RESOLVED - BATCH-828: org.springframework.batch.item.file.MultiResourceItemReader should allow for no resources

graceful handling for non-existing input resources

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/FlatFileItemReader.java

@@ -92,6 +92,8 @@ public class FlatFileItemReader<T> extends AbstractItemReaderItemStream<T> imple
 
 	private LineCallbackHandler headerCallback;
 
+	private boolean noInput;
+
 	public FlatFileItemReader() {
 		setName(ClassUtils.getShortName(FlatFileItemReader.class));
 	}
@@ -213,8 +215,13 @@ public class FlatFileItemReader<T> extends AbstractItemReaderItemStream<T> imple
 	 */
 	protected void doOpen() throws Exception {
 		Assert.notNull(resource, "Input resource must not be null");
-		Assert.state(resource.exists(), "Resource must exist: [" + resource + "]");
 
+		noInput = false;
+		if (!resource.exists()) {
+			noInput = true;
+			log.warn("Input resource does not exist");
+			return;
+		}
 		try {
 			reader = new BufferedReader(new InputStreamReader(resource.getInputStream(), encoding));
 		}
@@ -249,6 +256,9 @@ public class FlatFileItemReader<T> extends AbstractItemReaderItemStream<T> imple
 	 * {@link #setFieldSetMapper(FieldSetMapper)}.
 	 */
 	protected T doRead() throws Exception {
+		if (noInput) {
+			return null;
+		}
 		String record = readRecord();
 
 		if (record != null) {

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/file/MultiResourceItemReader.java

@@ -45,7 +45,7 @@ public class MultiResourceItemReader<T> implements ItemReader<T>, ItemStream {
 	private boolean saveState = true;
 	
 	// signals there are no resources to read -> just return null on first read
-	private boolean emptyInput;
+	private boolean noInput;
 
 	private Comparator<Resource> comparator = new Comparator<Resource>() {
 
@@ -67,7 +67,7 @@ public class MultiResourceItemReader<T> implements ItemReader<T>, ItemStream {
 	 */
 	public T read() throws Exception, UnexpectedInputException, NoWorkFoundException, ParseException {
 
-		if (emptyInput) {
+		if (noInput) {
 			return null;
 		}
 		
@@ -112,7 +112,7 @@ public class MultiResourceItemReader<T> implements ItemReader<T>, ItemStream {
 	public void close(ExecutionContext executionContext) throws ItemStreamException {
 		index = new MultiResourceIndex();
 		delegate.close(new ExecutionContext());
-		emptyInput = false;
+		noInput = false;
 	}
 
 	/**
@@ -123,10 +123,10 @@ public class MultiResourceItemReader<T> implements ItemReader<T>, ItemStream {
 
 		Assert.notNull(resources, "Resources must be set");
 		
-		emptyInput = false;
+		noInput = false;
 		if (resources.length == 0) {
-			logger.info("No resources to read");
-			emptyInput = true;
+			logger.warn("No resources to read");
+			noInput = true;
 			return;
 		}
 

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/xml/StaxEventItemReader.java

@@ -8,6 +8,8 @@ import javax.xml.stream.XMLInputFactory;
 import javax.xml.stream.XMLStreamException;
 import javax.xml.stream.events.StartElement;
 
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
 import org.springframework.batch.item.file.ResourceAwareItemReaderItemStream;
 import org.springframework.batch.item.support.AbstractItemReaderItemStream;
 import org.springframework.batch.item.xml.stax.DefaultFragmentEventReader;
@@ -35,6 +37,8 @@ import org.springframework.xml.transform.StaxSource;
 public class StaxEventItemReader<T> extends AbstractItemReaderItemStream<T> implements
 		ResourceAwareItemReaderItemStream<T>, InitializingBean {
 
+	private static final Log logger = LogFactory.getLog(StaxEventItemReader.class);
+	
 	private FragmentEventReader fragmentReader;
 
 	private XMLEventReader eventReader;
@@ -47,6 +51,8 @@ public class StaxEventItemReader<T> extends AbstractItemReaderItemStream<T> impl
 
 	private String fragmentRootElementName;
 
