org.springframework.data.repository.init.ResourceReaderRepositoryPopulator.java Source code

Introduction

Here is the source code for org.springframework.data.repository.init.ResourceReaderRepositoryPopulator.java

Source

/*
 * Copyright 2012 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 org.springframework.data.repository.init;

import java.io.IOException;
import java.io.Serializable;
import java.util.Arrays;
import java.util.Collection;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.context.ApplicationEventPublisher;
import org.springframework.context.ApplicationEventPublisherAware;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternResolver;
import org.springframework.data.repository.CrudRepository;
import org.springframework.data.repository.support.Repositories;
import org.springframework.util.Assert;

/**
 * A {@link RepositoryPopulator} using a {@link ResourceReader} to read objects from the configured {@link Resource}s.
 * 
 * @author Oliver Gierke
 * @since 1.4
 */
public class ResourceReaderRepositoryPopulator implements RepositoryPopulator, ApplicationEventPublisherAware {

    private static final Log LOG = LogFactory.getLog(ResourceReaderRepositoryPopulator.class);

    private final ResourcePatternResolver resolver;
    private final ResourceReader reader;
    private final ClassLoader classLoader;

    private ApplicationEventPublisher publisher;
    private Collection<Resource> resources;

    /**
     * Creates a new {@link ResourceReaderRepositoryPopulator} using the given {@link ResourceReader}.
     * 
     * @param reader must not be {@literal null}.
     */
    public ResourceReaderRepositoryPopulator(ResourceReader reader) {
        this(reader, null);
    }

    /**
     * Createsa a new {@link ResourceReaderRepositoryPopulator} using the given {@link ResourceReader} and
     * {@link ClassLoader}.
     * 
     * @param reader must not be {@literal null}.
     * @param classLoader
     */
    public ResourceReaderRepositoryPopulator(ResourceReader resourceReader, ClassLoader classLoader) {

        Assert.notNull(resourceReader);

        this.reader = resourceReader;
        this.classLoader = classLoader;
        this.resolver = classLoader == null ? new PathMatchingResourcePatternResolver()
                : new PathMatchingResourcePatternResolver(classLoader);
    }

    /**
     * Configures the location of the {@link Resource}s to be used to initialize the repositories.
     * 
     * @param location must not be {@literal null} or empty.
     * @throws IOException
     */
    public void setResourceLocation(String location) throws IOException {
        Assert.hasText(location);
        setResources(resolver.getResources(location));
    }

    /**
     * Configures the {@link Resource}s to be used to initialize the repositories.
     * 
     * @param resources
     */
    public void setResources(Resource... resources) {
        this.resources = Arrays.asList(resources);
    }

    /* 
     * (non-Javadoc)
     * @see org.springframework.context.ApplicationEventPublisherAware#setApplicationEventPublisher(org.springframework.context.ApplicationEventPublisher)
     */
    public void setApplicationEventPublisher(ApplicationEventPublisher publisher) {
        this.publisher = publisher;
    }

    /* 
     * (non-Javadoc)
     * @see org.springframework.data.repository.init.RepositoryPopulator#initialize()
     */
    public void populate(Repositories repositories) {

        for (Resource resource : resources) {

            LOG.info(String.format("Reading resource: %s", resource));

            Object result = readObjectFrom(resource);

            if (result instanceof Collection) {
                for (Object element : (Collection<?>) result) {
                    if (element != null) {
                        persist(element, repositories);
                    } else {
                        LOG.info("Skipping null element found in unmarshal result!");
                    }
                }
            } else {
                persist(result, repositories);
            }
        }

        if (publisher != null) {
            publisher.publishEvent(new RepositoriesPopulatedEvent(this, repositories));
        }
    }

    /**
     * Reads the given resource into an {@link Object} using the configured {@link ResourceReader}.
     * 
     * @param resource must not be {@literal null}.
     * @return
     */
    private Object readObjectFrom(Resource resource) {
        try {
            return reader.readFrom(resource, classLoader);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    /**
     * Persists the given {@link Object} using a suitable repository.
     * 
     * @param object must not be {@literal null}.
     * @param repositories must not be {@literal null}.
     */
    private void persist(Object object, Repositories repositories) {

        CrudRepository<Object, Serializable> repository = repositories.getRepositoryFor(object.getClass());
        LOG.debug(String.format("Persisting %s using repository %s", object, repository));
        repository.save(object);
    }
}