IN PROGRESS - issue BATCH-7: Remove transaction synchronization and state management from input/output sources (formerly buffering)

http://jira.springframework.org/browse/BATCH-7

Remove some references to Statistics

spring-batch-core/src/main/java/org/springframework/batch/core/domain/StepContribution.java

@@ -15,7 +15,7 @@
  */
 package org.springframework.batch.core.domain;
 
-import java.util.Properties;
+import org.springframework.batch.item.StreamContext;
 
 /**
  * Represents a contribution to a {@link StepExecution}, buffering changes
@@ -30,7 +30,7 @@ public class StepContribution {
 
 	private StepExecution execution;
 
-	private Properties statistics;
+	private StreamContext streamContext;
 
 	private int commitCount;
 
@@ -57,15 +57,6 @@ public class StepContribution {
 		return taskCount;
 	}
 
-	/**
-	 * Set the statistics properties.
-	 * 
-	 * @param statistics
-	 */
-	public void setStatistics(Properties statistics) {
-		this.statistics = statistics;
-	}
-
 	/**
 	 * Increment the commit counter.
 	 */
@@ -74,11 +65,20 @@ public class StepContribution {
 	}
 
 	/**
-	 * Public getter for the statistics.
-	 * @return the statistics
+	 * Set the statistics properties.
+	 * 
+	 * @param streamContext
 	 */
-	public Properties getStatistics() {
-		return statistics;
+	public void setStreamContext(StreamContext streamContext) {
+		this.streamContext = streamContext;
+	}
+
+	/**
+	 * Public getter for the {@link StreamContext}.
+	 * @return the stream context
+	 */
+	public StreamContext getStreamContext() {
+		return streamContext;
 	}
 
 	/**

spring-batch-core/src/main/java/org/springframework/batch/core/domain/StepExecution.java

@@ -17,8 +17,8 @@
 package org.springframework.batch.core.domain;
 
 import java.util.Date;
-import java.util.Properties;
 
+import org.springframework.batch.item.StreamContext;
 import org.springframework.batch.repeat.ExitStatus;
 
 /**
@@ -51,7 +51,7 @@ public class StepExecution extends Entity {
 
 	private Date endTime = null;
 
-	private Properties statistics = new Properties();
+	private StreamContext streamContext = new StreamContext();
 
 	private ExitStatus exitStatus = ExitStatus.UNKNOWN;
 
@@ -88,12 +88,12 @@ public class StepExecution extends Entity {
 		taskCount++;
 	}
 
-	public Properties getStatistics() {
-		return statistics;
+	public StreamContext getStreamContext() {
+		return streamContext;
 	}
 
-	public void setStatistics(Properties statistics) {
-		this.statistics = statistics;
+	public void setStreamContext(StreamContext statistics) {
+		this.streamContext = statistics;
 	}
 
 	public Integer getCommitCount() {
@@ -249,7 +249,7 @@ public class StepExecution extends Entity {
 	 */
 	public synchronized void apply(StepContribution contribution) {
 		taskCount += contribution.getTaskCount();
-		statistics = contribution.getStatistics();
+		streamContext = contribution.getStreamContext();
 		commitCount += contribution.getCommitCount();
 	}
 

spring-batch-core/src/test/java/org/springframework/batch/core/domain/StepContributionTests.java

@@ -17,18 +17,23 @@ package org.springframework.batch.core.domain;
 
 import junit.framework.TestCase;
 
+import org.springframework.batch.item.StreamContext;
+import org.springframework.batch.item.stream.GenericStreamContext;
 import org.springframework.batch.support.PropertiesConverter;
 
 /**
  * @author Dave Syer
- *
+ * 
  */
 public class StepContributionTests extends TestCase {
 
 	private StepExecution execution = new StepExecution();
+
 	private StepContribution contribution = new StepContribution(execution);
+
 	/**
-	 * Test method for {@link org.springframework.batch.core.domain.StepContribution#incrementTaskCount()}.
+	 * Test method for
+	 * {@link org.springframework.batch.core.domain.StepContribution#incrementTaskCount()}.
 	 */
 	public void testIncrementTaskCount() {
 		assertEquals(0, contribution.getTaskCount());
@@ -37,16 +42,18 @@ public class StepContributionTests extends TestCase {
 	}
 
