OPEN - issue BATCH-364: StepScope responsibilities can be assumed by Step (not ApplicationContext)

http://jira.springframework.org/browse/BATCH-364

Make StreamManager responsible for calling open() and close().

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/reader/AggregateItemReader.java

@@ -37,13 +37,11 @@ import org.springframework.batch.item.ItemReader;
  * @author Dave Syer
  * 
  */
-public class AggregateItemReader extends AbstractItemReader {
+public class AggregateItemReader extends DelegatingItemReader {
 
 	private static final Log log = LogFactory
 			.getLog(AggregateItemReader.class);
 
-	private ItemReader inputSource;
-
 	/**
 	 * Marker for the end of a multi-object record.
 	 */
@@ -63,7 +61,7 @@ public class AggregateItemReader extends AbstractItemReader {
 	public Object read() throws Exception {
 		ResultHolder holder = new ResultHolder();
 
-		while (process(inputSource.read(), holder)) {
+		while (process(getItemReader().read(), holder)) {
 			continue;
 		}
 
@@ -100,16 +98,6 @@ public class AggregateItemReader extends AbstractItemReader {
 		return true;
 	}
 
-	/**
-	 * Injection setter for {@link ItemReader}.
-	 * 
-	 * @param inputSource
-	 *            an {@link ItemReader}.
-	 */
-	public void setItemReader(ItemReader inputSource) {
-		this.inputSource = inputSource;
-	}
-
 	/**
 	 * Private class for temporary state management while item is being
 	 * collected.

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/reader/DelegatingItemReader.java

@@ -28,7 +28,7 @@ import org.springframework.util.Assert;
  * Simple wrapper around {@link ItemReader}. The input source is expected to
  * take care of open and close operations. If necessary it should be registered
  * as a step scoped bean to ensure that the lifecycle methods are called.
- *
+ * 
  * @author Dave Syer
  */
 public class DelegatingItemReader extends AbstractItemReader implements Skippable, InitializingBean, ItemStream {
@@ -38,9 +38,10 @@ public class DelegatingItemReader extends AbstractItemReader implements Skippabl
 	public void afterPropertiesSet() throws Exception {
 		Assert.notNull(inputSource, "ItemReader must not be null.");
 	}
+
 	/**
 	 * Get the next object from the input source.
-	 * @throws Exception 
+	 * @throws Exception
 	 * @see org.springframework.batch.item.ItemReader#read()
 	 */
 	public Object read() throws Exception {
@@ -53,9 +54,10 @@ public class DelegatingItemReader extends AbstractItemReader implements Skippabl
 	 * {@link ItemStream}.
 	 */
 	public ExecutionContext getExecutionContext() {
-		// TODO: this is not necessary...
-		Assert.state(inputSource instanceof ItemStream, "Input source is not ItemStream");
-		return ((ItemStream) inputSource).getExecutionContext();
+		if (inputSource instanceof ItemStream) {
+			return ((ItemStream) inputSource).getExecutionContext();
+		}
+		return new ExecutionContext();
 	}
 
 	/**
@@ -64,8 +66,9 @@ public class DelegatingItemReader extends AbstractItemReader implements Skippabl
 	 * {@link ItemStream}.
 	 */
 	public void restoreFrom(ExecutionContext data) {
-		Assert.state(inputSource instanceof ItemStream, "Input source is not ItemStream");
-		((ItemStream) inputSource).restoreFrom(data);
+		if (inputSource instanceof ItemStream) {
+			((ItemStream) inputSource).restoreFrom(data);
+		}
 	}
 
 	/**
@@ -82,11 +85,12 @@ public class DelegatingItemReader extends AbstractItemReader implements Skippabl
 
 	public void skip() {
 		if (inputSource instanceof Skippable) {
-			((Skippable)inputSource).skip();
+			((Skippable) inputSource).skip();
 		}
 	}
-	
-	/* (non-Javadoc)
+
+	/*
+	 * (non-Javadoc)
 	 * @see org.springframework.batch.item.ItemStream#open()
 	 */
 	public void open() throws StreamException {
@@ -95,7 +99,8 @@ public class DelegatingItemReader extends AbstractItemReader implements Skippabl
 		}
 	}
 
