BATCH-1103: Added partitioning sample

spring-batch-core/src/main/java/org/springframework/batch/core/listener/StepListenerFactoryBean.java

@@ -78,7 +78,7 @@ public class StepListenerFactoryBean implements FactoryBean, InitializingBean{
 		
 		Set<Class<? extends StepListener>> listenerInterfaces = new HashSet<Class<? extends StepListener>>();
 		
-		//For every entry in th emap, try and find a method by interface, name, or annotation.  If the same
+		//For every entry in the map, try and find a method by interface, name, or annotation.  If the same
 		for(Entry<String, String> entry : metaDataMap.entrySet()){
 			StepListenerMetaData metaData = StepListenerMetaData.fromPropertyName(entry.getKey());
 			Set<MethodInvoker> invokers = new NullIgnoringSet<MethodInvoker>();

spring-batch-core/src/main/java/org/springframework/batch/core/partition/support/MultiResourcePartitioner.java

@@ -0,0 +1,89 @@
+/*
+ * 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.partition.support;
+
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.springframework.batch.item.ExecutionContext;
+import org.springframework.core.io.Resource;
+import org.springframework.util.Assert;
+
+/**
+ * Implementation of {@link Partitioner} that locates multiple resources and
+ * associates their file names with execution context keys. Creates an
+ * {@link ExecutionContext} per resource, and labels them as
+ * <code>{partition0, partition1, ..., partitionN}</code>. The grid size is
+ * ignored.
+ * 
+ * @author Dave Syer
+ * 
+ */
+public class MultiResourcePartitioner implements Partitioner {
+
+	private static final String DEFAULT_KEY_NAME = "fileName";
+
+	private static final String PARTITION_KEY = "partition";
+
+	private Resource[] resources = new Resource[0];
+
+	private String keyName = DEFAULT_KEY_NAME;
+
+	/**
+	 * The resources to assign to each partition. In Spring configuration you
+	 * can use a pattern to select multiple resources.
+	 * @param resources the resources to use
+	 */
+	public void setResources(Resource[] resources) {
+		this.resources = resources;
+	}
+
+	/**
+	 * The name of the key for the file name in each {@link ExecutionContext}.
+	 * Defaults to "fileName".
+	 * @param keyName the value of the key
+	 */
+	public void setKeyName(String keyName) {
+		this.keyName = keyName;
+	}
+
+	/**
+	 * Assign the filename of each of the injected resources to an
+	 * {@link ExecutionContext}.
+	 * 
+	 * @see Partitioner#partition(int)
+	 */
+	public Map<String, ExecutionContext> partition(int gridSize) {
+		Map<String, ExecutionContext> map = new HashMap<String, ExecutionContext>(gridSize);
+		int i = 0;
+		for (Resource resource : resources) {
+			ExecutionContext context = new ExecutionContext();
+			Assert.state(resource.exists(), "Resource does not exist: "+resource);
+			try {
+				context.putString(keyName, resource.getURL().toExternalForm());
+			}
+			catch (IOException e) {
+				throw new IllegalArgumentException("File could not be located for: "+resource, e);
+			}
+			map.put(PARTITION_KEY + i, context);
+			i++;
+		}
+		return map;
+	}
+
+}

spring-batch-core/src/test/java/org/springframework/batch/core/partition/support/MultiResourcePartitionerTests.java

@@ -0,0 +1,54 @@
+package org.springframework.batch.core.partition.support;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+import java.util.Map;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.springframework.batch.item.ExecutionContext;
+import org.springframework.core.io.FileSystemResource;
+import org.springframework.core.io.Resource;
+import org.springframework.core.io.UrlResource;
+import org.springframework.core.io.support.ResourceArrayPropertyEditor;
+
+public class MultiResourcePartitionerTests {
+
+	private MultiResourcePartitioner partitioner = new MultiResourcePartitioner();
+
+	@Before
+	public void setUp() {
+		ResourceArrayPropertyEditor editor = new ResourceArrayPropertyEditor();
+		editor.setAsText("classpath:log4j*");
+		partitioner.setResources((Resource[]) editor.getValue());
+	}
+
+	@Test(expected = IllegalStateException.class)
+	public void testMissingResource() {
+		partitioner.setResources(new Resource[] { new FileSystemResource("does-not-exist") });
+		partitioner.partition(0);
+	}
+
+	@Test
+	public void testPartitionSizeAndKey() {
+		Map<String, ExecutionContext> partition = partitioner.partition(0);
+		assertEquals(1, partition.size());
+		assertTrue(partition.containsKey("partition0"));
+	}
+
+	@Test
+	public void testReadFile() throws Exception {
+		Map<String, ExecutionContext> partition = partitioner.partition(0);
+		String url = partition.get("partition0").getString("fileName");
+		assertTrue(new UrlResource(url).exists());
+	}
+
+	@Test
+	public void testSetKeyName() {
+		partitioner.setKeyName("foo");
+		Map<String, ExecutionContext> partition = partitioner.partition(0);
+		assertTrue(partition.get("partition0").containsKey("foo"));
+	}
+
+}