IN PROGRESS - BATCH-520: Add a Delegating File Reader For Multiple Files

added MultiResourceReader (can be used both with FlatFileItemReader or StaxEventItemReader)

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

@@ -0,0 +1,156 @@
+package org.springframework.batch.item;
+
+import junit.framework.TestCase;
+
+import org.easymock.MockControl;
+import org.springframework.batch.item.file.FlatFileItemReader;
+import org.springframework.batch.item.file.mapping.FieldSet;
+import org.springframework.batch.item.file.mapping.PassThroughFieldSetMapper;
+import org.springframework.core.io.ByteArrayResource;
+import org.springframework.core.io.Resource;
+import org.springframework.core.io.support.ResourcePatternResolver;
+
+/**
+ * Tests for {@link MultiResourceItemReader}.
+ */
+public class MultiResourceItemReaderIntegrationTests extends TestCase {
+
+	private static final String PATTERN = "resource location pattern";
+
+	private MultiResourceItemReader tested = new MultiResourceItemReader();
+
+	private FlatFileItemReader itemReader = new FlatFileItemReader();
+
+	private ExecutionContext ctx = new ExecutionContext();
+
+	// test input spans several resources
+	private Resource r1 = new ByteArrayResource("1\n2\n3\n".getBytes());
+
+	private Resource r2 = new ByteArrayResource("4\n5\n".getBytes());
+
+	private Resource r3 = new ByteArrayResource("".getBytes());
+
+	private Resource r4 = new ByteArrayResource("6\n".getBytes());
+
+	private Resource r5 = new ByteArrayResource("7\n8\n".getBytes());
+
+	/**
+	 * Setup the tested reader to read from the test resources.
+	 */
+	protected void setUp() throws Exception {
+
+		MockControl control = MockControl.createStrictControl(ResourcePatternResolver.class);
+		ResourcePatternResolver resolver = (ResourcePatternResolver) control.getMock();
+		resolver.getResources(PATTERN);
+		control.setReturnValue(new Resource[] { r1, r2, r3, r4, r5 }, 2);
+		control.replay();
+
+		itemReader.setFieldSetMapper(new PassThroughFieldSetMapper());
+
+		tested.setResourcePatternResolver(resolver);
+		tested.setDelegate(itemReader);
+		tested.setResourceLocationPattern(PATTERN);
+		tested.afterPropertiesSet();
+	}
+
+	/**
+	 * Read input from start to end.
+	 */
+	public void testRead() throws Exception {
+
+		tested.open(ctx);
+
+		assertEquals("1", readItem());
+		assertEquals("2", readItem());
+		assertEquals("3", readItem());
+		assertEquals("4", readItem());
+		assertEquals("5", readItem());
+		assertEquals("6", readItem());
+		assertEquals("7", readItem());
+		assertEquals("8", readItem());
+		assertEquals(null, readItem());
+
+		tested.close(ctx);
+	}
+
+	/**
+	 * Read items with a couple of rollbacks, requiring to jump back to items
+	 * from previous resources.
+	 */
+	public void testReset() throws Exception {
+
+		tested.open(ctx);
+
+		assertEquals("1", readItem());
+
+		tested.mark();
+
+		assertEquals("2", readItem());
+		assertEquals("3", readItem());
+
+		tested.reset();
+
+		assertEquals("2", readItem());
+		assertEquals("3", readItem());
+		assertEquals("4", readItem());
+
+		tested.reset();
+
+		assertEquals("2", readItem());
+		assertEquals("3", readItem());
+		assertEquals("4", readItem());
+		assertEquals("5", readItem());
+
+		tested.mark();
+
+		assertEquals("6", readItem());
+		assertEquals("7", readItem());
+
+		tested.reset();
+
+		assertEquals("6", readItem());
+		assertEquals("7", readItem());
+
+		assertEquals("8", readItem());
+		assertEquals(null, readItem());
+
+		tested.close(ctx);
+	}
+
+	/**
+	 * Restore from saved state.
+	 */
+	public void testRestart() throws Exception {
+
+		itemReader.setSaveState(true);
+
+		tested.open(ctx);
+
+		assertEquals("1", readItem());
+		assertEquals("2", readItem());
+		assertEquals("3", readItem());
+		assertEquals("4", readItem());
+
+		tested.update(ctx);
+
+		assertEquals("5", readItem());
+		assertEquals("6", readItem());
+
+		tested.close(ctx);
+
+		tested.open(ctx);
+
+		assertEquals("5", readItem());
+		assertEquals("6", readItem());
+		assertEquals("7", readItem());
+		assertEquals("8", readItem());
+		assertEquals(null, readItem());
+	}
+
+	private String readItem() throws Exception {
+		Object result = tested.read();
+		return result == null ? null : ((FieldSet) result).readString(0);
+
+	}
+
+}