 	/**
-	 * Test method for {@link org.springframework.batch.core.domain.StepContribution#setStatistics(java.util.Properties)}.
+	 * Test method for
+	 * {@link org.springframework.batch.core.domain.StepContribution#setStreamContext(StreamContext)}.
 	 */
 	public void testSetStatistics() {
-		assertEquals(null, contribution.getStatistics());
-		contribution.setStatistics(PropertiesConverter.stringToProperties("foo=bar"));
-		assertEquals(1, contribution.getStatistics().size());
+		assertEquals(null, contribution.getStreamContext());
+		contribution.setStreamContext(new GenericStreamContext(PropertiesConverter.stringToProperties("foo=bar")));
+		assertEquals(1, contribution.getStreamContext().getProperties().size());
 	}
 
 	/**
-	 * Test method for {@link org.springframework.batch.core.domain.StepContribution#incrementCommitCount()}.
+	 * Test method for
+	 * {@link org.springframework.batch.core.domain.StepContribution#incrementCommitCount()}.
 	 */
 	public void testIncrementCommitCount() {
 		assertEquals(0, contribution.getCommitCount());
@@ -55,7 +62,8 @@ public class StepContributionTests extends TestCase {
 	}
 
 	/**
-	 * Test method for {@link org.springframework.batch.core.domain.StepContribution#isTerminateOnly()}.
+	 * Test method for
+	 * {@link org.springframework.batch.core.domain.StepContribution#isTerminateOnly()}.
 	 */
 	public void testIsTerminateOnly() {
 		assertFalse(contribution.isTerminateOnly());

spring-batch-core/src/test/java/org/springframework/batch/core/domain/StepExecutionTests.java

@@ -16,10 +16,10 @@
 package org.springframework.batch.core.domain;
 
 import java.util.Date;
-import java.util.Properties;
 
 import junit.framework.TestCase;
 
+import org.springframework.batch.item.StreamContext;
 import org.springframework.batch.repeat.ExitStatus;
 
 /**
@@ -199,13 +199,11 @@ public class StepExecutionTests extends TestCase {
 	}
 
 	public void testStatistics() throws Exception {
-		assertNotNull(execution.getStatistics());
-		execution.setStatistics(new Properties() {
-			{
-				setProperty("foo", "bar");
-			}
-		});
-		assertEquals("bar", execution.getStatistics().getProperty("foo"));
+		assertNotNull(execution.getStreamContext());
+		StreamContext context = new StreamContext();
+		context.putString("foo", "bar");
+		execution.setStreamContext(context );
+		assertEquals("bar", execution.getStreamContext().getString("foo"));
 	}
 
 	public void testEqualsWithSameIdentifier() throws Exception {

spring-batch-execution/src/main/java/org/springframework/batch/execution/bootstrap/support/SimpleExportedJobLauncher.java

@@ -103,7 +103,7 @@ public class SimpleExportedJobLauncher implements ExportedJobLauncher, Initializ
 		int i = 0;
 		for (Iterator iterator = execution.getStepExecutions().iterator(); iterator.hasNext();) {
 			StepExecution stepExecution = (StepExecution) iterator.next();
-			Properties statistics = stepExecution.getStatistics();
+			Properties statistics = stepExecution.getStreamContext().getProperties();
 			for (Iterator iter = statistics.keySet().iterator(); iter.hasNext();) {
 				String key = (String) iter.next();
 				result.setProperty(prefix + "step" + i + "." + key, statistics.getProperty(key));

spring-batch-execution/src/main/java/org/springframework/batch/execution/repository/dao/JdbcStepDao.java

@@ -161,7 +161,9 @@ public class JdbcStepDao implements StepDao, InitializingBean {
 
 				StepInstance step = new StepInstance(new Long(rs.getLong(1)));
 				step.setStatus(BatchStatus.getStatus(rs.getString(2)));
-				step.setStreamContext(new GenericStreamContext(PropertiesConverter.stringToProperties(rs.getString(3))));
+				step
+						.setStreamContext(new GenericStreamContext(PropertiesConverter.stringToProperties(rs
+								.getString(3))));
 				return step;
 			}
 