+	private boolean noInput;
+
 	public StaxEventItemReader() {
 		setName(ClassUtils.getShortName(StaxEventItemReader.class));
 	}
@@ -137,7 +143,13 @@ public class StaxEventItemReader<T> extends AbstractItemReaderItemStream<T> impl
 
 	protected void doOpen() throws Exception {
 		Assert.notNull(resource, "The Resource must not be null.");
-		Assert.state(resource.exists(), "Input resource does not exist: [" + resource + "]");
+		
+		noInput = false;
+		if (!resource.exists()) {
+			noInput = true;
+			logger.warn("Input resource does not exist");
+			return;
+		}
 
 		inputStream = resource.getInputStream();
 		eventReader = XMLInputFactory.newInstance().createXMLEventReader(inputStream);
@@ -149,6 +161,11 @@ public class StaxEventItemReader<T> extends AbstractItemReaderItemStream<T> impl
 	 * Move to next fragment and map it to item.
 	 */
 	protected T doRead() throws Exception {
+		
+		if (noInput) {
+			return null;
+		}
+		
 		T item = null;
 
 		if (moveCursorToNextFragment(fragmentReader)) {

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/file/FlatFileItemReaderBasicTests.java

@@ -16,12 +16,20 @@
 
 package org.springframework.batch.item.file;
 
+import static org.easymock.EasyMock.createStrictMock;
+import static org.easymock.EasyMock.replay;
+import static org.easymock.EasyMock.verify;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+
 import java.io.IOException;
 import java.io.InputStream;
 
-import junit.framework.TestCase;
-import static org.easymock.EasyMock.*;
-
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
 import org.springframework.batch.item.ExecutionContext;
 import org.springframework.batch.item.ItemStreamException;
 import org.springframework.batch.item.ReaderNotOpenException;
@@ -42,7 +50,7 @@ import org.springframework.core.io.Resource;
  * @see FlatFileItemReaderAdvancedTests
  * @author Dave Syer
  */
-public class FlatFileItemReaderBasicTests extends TestCase {
+public class FlatFileItemReaderBasicTests {
 
 	// object under test
 	private FlatFileItemReader<FieldSet> itemReader = new FlatFileItemReader<FieldSet>();
@@ -65,7 +73,8 @@ public class FlatFileItemReaderBasicTests extends TestCase {
 	/**
 	 * Create inputFile, inject mock/stub dependencies for tested object, initialize the tested object
 	 */
-	protected void setUp() throws Exception {
+	@Before
+	public void setUp() throws Exception {
 
 		itemReader.setResource(getInputResource(TEST_STRING));
 		itemReader.setLineTokenizer(tokenizer);
@@ -78,7 +87,8 @@ public class FlatFileItemReaderBasicTests extends TestCase {
 	/**
 	 * Release resources.
 	 */
-	protected void tearDown() throws Exception {
+	@After
+	public void tearDown() throws Exception {
 		itemReader.close(null);
 	}
 
@@ -89,6 +99,7 @@ public class FlatFileItemReaderBasicTests extends TestCase {
 	/**
 	 * Regular usage of <code>read</code> method
 	 */
+	@Test
 	public void testRead() throws Exception {
 		itemReader.open(executionContext);
 		assertEquals("[FlatFileInputTemplate-TestData]", itemReader.read().toString());
@@ -97,6 +108,7 @@ public class FlatFileItemReaderBasicTests extends TestCase {
 	/**
 	 * Regular usage of <code>read</code> method
 	 */
+	@Test
 	public void testReadExhausted() throws Exception {
 		itemReader.open(executionContext);
 		assertEquals("[FlatFileInputTemplate-TestData]", itemReader.read().toString());
@@ -106,6 +118,7 @@ public class FlatFileItemReaderBasicTests extends TestCase {
 	/**
 	 * Regular usage of <code>read</code> method
 	 */
+	@Test
 	public void testReadWithTokenizerError() throws Exception {
 		itemReader.setLineTokenizer(new LineTokenizer() {
 			public FieldSet tokenize(String line) {
@@ -122,6 +135,7 @@ public class FlatFileItemReaderBasicTests extends TestCase {
 		}
 	}
 
+	@Test
 	public void testReadWithMapperError() throws Exception {
 		itemReader.setFieldSetMapper(new FieldSetMapper<FieldSet>() {
 			public FieldSet mapLine(FieldSet fs) {
@@ -139,6 +153,7 @@ public class FlatFileItemReaderBasicTests extends TestCase {
 		}
 	}
 
