org.springframework.batch.item.database.JdbcBatchItemWriter.java Source code

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/*
 * Copyright 2006-2013 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.batch.item.database;

import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import javax.sql.DataSource;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.batch.item.ItemWriter;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.dao.DataAccessException;
import org.springframework.dao.EmptyResultDataAccessException;
import org.springframework.dao.InvalidDataAccessApiUsageException;
import org.springframework.jdbc.core.PreparedStatementCallback;
import org.springframework.jdbc.core.namedparam.NamedParameterJdbcOperations;
import org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate;
import org.springframework.jdbc.core.namedparam.SqlParameterSource;
import org.springframework.util.Assert;

/**
 * <p>{@link ItemWriter} that uses the batching features from
 * {@link NamedParameterJdbcTemplate} to execute a batch of statements for all items
 * provided.</p>
 *
 * The user must provide an SQL query and a special callback in the for of either
 * {@link ItemPreparedStatementSetter} or {@link ItemSqlParameterSourceProvider}.
 * You can use either named parameters or the traditional '?' placeholders. If you use the
 * named parameter support then you should provide a {@link ItemSqlParameterSourceProvider},
 * otherwise you should provide a  {@link ItemPreparedStatementSetter}.
 * This callback would be responsible for mapping the item to the parameters needed to
 * execute the SQL statement.<br>
 *
 * It is expected that {@link #write(List)} is called inside a transaction.<br>
 *
 * The writer is thread-safe after its properties are set (normal singleton
 * behavior), so it can be used to write in multiple concurrent transactions.
 *
 * @author Dave Syer
 * @author Thomas Risberg
 * @author Michael Minella
 * @since 2.0
 */
public class JdbcBatchItemWriter<T> implements ItemWriter<T>, InitializingBean {

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

    private NamedParameterJdbcOperations namedParameterJdbcTemplate;

    private ItemPreparedStatementSetter<T> itemPreparedStatementSetter;

    private ItemSqlParameterSourceProvider<T> itemSqlParameterSourceProvider;

    private String sql;

    private boolean assertUpdates = true;

    private int parameterCount;

    private boolean usingNamedParameters;

    /**
     * Public setter for the flag that determines whether an assertion is made
     * that all items cause at least one row to be updated.
     * @param assertUpdates the flag to set. Defaults to true;
     */
    public void setAssertUpdates(boolean assertUpdates) {
        this.assertUpdates = assertUpdates;
    }

    /**
     * Public setter for the query string to execute on write. The parameters
     * should correspond to those known to the
     * {@link ItemPreparedStatementSetter}.
     * @param sql the query to set
     */
    public void setSql(String sql) {
        this.sql = sql;
    }

    /**
     * Public setter for the {@link ItemPreparedStatementSetter}.
     * @param preparedStatementSetter the {@link ItemPreparedStatementSetter} to
     * set. This is required when using traditional '?' placeholders for the SQL statement.
     */
    public void setItemPreparedStatementSetter(ItemPreparedStatementSetter<T> preparedStatementSetter) {
        this.itemPreparedStatementSetter = preparedStatementSetter;
    }

    /**
     * Public setter for the {@link ItemSqlParameterSourceProvider}.
     * @param itemSqlParameterSourceProvider the {@link ItemSqlParameterSourceProvider} to
     * set. This is required when using named parameters for the SQL statement and the type
     * to be written does not implement {@link Map}.
     */
    public void setItemSqlParameterSourceProvider(
            ItemSqlParameterSourceProvider<T> itemSqlParameterSourceProvider) {
        this.itemSqlParameterSourceProvider = itemSqlParameterSourceProvider;
    }

    /**
     * Public setter for the data source for injection purposes.
     *
     * @param dataSource {@link javax.sql.DataSource} to use for querying against
     */
    public void setDataSource(DataSource dataSource) {
        if (namedParameterJdbcTemplate == null) {
            this.namedParameterJdbcTemplate = new NamedParameterJdbcTemplate(dataSource);
        }
    }

    /**
     * Public setter for the {@link NamedParameterJdbcOperations}.
     * @param namedParameterJdbcTemplate the {@link NamedParameterJdbcOperations} to set
     */
    public void setJdbcTemplate(NamedParameterJdbcOperations namedParameterJdbcTemplate) {
        this.namedParameterJdbcTemplate = namedParameterJdbcTemplate;
    }

    /**
     * Check mandatory properties - there must be a SimpleJdbcTemplate and an SQL statement plus a
     * parameter source.
     */
    @Override
    public void afterPropertiesSet() {
        Assert.notNull(namedParameterJdbcTemplate, "A DataSource or a NamedParameterJdbcTemplate is required.");
        Assert.notNull(sql, "An SQL statement is required.");
        List<String> namedParameters = new ArrayList<String>();
        parameterCount = JdbcParameterUtils.countParameterPlaceholders(sql, namedParameters);
        if (namedParameters.size() > 0) {
            if (parameterCount != namedParameters.size()) {
                throw new InvalidDataAccessApiUsageException(
                        "You can't use both named parameters and classic \"?\" placeholders: " + sql);
            }
            usingNamedParameters = true;
        }
        if (!usingNamedParameters) {
            Assert.notNull(itemPreparedStatementSetter,
                    "Using SQL statement with '?' placeholders requires an ItemPreparedStatementSetter");
        }
    }

    /* (non-Javadoc)
     * @see org.springframework.batch.item.ItemWriter#write(java.util.List)
     */
    @SuppressWarnings("unchecked")
    @Override
    public void write(final List<? extends T> items) throws Exception {

        if (!items.isEmpty()) {

            if (logger.isDebugEnabled()) {
                logger.debug("Executing batch with " + items.size() + " items.");
            }

            int[] updateCounts;

            if (usingNamedParameters) {
                if (items.get(0) instanceof Map && this.itemSqlParameterSourceProvider == null) {
                    updateCounts = namedParameterJdbcTemplate.batchUpdate(sql,
                            items.toArray(new Map[items.size()]));
                } else {
                    SqlParameterSource[] batchArgs = new SqlParameterSource[items.size()];
                    int i = 0;
                    for (T item : items) {
                        batchArgs[i++] = itemSqlParameterSourceProvider.createSqlParameterSource(item);
                    }
                    updateCounts = namedParameterJdbcTemplate.batchUpdate(sql, batchArgs);
                }
            } else {
                updateCounts = namedParameterJdbcTemplate.getJdbcOperations().execute(sql,
                        new PreparedStatementCallback<int[]>() {
                            @Override
                            public int[] doInPreparedStatement(PreparedStatement ps)
                                    throws SQLException, DataAccessException {
                                for (T item : items) {
                                    itemPreparedStatementSetter.setValues(item, ps);
                                    ps.addBatch();
                                }
                                return ps.executeBatch();
                            }
                        });
            }

            if (assertUpdates) {
                for (int i = 0; i < updateCounts.length; i++) {
                    int value = updateCounts[i];
                    if (value == 0) {
                        throw new EmptyResultDataAccessException("Item " + i + " of " + updateCounts.length
                                + " did not update any rows: [" + items.get(i) + "]", 1);
                    }
                }
            }
        }
    }
}