| 1 | /* |
| 2 | * Copyright 2006-2007 the original author or authors. |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | package org.springframework.batch.item.database; |
| 17 | |
| 18 | import java.sql.PreparedStatement; |
| 19 | import java.sql.SQLException; |
| 20 | import java.util.Iterator; |
| 21 | import java.util.Set; |
| 22 | |
| 23 | import org.springframework.batch.item.ClearFailedException; |
| 24 | import org.springframework.batch.item.ItemWriter; |
| 25 | import org.springframework.batch.repeat.RepeatContext; |
| 26 | import org.springframework.beans.factory.InitializingBean; |
| 27 | import org.springframework.dao.DataAccessException; |
| 28 | import org.springframework.jdbc.core.JdbcOperations; |
| 29 | import org.springframework.jdbc.core.PreparedStatementCallback; |
| 30 | import org.springframework.util.Assert; |
| 31 | |
| 32 | /** |
| 33 | * {@link ItemWriter} that uses the batching features from |
| 34 | * {@link PreparedStatement} if available and can take some rudimentary steps to |
| 35 | * locate a failure during a flush, and identify the items that failed. When one |
| 36 | * of those items is encountered again the batch is flushed aggressively so that |
| 37 | * the bad item is eventually identified and can be dealt with in isolation.<br/> |
| 38 | * |
| 39 | * The user must provide an SQL query and a special callback |
| 40 | * {@link ItemPreparedStatementSetter}, which is responsible for mapping the |
| 41 | * item to a PreparedStatement.<br/> |
| 42 | * |
| 43 | * It is expected that {@link #write(Object)} is called inside a transaction, |
| 44 | * and that {@link #flush()} is then subsequently called before the transaction |
| 45 | * commits, or {@link #clear()} before it rolls back.<br/> |
| 46 | * |
| 47 | * The writer is thread safe after its properties are set (normal singleton |
| 48 | * behaviour), so it can be used to write in multiple concurrent transactions. |
| 49 | * Note, however, that the set of failed items is stored in a collection |
| 50 | * internally, and this collection is never cleared, so it is not a great idea |
| 51 | * to go on using the writer indefinitely. Normally it would be used for the |
| 52 | * duration of a batch job and then discarded. |
| 53 | * |
| 54 | * @author Dave Syer |
| 55 | * |
| 56 | */ |
| 57 | public class BatchSqlUpdateItemWriter extends AbstractTransactionalResourceItemWriter implements InitializingBean { |
| 58 | |
| 59 | /** |
| 60 | * Key for items processed in the current transaction {@link RepeatContext}. |
| 61 | */ |
| 62 | private static final String ITEMS_PROCESSED = BatchSqlUpdateItemWriter.class.getName() + ".ITEMS_PROCESSED"; |
| 63 | |
| 64 | private JdbcOperations jdbcTemplate; |
| 65 | |
| 66 | private ItemPreparedStatementSetter preparedStatementSetter; |
| 67 | |
| 68 | private String sql; |
| 69 | |
| 70 | /** |
| 71 | * Public setter for the query string to execute on write. The parameters |
| 72 | * should correspond to those known to the |
| 73 | * {@link ItemPreparedStatementSetter}. |
| 74 | * @param sql the query to set |
| 75 | */ |
| 76 | public void setSql(String sql) { |
| 77 | this.sql = sql; |
| 78 | } |
| 79 | |
| 80 | /** |
| 81 | * Public setter for the {@link ItemPreparedStatementSetter}. |
| 82 | * @param preparedStatementSetter the {@link ItemPreparedStatementSetter} to |
| 83 | * set |
| 84 | */ |
| 85 | public void setItemPreparedStatementSetter(ItemPreparedStatementSetter preparedStatementSetter) { |
| 86 | this.preparedStatementSetter = preparedStatementSetter; |
| 87 | } |
| 88 | |
| 89 | /** |
| 90 | * Public setter for the {@link JdbcOperations}. |
| 91 | * @param jdbcTemplate the {@link JdbcOperations} to set |
| 92 | */ |
| 93 | public void setJdbcTemplate(JdbcOperations jdbcTemplate) { |
| 94 | this.jdbcTemplate = jdbcTemplate; |
| 95 | } |
| 96 | |
| 97 | /** |
| 98 | * Check mandatory properties - there must be a delegate. |
| 99 | */ |
| 100 | public void afterPropertiesSet() throws Exception { |
| 101 | Assert.notNull(jdbcTemplate, "BatchSqlUpdateItemWriter requires an data source."); |
| 102 | Assert.notNull(preparedStatementSetter, "BatchSqlUpdateItemWriter requires a ItemPreparedStatementSetter"); |
| 103 | } |
| 104 | |
| 105 | /** |
| 106 | * Create and execute batch prepared statement. |
| 107 | */ |
| 108 | protected void doFlush() { |
| 109 | final Set processed = getProcessed(); |
| 110 | if (!processed.isEmpty()) { |
| 111 | jdbcTemplate.execute(sql, new PreparedStatementCallback() { |
| 112 | public Object doInPreparedStatement(PreparedStatement ps) throws SQLException, DataAccessException { |
| 113 | for (Iterator iterator = processed.iterator(); iterator.hasNext();) { |
| 114 | Object item = (Object) iterator.next(); |
| 115 | preparedStatementSetter.setValues(item, ps); |
| 116 | ps.addBatch(); |
| 117 | } |
| 118 | return ps.executeBatch(); |
| 119 | } |
| 120 | }); |
| 121 | } |
| 122 | } |
| 123 | |
| 124 | protected String getResourceKey() { |
| 125 | return ITEMS_PROCESSED; |
| 126 | } |
| 127 | |
| 128 | /** |
| 129 | * No-op. |
| 130 | */ |
| 131 | protected void doWrite(Object output) { |
| 132 | } |
| 133 | |
| 134 | /** |
| 135 | * No-op. |
| 136 | */ |
| 137 | protected void doClear() throws ClearFailedException { |
| 138 | } |
| 139 | |
| 140 | } |