+	@Test
 	public void testReadBeforeOpen() throws Exception {
 		itemReader = new FlatFileItemReader<FieldSet>();
 		itemReader.setResource(getInputResource(TEST_STRING));
@@ -151,6 +166,7 @@ public class FlatFileItemReaderBasicTests extends TestCase {
 		}
 	}
 
+	@Test
 	public void testCloseBeforeOpen() throws Exception {
 		itemReader = new FlatFileItemReader<FieldSet>();
 		itemReader.setResource(getInputResource(TEST_STRING));
@@ -161,6 +177,7 @@ public class FlatFileItemReaderBasicTests extends TestCase {
 		assertEquals("[FlatFileInputTemplate-TestData]", itemReader.read().toString());
 	}
 
+	@Test
 	public void testInitializationWithNullResource() throws Exception {
 		itemReader = new FlatFileItemReader<FieldSet>();
 		try {
@@ -171,11 +188,13 @@ public class FlatFileItemReaderBasicTests extends TestCase {
 		}
 	}
 
+	@Test
 	public void testOpenTwiceHasNoEffect() throws Exception {
 		itemReader.open(executionContext);
 		testRead();
 	}
 
+	@Test
 	public void testSetValidEncoding() throws Exception {
 		itemReader = new FlatFileItemReader<FieldSet>();
 		itemReader.setEncoding("UTF-8");
@@ -185,6 +204,7 @@ public class FlatFileItemReaderBasicTests extends TestCase {
 		testRead();
 	}
 
+	@Test
 	public void testSetNullEncoding() throws Exception {
 		itemReader = new FlatFileItemReader<FieldSet>();
 		itemReader.setEncoding(null);
@@ -197,6 +217,7 @@ public class FlatFileItemReaderBasicTests extends TestCase {
 		}
 	}
 
+	@Test
 	public void testSetInvalidEncoding() throws Exception {
 		itemReader = new FlatFileItemReader<FieldSet>();
 		itemReader.setEncoding("foo");
@@ -211,16 +232,19 @@ public class FlatFileItemReaderBasicTests extends TestCase {
 		}
 	}
 
+	@Test
 	public void testEncoding() throws Exception {
 		itemReader.setEncoding("UTF-8");
 		testRead();
 	}
 
+	@Test
 	public void testRecordSeparator() throws Exception {
 		itemReader.setRecordSeparatorPolicy(new DefaultRecordSeparatorPolicy());
 		testRead();
 	}
 
+	@Test
 	public void testComments() throws Exception {
 		itemReader.setResource(getInputResource("% Comment\n" + TEST_STRING));
 		itemReader.setComments(new String[] { "%" });
@@ -231,6 +255,7 @@ public class FlatFileItemReaderBasicTests extends TestCase {
 	 * Header line is skipped and used to setup fieldSet column names.
 	 * It is also passed to header callback.
 	 */
+	@Test
 	public void testColumnNamesInHeader() throws Exception {
 		final String INPUT = "name1|name2\nvalue1|value2\nvalue3|value4";
 		
@@ -261,6 +286,7 @@ public class FlatFileItemReaderBasicTests extends TestCase {
 	/**
 	 * Header line is skipped and used to setup fieldSet column names.
 	 */
+	@Test
 	public void testLinesToSkip() throws Exception {
 		final String INPUT = "foo bar spam\none two\nthree four";
 
@@ -281,6 +307,7 @@ public class FlatFileItemReaderBasicTests extends TestCase {
 		assertEquals("four", fs.readString(1));
 	}
 
+	@Test
 	public void testNonExistantResource() throws Exception {
 
 		Resource resource = new NonExistentResource();
@@ -294,15 +321,12 @@ public class FlatFileItemReaderBasicTests extends TestCase {
 		// afterPropertiesSet should only throw an exception if the Resource is null
 		testReader.afterPropertiesSet();
 
-		try {
-			testReader.open(executionContext);
-			fail();
-		} catch (ItemStreamException ex) {
-			// expected
-		}
+		testReader.open(executionContext);
+		assertNull(testReader.read());
 
 	}
 
+	@Test
 	public void testRuntimeFileCreation() throws Exception {
 
 		Resource resource = new NonExistentResource();

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/xml/StaxEventItemReaderTests.java

@@ -13,8 +13,10 @@ import javax.xml.stream.events.EndElement;
 import javax.xml.stream.events.XMLEvent;
 import javax.xml.transform.Source;
 
