OPEN - issue BATCH-771: Refactor Listeners for chunk changes

Add experiments in stateless retry and chunk processing

spring-batch-core/src/test/java/org/springframework/batch/core/step/item/AlmostStatefulRetryChunkTests.java

@@ -35,7 +35,7 @@ import org.junit.runners.Parameterized.Parameters;
  * 
  */
 @RunWith(Parameterized.class)
-public class ChunkTests {
+public class AlmostStatefulRetryChunkTests {
 
 	private enum CallType {
 		RUN, RETRY;
@@ -55,7 +55,7 @@ public class ChunkTests {
 
 	private Object lastCallType;
 
-	public ChunkTests(String[] args, int limit) {
+	public AlmostStatefulRetryChunkTests(String[] args, int limit) {
 		chunk = new Chunk<String>();
 		for (String string : args) {
 			chunk.add(string);
@@ -64,7 +64,7 @@ public class ChunkTests {
 	}
 
 	@Test
-	public void testSimpleScenario() throws Exception {
+	public void testRetry() throws Exception {
 		logger.debug("Starting simple scenario");
 		List<String> items = new ArrayList<String>(chunk.getItems());
 		items.removeAll(Collections.singleton("fail"));
@@ -108,6 +108,7 @@ public class ChunkTests {
 	 */
 	private void retryChunk(Chunk<String> chunk) throws Exception {
 		try {
+			// N.B. a classic stateful retry goes straight to recovery here
 			doWrite(chunk);
 			retryAttempts = 0;
 		}
@@ -117,7 +118,8 @@ public class ChunkTests {
 				retryAttempts = 0;
 				if (chunk.canSkip()) {
 					chunk.getSkippedItem();
-				} else {
+				}
+				else {
 					throw e;
 				}
 			}

spring-batch-core/src/test/java/org/springframework/batch/core/step/item/StatelessRetryChunkTests.java

@@ -0,0 +1,159 @@
+/*
+ * Copyright 2006-2007 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.core.step.item;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+import org.junit.runners.Parameterized.Parameters;
+
+/**
+ * @author Dave Syer
+ * 
+ */
+@RunWith(Parameterized.class)
+public class StatelessRetryChunkTests {
+
+	private Log logger = LogFactory.getLog(getClass());
+
+	private final Chunk<String> chunk;
+
+	private static final int BACKSTOP_LIMIT = 1000;
+
+	private int count = 0;
+	
+	public StatelessRetryChunkTests(String[] args) {
+		chunk = new Chunk<String>();
+		for (String string : args) {
+			chunk.add(string);
+		}
+	}
+
+	@Test
+	public void testRetry() throws Exception {
+
+		logger.debug("Starting simple scenario");
+		List<String> items = new ArrayList<String>(chunk.getItems());
+		int before = items.size();
+		
+		items.removeAll(Collections.singleton("fail"));
+
+		int errors = 0;
+		
+		boolean error = true;
+		while (error && count++ < BACKSTOP_LIMIT) {
+			try {
+				// success
+				logger.debug("Run items: " + chunk.getItems());
+				retryChunk(chunk);
+				error = false;
+			}
+			catch (SpecialException e) {
+				error = true;
+			}
+			catch (Exception e) {
+				errors++;
+				error = true;
+			}
+		}
+
+		logger.debug("Items: " + chunk.getItems());
+		
+		assertTrue("Backstop reached.  Probably an infinite loop...", count < BACKSTOP_LIMIT);
+		assertFalse(chunk.getItems().contains("fail"));
+		assertEquals(items, chunk.getItems());
+
+		int after = chunk.getItems().size();
+		logger.debug(String.format("Error count: %d, size before: %d, size after: %d", errors, before, after));
+
+	}
+
+	/**
+	 * @param chunk
+	 * @throws Exception
+	 */
+	private void retryChunk(Chunk<String> chunk) throws Exception {
+		boolean complete = chunk.isComplete();
+		try {
+			doWrite(chunk);
+		}
+		catch (Exception e) {
+			if (chunk.canSkip()) {
+				chunk.getSkippedItem();
+			}
+			else {
+				if (complete) {
+					chunk.rethrow(e);
+				} else {
+					chunk.rethrow(new SpecialException());
+				}
+			}
+		}
+		chunk.rethrow();
+	}
+
+	/**
+	 * @param chunk
+	 * @throws Exception
+	 */
+	private void doWrite(Chunk<String> chunk) throws Exception {
+		List<String> items = chunk.getItems();
+		if (items.contains("fail")) {
+			throw new Exception();
+		}
+	}
+
+	@Parameters
+	public static List<Object[]> data() {
+		List<Object[]> params = new ArrayList<Object[]>();
+		params.add(new Object[] { new String[] { "foo" } });
+		params.add(new Object[] { new String[] { "foo", "bar" } });
+		params.add(new Object[] { new String[] { "foo", "bar", "spam" } });
+		params.add(new Object[] { new String[] { "foo", "bar", "spam", "maps", "rab", "oof" } });
+		params.add(new Object[] { new String[] { "fail" } });
+		params.add(new Object[] { new String[] { "foo", "fail" } });
+		params.add(new Object[] { new String[] { "fail", "bar" } });
+		params.add(new Object[] { new String[] { "foo", "fail", "spam" } });
+		params.add(new Object[] { new String[] { "fail", "bar", "spam" } });
+		params.add(new Object[] { new String[] { "foo", "fail", "spam", "maps", "rab", "oof" } });
+		params.add(new Object[] { new String[] { "foo", "fail", "spam", "fail", "rab", "oof" } });
+		params.add(new Object[] { new String[] { "fail", "bar", "spam", "fail", "rab", "oof" } });
+		params.add(new Object[] { new String[] { "foo", "fail", "fail", "fail", "rab", "oof" } });
+		params.add(new Object[] { new String[] { "fail" } });
+		params.add(new Object[] { new String[] { "foo", "fail", "fail", "fail", "rab", "oof" } });
+		params.add(new Object[] { new String[] { "foo", "fail", "fail", "fail", "rab", "oof" } });
+		return params;
+	}
+
+	/**
+	 * @author Dave Syer
+	 *
+	 */
+	public class SpecialException extends Exception {
+
+	}
+
+}