Java tutorial
/* * 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.batch.item.database; import static org.junit.Assert.assertEquals; import static org.junit.Assert.assertNotNull; import java.sql.ResultSet; import java.sql.SQLException; import java.util.ArrayList; import java.util.HashSet; import java.util.LinkedHashMap; import java.util.List; import java.util.Map; import java.util.Set; import java.util.concurrent.Callable; import java.util.concurrent.CompletionService; import java.util.concurrent.ExecutionException; import java.util.concurrent.ExecutorCompletionService; import java.util.concurrent.Executors; import javax.sql.DataSource; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.junit.After; import org.junit.Before; import org.junit.Test; import org.junit.runner.RunWith; import org.springframework.batch.item.ItemReader; import org.springframework.batch.item.database.support.SqlPagingQueryProviderFactoryBean; import org.springframework.batch.item.sample.Foo; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.jdbc.core.JdbcTemplate; import org.springframework.jdbc.core.RowMapper; import org.springframework.test.context.ContextConfiguration; import org.springframework.test.context.junit4.SpringJUnit4ClassRunner; import org.springframework.test.jdbc.JdbcTestUtils; /** * @author Dave Syer * @author David Thexton * @author Michael Minella */ @RunWith(SpringJUnit4ClassRunner.class) @ContextConfiguration(locations = "JdbcPagingItemReaderCommonTests-context.xml") public class JdbcPagingItemReaderAsyncTests { /** * The page size */ private static final int PAGE_SIZE = 10; /** * The number of items to read */ private static final int ITEM_COUNT = 1000; /** * The number of threads to create */ private static final int THREAD_COUNT = 10; private static Log logger = LogFactory.getLog(JdbcPagingItemReaderAsyncTests.class); @Autowired private DataSource dataSource; private int maxId; @Before public void init() { JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource); Integer tempMaxId = jdbcTemplate.queryForObject("SELECT MAX(ID) from T_FOOS", Integer.class); maxId = tempMaxId != null ? tempMaxId : 0; for (int i = ITEM_COUNT; i > maxId; i--) { jdbcTemplate.update("INSERT into T_FOOS (ID,NAME,VALUE) values (?, ?, ?)", i, "foo" + i, i); } assertEquals(ITEM_COUNT, JdbcTestUtils.countRowsInTable(jdbcTemplate, "T_FOOS")); } @After public void destroy() { JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource); jdbcTemplate.update("DELETE from T_FOOS where ID>?", maxId); } @Test public void testAsyncReader() throws Throwable { List<Throwable> throwables = new ArrayList<Throwable>(); int max = 10; for (int i = 0; i < max; i++) { try { doTest(); } catch (Throwable e) { throwables.add(e); } } if (!throwables.isEmpty()) { throw new IllegalStateException(String.format("Failed %d out of %d", throwables.size(), max), throwables.get(0)); } } /** * @throws Exception * @throws InterruptedException * @throws ExecutionException */ private void doTest() throws Exception, InterruptedException, ExecutionException { final ItemReader<Foo> reader = getItemReader(); CompletionService<List<Foo>> completionService = new ExecutorCompletionService<List<Foo>>( Executors.newFixedThreadPool(THREAD_COUNT)); for (int i = 0; i < THREAD_COUNT; i++) { completionService.submit(new Callable<List<Foo>>() { @Override public List<Foo> call() throws Exception { List<Foo> list = new ArrayList<Foo>(); Foo next = null; do { next = reader.read(); Thread.sleep(10L); logger.debug("Reading item: " + next); if (next != null) { list.add(next); } } while (next != null); return list; } }); } int count = 0; Set<Foo> results = new HashSet<Foo>(); for (int i = 0; i < THREAD_COUNT; i++) { List<Foo> items = completionService.take().get(); count += items.size(); logger.debug("Finished items count: " + items.size()); logger.debug("Finished items: " + items); assertNotNull(items); results.addAll(items); } assertEquals(ITEM_COUNT, count); assertEquals(ITEM_COUNT, results.size()); } protected ItemReader<Foo> getItemReader() throws Exception { JdbcPagingItemReader<Foo> reader = new JdbcPagingItemReader<Foo>(); reader.setDataSource(dataSource); SqlPagingQueryProviderFactoryBean factory = new SqlPagingQueryProviderFactoryBean(); factory.setDataSource(dataSource); factory.setSelectClause("select ID, NAME, VALUE"); factory.setFromClause("from T_FOOS"); Map<String, Order> sortKeys = new LinkedHashMap<String, Order>(); sortKeys.put("VALUE", Order.ASCENDING); factory.setSortKeys(sortKeys); reader.setQueryProvider(factory.getObject()); reader.setRowMapper(new RowMapper<Foo>() { @Override public Foo mapRow(ResultSet rs, int i) throws SQLException { Foo foo = new Foo(); foo.setId(rs.getInt(1)); foo.setName(rs.getString(2)); foo.setValue(rs.getInt(3)); return foo; } }); reader.setPageSize(PAGE_SIZE); reader.afterPropertiesSet(); reader.setSaveState(false); return reader; } }