-import junit.framework.TestCase;
+import static org.junit.Assert.*;
 
+import org.junit.Before;
+import org.junit.Test;
 import org.springframework.batch.item.ExecutionContext;
 import org.springframework.batch.item.ItemStreamException;
 import org.springframework.core.io.AbstractResource;
@@ -30,7 +32,7 @@ import org.springframework.xml.transform.StaxSource;
  * 
  * @author Robert Kasanicky
  */
-public class StaxEventItemReaderTests extends TestCase {
+public class StaxEventItemReaderTests {
 
 	// object under test
 	private StaxEventItemReader<List<XMLEvent>> source;
@@ -44,15 +46,18 @@ public class StaxEventItemReaderTests extends TestCase {
 
 	private ExecutionContext executionContext;
 
-	protected void setUp() throws Exception {
+	@Before
+	public void setUp() throws Exception {
 		this.executionContext = new ExecutionContext();
 		source = createNewInputSouce();
 	}
 
+	@Test
 	public void testAfterPropertiesSet() throws Exception {
 		source.afterPropertiesSet();
 	}
 
+	@Test
 	public void testAfterPropertesSetException() throws Exception {
 
 		source = createNewInputSouce();
@@ -80,6 +85,7 @@ public class StaxEventItemReaderTests extends TestCase {
 	 * Regular usage scenario. ItemReader should pass XML fragments to
 	 * unmarshaller wrapped with StartDocument and EndDocument events.
 	 */
+	@Test
 	public void testFragmentWrapping() throws Exception {
 		source.afterPropertiesSet();
 		source.open(executionContext);
@@ -94,6 +100,7 @@ public class StaxEventItemReaderTests extends TestCase {
 	/**
 	 * Cursor is moved before beginning of next fragment.
 	 */
+	@Test
 	public void testMoveCursorToNextFragment() throws XMLStreamException, FactoryConfigurationError, IOException {
 		Resource resource = new ByteArrayResource(xml.getBytes());
 		XMLEventReader reader = XMLInputFactory.newInstance().createXMLEventReader(resource.getInputStream());
@@ -110,6 +117,7 @@ public class StaxEventItemReaderTests extends TestCase {
 	/**
 	 * Save restart data and restore from it.
 	 */
+	@Test
 	public void testRestart() throws Exception {
 
 		source.open(executionContext);
@@ -126,6 +134,7 @@ public class StaxEventItemReaderTests extends TestCase {
 
 	}
 
+	@Test
 	public void testRestoreWorksFromClosedStream() throws Exception {
 		source.close(executionContext);
 		source.update(executionContext);
@@ -135,6 +144,7 @@ public class StaxEventItemReaderTests extends TestCase {
 	 * Statistics return the current record count. Calling read after end of
 	 * input does not increase the counter.
 	 */
+	@Test
 	public void testExecutionContext() throws Exception {
 		final int NUMBER_OF_RECORDS = 2;
 		source.open(executionContext);
@@ -156,11 +166,13 @@ public class StaxEventItemReaderTests extends TestCase {
 		return executionContext.getLong(ClassUtils.getShortName(StaxEventItemReader.class) + ".read.count");
 	}
 
+	@Test
 	public void testCloseWithoutOpen() throws Exception {
 		source.close(null);
 		// No error!
 	}
 
+	@Test
 	public void testClose() throws Exception {
 		MockStaxEventItemReader newSource = new MockStaxEventItemReader();
 		Resource resource = new ByteArrayResource(xml.getBytes());
@@ -187,6 +199,7 @@ public class StaxEventItemReaderTests extends TestCase {
 		}
 	}
 
+	@Test
 	public void testOpenBadIOInput() {
 
 		source.setResource(new AbstractResource() {
@@ -212,20 +225,19 @@ public class StaxEventItemReaderTests extends TestCase {
 
 	}
 
+	@Test
 	public void testNonExistentResource() throws Exception {
 
 		source.setResource(new NonExistentResource());
 		source.afterPropertiesSet();
 
-		try {
-			source.open(executionContext);
-			fail();
-		}
-		catch (ItemStreamException ex) {
-			// expected
-		}
+		
+		source.open(executionContext);
+		assertNull(source.read());
+		
 	}
 
+	@Test
 	public void testRuntimeFileCreation() throws Exception {
 
 		source.setResource(new NonExistentResource());