google.common.collect.Sets;

 import com.puppycrawl.tools.checkstyle.api.CheckstyleException;

 import java.util.Set;

 /**

  * A factory for creating objects from package names and names.

  * @author Rick Giles

  * @author lkuehne

  */

 class PackageObjectFactory implements ModuleFactory

 {

     /** a list of package names to prepend to class names */

     private final Set<String> mPackages;

     /** the class loader used to load Checkstyle core and custom modules. */

     private final ClassLoader mModuleClassLoader;

     /**

      * Creates a new <code>PackageObjectFactory</code> instance.

      * @param aPackageNames the list of package names to use

      * @param aModuleClassLoader class loader used to load Checkstyle

      *          core and custom modules

      */

     public PackageObjectFactory(Set<String> aPackageNames,

             ClassLoader aModuleClassLoader)

     {

         if (aModuleClassLoader == null) {

             throw new IllegalArgumentException(

                     "aModuleClassLoader must not be null");

         }

         //create a copy of the given set, but retain ordering

         mPackages = Sets.newLinkedHashSet(aPackageNames);

         mModuleClassLoader = aModuleClassLoader;

     }

     /**

      * Registers a package name to use for shortName resolution.

      * @param aPackageName the package name

      */

     void addPackage(String aPackageName)

     {

         mPackages.add(aPackageName);

     }

     /**

      * Creates a new instance of a class from a given name. If the name is

      * a classname, creates an instance of the named class. Otherwise, creates

      * an instance of a classname obtained by concatenating the given

      * to a package name from a given list of package names.

      * @param aName the name of a class.

      * @return the <code>Object</code>

      * @throws CheckstyleException if an error occurs.

      */

     private Object doMakeObject(String aName)

         throws CheckstyleException

     {

         //try aName first

         try {

             return createObject(aName);

         }

         catch (final CheckstyleException ex) {

             ; // keep looking

         }

         //now try packages

         for (String packageName : mPackages) {

             final String className = packageName + aName;

             try {

                 return createObject(className);

             }

             catch (final CheckstyleException ex) {

                 ; // keep looking

             }

         }

         throw new CheckstyleException("Unable to instantiate " + aName);

     }

     /**

      * Creates a new instance of a named class.

      * @param aClassName the name of the class to instantiate.

      * @return the <code>Object</code> created by mLoader.

      * @throws CheckstyleException if an error occurs.

      */

     private Object createObject(String aClassName)

         throws CheckstyleException

     {

         try {

             final Class<?> clazz = Class.forName(aClassName, true,

                     mModuleClassLoader);

             return clazz.newInstance();

         }

         catch (final ClassNotFoundException e) {

             throw new CheckstyleException(

                 "Unable to find class for " + aClassName, e);

         }

         catch (final InstantiationException e) {

             ///CLOVER:OFF

             throw new CheckstyleException(

                 "Unable to instantiate " + aClassName, e);

             ///CLOVER:ON

         }

         catch (final IllegalAccessException e) {

             ///CLOVER:OFF

             throw new CheckstyleException(

                 "Unable to instantiate " + aClassName, e);

             ///CLOVER:ON

         }

     }

     /**

      * Creates a new instance of a class from a given name, or that name

      * concatenated with "Check". If the name is

      * a classname, creates an instance of the named class. Otherwise, creates

      * an instance of a classname obtained by concatenating the given name

      * to a package name from a given list of package names.

      * @param aName the name of a class.

      * @return the <code>Object</code> created by aLoader.

      * @throws CheckstyleException if an error occurs.

      */

     public Object createModule(String aName)

         throws CheckstyleException

     {

         try {

             return doMakeObject(aName);

         }

         catch (final CheckstyleException ex) {

             //try again with suffix "Check"

             try {

                 return doMakeObject(aName + "Check");

             }

             catch (final CheckstyleException ex2) {

                 throw new CheckstyleException(

                     "Unable to instantiate " + aName, ex2);

             }

         }

     }

 }