/*

  * Copyright 2002-2016 the original author or authors

  *

  * Licensed under the Apache License, Version 2.0 (the "License");

  * you may not use this file except in compliance with the License.

  * You may obtain a copy of the License at

  *

  *   http://www.apache.org/licenses/LICENSE-2.0

  *

  * Unless required by applicable law or agreed to in writing, software

  * distributed under the License is distributed on an "AS IS" BASIS,

  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

  * See the License for the specific language governing permissions and

  * limitations under the License.

  */

 package com.github.springtestdbunit.dataset;

 import org.dbunit.dataset.IDataSet;

 import org.springframework.core.io.ClassRelativeResourceLoader;

 import org.springframework.core.io.Resource;

 import org.springframework.core.io.ResourceLoader;

 /**

  * Abstract data set loader, which provides a basis for concrete implementations of the {@link DataSetLoader} strategy.

  * Provides a <em>Template Method</em> based approach for {@link #loadDataSet(Class, String) loading} data using a

  * Spring {@link #getResourceLoader resource loader}.

  *

  * @author Phillip Webb

  *

  * @see #getResourceLoader

  * @see #getResourceLocations

  * @see #createDataSet(Resource)

  */

 public abstract class AbstractDataSetLoader implements DataSetLoader {

         /**

          * Loads a {@link IDataSet dataset} from {@link Resource}s obtained from the specified <tt>location</tt>. Each

          * <tt>location</tt> can be mapped to a number of potential {@link #getResourceLocations resources}, the first

          * resource that {@link Resource#exists() exists} will be used. {@link Resource}s are loaded using the

          * {@link ResourceLoader} returned from {@link #getResourceLoader}.

          * <p>

          * If no resource can be found then <tt>null</tt> will be returned.

          *

          * @see #createDataSet(Resource)

          * @see com.github.springtestdbunit.dataset.DataSetLoader#loadDataSet(Class, String) java.lang.String)

          */

         public IDataSet loadDataSet(Class<?> testClass, String location) throws Exception {

                 ResourceLoader resourceLoader = getResourceLoader(testClass);

                 String[] resourceLocations = getResourceLocations(testClass, location);

                 for (String resourceLocation : resourceLocations) {

                         Resource resource = resourceLoader.getResource(resourceLocation);

                         if (resource.exists()) {

                                 return createDataSet(resource);

                         }

                 }

                 return null;

         }

         /**

          * Gets the {@link ResourceLoader} that will be used to load the dataset {@link Resource}s.

          * @param testClass The class under test

          * @return a resource loader

          */

         protected ResourceLoader getResourceLoader(Class<?> testClass) {

                 return new ClassRelativeResourceLoader(testClass);

         }

         /**

          * Get the resource locations that should be considered when attempting to load a dataset from the specified

          * location.

          * @param testClass The class under test

          * @param location The source location

          * @return an array of potential resource locations

          */

         protected String[] getResourceLocations(Class<?> testClass, String location) {

                 return new String[] { location };

         }

         /**

          * Factory method used to create the {@link IDataSet dataset}

          * @param resource an existing resource that contains the dataset data

          * @return a dataset

          * @throws Exception if the dataset could not be loaded

          */

         protected abstract IDataSet createDataSet(Resource resource) throws Exception;

 }