com.github.springtestdbunit.dataset.AbstractDataSetLoader.java Source code

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Here is the source code for com.github.springtestdbunit.dataset.AbstractDataSetLoader.java

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/*
 * Copyright 2010 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;
}