BATCH-1622: add nesting support and test

spring-batch-infrastructure/src/main/java/org/springframework/batch/support/transaction/ResourcelessTransactionManager.java

@@ -16,24 +16,85 @@
 
 package org.springframework.batch.support.transaction;
 
+import java.util.Stack;
+
 import org.springframework.transaction.TransactionDefinition;
 import org.springframework.transaction.TransactionException;
 import org.springframework.transaction.support.AbstractPlatformTransactionManager;
 import org.springframework.transaction.support.DefaultTransactionStatus;
+import org.springframework.transaction.support.TransactionSynchronizationManager;
 
 public class ResourcelessTransactionManager extends AbstractPlatformTransactionManager {
 
 	protected void doBegin(Object transaction, TransactionDefinition definition) throws TransactionException {
+		((ResourcelessTransaction) transaction).begin();
 	}
 
 	protected void doCommit(DefaultTransactionStatus status) throws TransactionException {
+		logger.debug("Committing resourceless transaction on [" + status.getTransaction() + "]");
 	}
 
 	protected Object doGetTransaction() throws TransactionException {
-		return new Object();
+		Object transaction = new ResourcelessTransaction();
+		Stack<Object> resources;
+		if (!TransactionSynchronizationManager.hasResource(this)) {
+			resources = new Stack<Object>();
+			TransactionSynchronizationManager.bindResource(this, resources);
+		}
+		else {
+			@SuppressWarnings("unchecked")
+			Stack<Object> stack = (Stack<Object>) TransactionSynchronizationManager.getResource(this);
+			resources = stack;
+		}
+		resources.push(transaction);
+		return transaction;
 	}
 
 	protected void doRollback(DefaultTransactionStatus status) throws TransactionException {
+		logger.debug("Rolling back resourceless transaction on [" + status.getTransaction() + "]");
+	}
+
+	protected boolean isExistingTransaction(Object transaction) throws TransactionException {
+		if (TransactionSynchronizationManager.hasResource(this)) {
+			@SuppressWarnings("unchecked")
+			Stack<Object> stack = (Stack<Object>) TransactionSynchronizationManager.getResource(this);
+			return stack.size()>1;
+		}
+		return ((ResourcelessTransaction) transaction).isActive();
+	}
+	
+	protected void doSetRollbackOnly(DefaultTransactionStatus status) throws TransactionException {
+	}
+
+	protected void doCleanupAfterCompletion(Object transaction) {
+		@SuppressWarnings("unchecked")
+		Stack<Object> list = (Stack<Object>) TransactionSynchronizationManager.getResource(this);
+		Stack<Object> resources = list;
+		if (!resources.isEmpty()) {
+			resources.pop();
+		}
+		if (resources.isEmpty()) {
+			TransactionSynchronizationManager.unbindResource(this);
+		}
+		((ResourcelessTransaction) transaction).clear();
+	}
+
+	private static class ResourcelessTransaction {
+
+		private boolean active = false;
+
+		public boolean isActive() {
+			return active;
+		}
+
+		public void begin() {
+			active = true;
+		}
+
+		public void clear() {
+			active = false;
+		}
+
 	}
 
 }