@@ -211,7 +213,8 @@ public class JdbcStepDao implements StepDao, InitializingBean {
 				stepExecution.setStatus(BatchStatus.getStatus(rs.getString(5)));
 				stepExecution.setCommitCount(rs.getInt(6));
 				stepExecution.setTaskCount(rs.getInt(7));
-				stepExecution.setStatistics(PropertiesConverter.stringToProperties(rs.getString(8)));
+				stepExecution.setStreamContext(new GenericStreamContext(PropertiesConverter.stringToProperties(rs
+						.getString(8))));
 				stepExecution.setExitStatus(new ExitStatus("Y".equals(rs.getString(9)), rs.getString(10), rs
 						.getString(11)));
 				return stepExecution;
@@ -243,7 +246,9 @@ public class JdbcStepDao implements StepDao, InitializingBean {
 				StepInstance step = new StepInstance(job, rs.getString(2), new Long(rs.getLong(1)));
 				String status = rs.getString(3);
 				step.setStatus(BatchStatus.getStatus(status));
-				step.setStreamContext(new GenericStreamContext(PropertiesConverter.stringToProperties(rs.getString(3))));
+				step
+						.setStreamContext(new GenericStreamContext(PropertiesConverter.stringToProperties(rs
+								.getString(3))));
 				return step;
 			}
 		};
@@ -312,7 +317,8 @@ public class JdbcStepDao implements StepDao, InitializingBean {
 		Object[] parameters = new Object[] { stepExecution.getId(), stepExecution.getVersion(),
 				stepExecution.getStepId(), stepExecution.getJobExecutionId(), stepExecution.getStartTime(),
 				stepExecution.getEndTime(), stepExecution.getStatus().toString(), stepExecution.getCommitCount(),
-				stepExecution.getTaskCount(), PropertiesConverter.propertiesToString(stepExecution.getStatistics()),
+				stepExecution.getTaskCount(),
+				PropertiesConverter.propertiesToString(stepExecution.getStreamContext().getProperties()),
 				stepExecution.getExitStatus().isContinuable() ? "Y" : "N", stepExecution.getExitStatus().getExitCode(),
 				stepExecution.getExitStatus().getExitDescription() };
 		jdbcTemplate.update(getSaveStepExecutionQuery(), parameters, new int[] { Types.INTEGER, Types.INTEGER,
@@ -392,7 +398,7 @@ public class JdbcStepDao implements StepDao, InitializingBean {
 			Integer version = new Integer(stepExecution.getVersion().intValue() + 1);
 			Object[] parameters = new Object[] { stepExecution.getStartTime(), stepExecution.getEndTime(),
 					stepExecution.getStatus().toString(), stepExecution.getCommitCount(), stepExecution.getTaskCount(),
-					PropertiesConverter.propertiesToString(stepExecution.getStatistics()),
+					PropertiesConverter.propertiesToString(stepExecution.getStreamContext().getProperties()),
 					stepExecution.getExitStatus().isContinuable() ? "Y" : "N",
 					stepExecution.getExitStatus().getExitCode(), exitDescription, version, stepExecution.getId(),
 					stepExecution.getVersion() };

spring-batch-execution/src/main/java/org/springframework/batch/execution/step/simple/SimpleStepExecutor.java

@@ -34,6 +34,7 @@ import org.springframework.batch.execution.scope.StepSynchronizationManager;
 import org.springframework.batch.io.Skippable;
 import org.springframework.batch.io.exception.BatchCriticalException;
 import org.springframework.batch.item.StreamContext;
+import org.springframework.batch.item.stream.GenericStreamContext;
 import org.springframework.batch.item.stream.SimpleStreamManager;
 import org.springframework.batch.item.stream.StreamManager;
 import org.springframework.batch.repeat.ExitStatus;
@@ -227,7 +228,8 @@ public class SimpleStepExecutor {
 										// aggregate these contributions if they
 										// come in asynchronously.
 										StreamContext statistics = stepContext.getStreamContext();
-										contribution.setStatistics(statistics.getProperties());
+										contribution.setStreamContext(new GenericStreamContext(statistics
+												.getProperties()));
 										contribution.incrementCommitCount();
 										// Apply the contribution to the step
 										// only if chunk was successful

spring-batch-execution/src/test/java/org/springframework/batch/execution/repository/dao/AbstractStepDaoTests.java