-	/* (non-Javadoc)
+	/*
+	 * (non-Javadoc)
 	 * @see org.springframework.batch.item.ItemStream#open()
 	 */
 	public void close() throws StreamException {
@@ -116,7 +121,8 @@ public class DelegatingItemReader extends AbstractItemReader implements Skippabl
 		return false;
 	}
 
-	/* (non-Javadoc)
+	/*
+	 * (non-Javadoc)
 	 * @see org.springframework.batch.item.ItemStream#mark(org.springframework.batch.item.ExecutionContext)
 	 */
 	public void mark() {
@@ -125,7 +131,8 @@ public class DelegatingItemReader extends AbstractItemReader implements Skippabl
 		}
 	}
 
-	/* (non-Javadoc)
+	/*
+	 * (non-Javadoc)
 	 * @see org.springframework.batch.item.ItemStream#reset(org.springframework.batch.item.ExecutionContext)
 	 */
 	public void reset() {

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/stream/SimpleStreamManager.java

@@ -116,7 +116,7 @@ public class SimpleStreamManager implements StreamManager {
 	 * @see org.springframework.batch.item.stream.StreamManager#register(java.lang.Object,
 	 * org.springframework.batch.item.ItemStream, ExecutionContext)
 	 */
-	public void register(Object key, ItemStream stream, ExecutionContext executionContext) {
+	public void register(Object key, ItemStream stream) {
 		synchronized (registry) {
 			Set set = (Set) registry.get(key);
 			if (set == null) {
@@ -125,9 +125,19 @@ public class SimpleStreamManager implements StreamManager {
 			}
 			set.add(stream);
 		}
+	}
+	
+	/* (non-Javadoc)
+	 * @see org.springframework.batch.item.stream.StreamManager#restoreFrom(java.lang.Object, org.springframework.batch.item.ExecutionAttributes)
+	 */
+	public void restoreFrom(Object key, final ExecutionContext executionContext) {
 		if (executionContext != null) {
-			stream.restoreFrom(extract(stream, executionContext));
-		}
+			iterate(key, new Callback() {
+				public void execute(ItemStream stream) {
+					stream.restoreFrom(extract(stream, executionContext));
+				}
+			});
+		}	
 	}
 
 	/**
@@ -153,7 +163,7 @@ public class SimpleStreamManager implements StreamManager {
 
 	/**
 	 * Broadcast the call to close from this {@link StreamManager}.
-	 * @throws Exception
+	 * @throws StreamException
 	 */
 	public void close(Object key) throws StreamException {
 		iterate(key, new Callback() {
@@ -163,6 +173,18 @@ public class SimpleStreamManager implements StreamManager {
 		});
 	}
 
+	/**
+	 * Broadcast the call to open from this {@link StreamManager}.
+	 * @throws StreamException
+	 */
+	public void open(Object key) throws StreamException {
+		iterate(key, new Callback() {
+			public void execute(ItemStream stream) {
+				stream.open();
+			}
+		});
+	}
+
 	/**
 	 * Delegate to the {@link PlatformTransactionManager} to create a new
 	 * transaction.

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/stream/StreamManager.java

@@ -37,9 +37,8 @@ public interface StreamManager {
 	 * 
 	 * @param key the key under which to add the provider
 	 * @param stream an {@link ItemStream}
-	 * @param executionContext the context (may be null) to restore from on registration
 	 */
-	void register(Object key, ItemStream stream, ExecutionContext executionContext);
+	void register(Object key, ItemStream stream);
 
 	/**
 	 * Extract and aggregate the {@link ExecutionContext} from all streams under
@@ -60,6 +59,15 @@ public interface StreamManager {
 	 * been registered.
 	 */
 	void close(Object key) throws StreamException;
+
+	/**
+	 * If any resources are needed for the stream to operate they need to be
+	 * opened here.
+	 * 
+	 * @param key the key under which {@link ItemStream} instances might have
+	 * been registered.
+	 */
+	void open(Object key) throws StreamException;
 	
 	TransactionStatus getTransaction(Object key);
 	
@@ -67,4 +75,12 @@ public interface StreamManager {
 	
 	void rollback(TransactionStatus transaction);
 
+	/**
+	 * Restore the streams registered under a goven key.
+	 * 
+	 * @param key the key under which the streams are stored 
+	 * @param executionContext the context (may be null) to restore from
+	 */
+	void restoreFrom(Object key, ExecutionContext executionContext);
+
 }