org.springframework.batch.item.data.RepositoryItemWriter.java Source code

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Here is the source code for org.springframework.batch.item.data.RepositoryItemWriter.java

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/*
 * Copyright 2012-2019 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
 *
 *      https://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.batch.item.data;

import java.lang.reflect.InvocationTargetException;
import java.util.List;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.batch.item.ItemWriter;
import org.springframework.batch.item.adapter.AbstractMethodInvokingDelegator.InvocationTargetThrowableWrapper;
import org.springframework.batch.item.adapter.DynamicMethodInvocationException;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.data.repository.CrudRepository;
import org.springframework.util.Assert;
import org.springframework.util.CollectionUtils;
import org.springframework.util.MethodInvoker;

/**
 * <p>
 * A {@link org.springframework.batch.item.ItemWriter} wrapper for a
 * {@link org.springframework.data.repository.CrudRepository} from Spring Data.
 * </p>
 *
 * <p>
 * It depends on {@link org.springframework.data.repository.CrudRepository#saveAll(Iterable)}
 * method to store the items for the chunk.  Performance will be determined by that
 * implementation more than this writer.
 * </p>
 *
 * <p>
 * As long as the repository provided is thread-safe, this writer is also thread-safe once
 * properties are set (normal singleton behavior), so it can be used in multiple concurrent
 * transactions.
 * </p>
 *
 * <p>
 * NOTE: The {@code RepositoryItemWriter} only stores Java Objects i.e. non primitives.
 * </p>
 *
 * @author Michael Minella
 * @author Mahmoud Ben Hassine
 * @since 2.2
 */
public class RepositoryItemWriter<T> implements ItemWriter<T>, InitializingBean {

    protected static final Log logger = LogFactory.getLog(RepositoryItemWriter.class);

    private CrudRepository<T, ?> repository;

    private String methodName;

    /**
     * Specifies what method on the repository to call.  This method must have the type of
     * object passed to this writer as the <em>sole</em> argument.
     *
     * @param methodName {@link String} containing the method name.
     */
    public void setMethodName(String methodName) {
        this.methodName = methodName;
    }

    /**
     * Set the {@link org.springframework.data.repository.CrudRepository} implementation
     * for persistence
     *
     * @param repository the Spring Data repository to be set
     */
    public void setRepository(CrudRepository<T, ?> repository) {
        this.repository = repository;
    }

    /**
     * Write all items to the data store via a Spring Data repository.
     *
     * @see org.springframework.batch.item.ItemWriter#write(java.util.List)
     */
    @Override
    public void write(List<? extends T> items) throws Exception {
        if (!CollectionUtils.isEmpty(items)) {
            doWrite(items);
        }
    }

    /**
     * Performs the actual write to the repository.  This can be overridden by
     * a subclass if necessary.
     *
     * @param items the list of items to be persisted.
     *
     * @throws Exception thrown if error occurs during writing.
     */
    protected void doWrite(List<? extends T> items) throws Exception {
        if (logger.isDebugEnabled()) {
            logger.debug("Writing to the repository with " + items.size() + " items.");
        }

        MethodInvoker invoker = createMethodInvoker(repository, methodName);

        for (T object : items) {
            invoker.setArguments(new Object[] { object });
            doInvoke(invoker);
        }
    }

    /**
     * Check mandatory properties - there must be a repository.
     */
    @Override
    public void afterPropertiesSet() throws Exception {
        Assert.state(repository != null, "A CrudRepository implementation is required");
    }

    private Object doInvoke(MethodInvoker invoker) throws Exception {
        try {
            invoker.prepare();
        } catch (ClassNotFoundException e) {
            throw new DynamicMethodInvocationException(e);
        } catch (NoSuchMethodException e) {
            throw new DynamicMethodInvocationException(e);
        }

        try {
            return invoker.invoke();
        } catch (InvocationTargetException e) {
            if (e.getCause() instanceof Exception) {
                throw (Exception) e.getCause();
            } else {
                throw new InvocationTargetThrowableWrapper(e.getCause());
            }
        } catch (IllegalAccessException e) {
            throw new DynamicMethodInvocationException(e);
        }
    }

    private MethodInvoker createMethodInvoker(Object targetObject, String targetMethod) {
        MethodInvoker invoker = new MethodInvoker();
        invoker.setTargetObject(targetObject);
        invoker.setTargetMethod(targetMethod);
        return invoker;
    }
}