package org.liquibase.maven.plugins;

 import java.io.IOException;

 import java.io.InputStream;

 import java.net.URL;

 import java.net.URLClassLoader;

 import java.util.ArrayList;

 import java.util.Enumeration;

 import java.util.List;

 import liquibase.resource.ResourceAccessor;

 import liquibase.util.StringUtils;

 /**

  * Implementation of liquibase.FileOpener for Maven which will use a default or user specified {@link ClassLoader} to

  * load files/resources.

  * 

  * @see liquibase.resource.ResourceAccessor

  */

 public class MavenResourceAccessor implements ResourceAccessor {

     /**

      * The class loader to use to load files/resources from.

      */

     private ClassLoader _loader;

     /**

      * Creates a {@link liquibase.resource.ResourceAccessor} that uses the classloader for the class.

      */

     public MavenResourceAccessor() {

         this(MavenResourceAccessor.class.getClassLoader());

     }

     /**

      * Creates a {@link liquibase.resource.ResourceAccessor} that will use the specified {@link ClassLoader} to load

      * files.

      * 

      * @param cl

      *            The {@link ClassLoader} to use to load files/resources.

      */

     public MavenResourceAccessor(ClassLoader cl) {

         _loader = cl;

     }

     public InputStream getResourceAsStream(String file) throws IOException {

         return _loader.getResourceAsStream(file);

     }

     public Enumeration<URL> getResources(String packageName) throws IOException {

         return _loader.getResources(packageName);

     }

     public ClassLoader toClassLoader() {

         return _loader;

     }

     @Override

     public String toString() {

         String description;

         if (_loader instanceof URLClassLoader) {

             List<String> urls = new ArrayList<String>();

             for (URL url : ((URLClassLoader) _loader).getURLs()) {

                 urls.add(url.toExternalForm());

             }

             description = StringUtils.join(urls, ",");

         } else {

             description = _loader.getClass().getName();

         }

         return getClass().getName() + "(" + description + ")";

     }

 }