@@ -22,10 +22,10 @@ import java.util.Properties;
 
 import org.springframework.batch.core.domain.BatchStatus;
 import org.springframework.batch.core.domain.Job;
-import org.springframework.batch.core.domain.JobSupport;
 import org.springframework.batch.core.domain.JobExecution;
 import org.springframework.batch.core.domain.JobInstance;
 import org.springframework.batch.core.domain.JobParameters;
+import org.springframework.batch.core.domain.JobSupport;
 import org.springframework.batch.core.domain.StepExecution;
 import org.springframework.batch.core.domain.StepInstance;
 import org.springframework.batch.core.runtime.ExitCodeExceptionClassifier;
@@ -51,15 +51,15 @@ public abstract class AbstractStepDaoTests extends AbstractTransactionalDataSour
 	protected StepDao stepDao;
 
 	protected JobInstance jobInstance;
-	
+
 	protected StepInstance step1;
-	
+
 	protected StepInstance step2;
-	
+
 	protected StepExecution stepExecution;
 
 	protected JobExecution jobExecution;
-	
+
 	protected JobParameters jobParameters = new JobParameters();
 
 	public void setJobDao(JobDao jobDao) {
@@ -88,67 +88,68 @@ public abstract class AbstractStepDaoTests extends AbstractTransactionalDataSour
 		step1 = stepDao.createStep(jobInstance, "TestStep1");
 		step2 = stepDao.createStep(jobInstance, "TestStep2");
 		jobExecution = new JobExecution(step2.getJobInstance());
-		
+
 		stepExecution = new StepExecution(step1, jobExecution, null);
 		stepExecution.setStatus(BatchStatus.STARTED);
 		stepExecution.setStartTime(new Date(System.currentTimeMillis()));
 		stepDao.save(stepExecution);
 	}
-	
+
 	public void testVersionIsNotNullForStep() throws Exception {
-		int version = jdbcTemplate.queryForInt("select version from BATCH_STEP_INSTANCE where ID="+step1.getId());
+		int version = jdbcTemplate.queryForInt("select version from BATCH_STEP_INSTANCE where ID=" + step1.getId());
 		assertEquals(0, version);
 	}
-	
+
 	public void testVersionIsNotNullForStepExecution() throws Exception {
-		int version = jdbcTemplate.queryForInt("select version from BATCH_STEP_EXECUTION where ID="+stepExecution.getId());
+		int version = jdbcTemplate.queryForInt("select version from BATCH_STEP_EXECUTION where ID="
+				+ stepExecution.getId());
 		assertEquals(0, version);
 	}
-	
-	public void testFindStepNull(){
-		
+
+	public void testFindStepNull() {
+
 		StepInstance step = stepDao.findStep(jobInstance, "UnSavedStep");
 		assertNull(step);
 	}
-	
-	public void testFindStep(){
-		
+
+	public void testFindStep() {
+
 		StepInstance tempStep = stepDao.findStep(jobInstance, "TestStep1");
 		assertEquals(tempStep, step1);
 	}
-	
-	public void testFindSteps(){
-		
+
+	public void testFindSteps() {
+
 		List steps = stepDao.findSteps(jobInstance);
 		assertEquals(steps.size(), 2);
 		assertTrue(steps.contains(step1));
 		assertTrue(steps.contains(step2));
 	}
-	
-	public void testFindStepsNotSaved(){
-		
-		//no steps are saved for given id, empty list should be returned
+
+	public void testFindStepsNotSaved() {
+
+		// no steps are saved for given id, empty list should be returned
 		List steps = stepDao.findSteps(new JobInstance(new Long(38922), jobParameters));
 		assertEquals(steps.size(), 0);
 	}
-	
-	public void testCreateStep(){
-		
+
+	public void testCreateStep() {
+
 		StepInstance step3 = stepDao.createStep(jobInstance, "TestStep3");
 		StepInstance tempStep = stepDao.findStep(jobInstance, "TestStep3");
 		assertEquals(step3, tempStep);
 	}
-	
-	public void testUpdateStepWithoutStreamContext(){
-		
+
+	public void testUpdateStepWithoutStreamContext() {
+
 		step1.setStatus(BatchStatus.COMPLETED);
 		stepDao.update(step1);
 		StepInstance tempStep = stepDao.findStep(jobInstance, step1.getName());
 		assertEquals(tempStep, step1);
 	}
-	
-	public void testUpdateStepWithStreamContext(){
-		
+
+	public void testUpdateStepWithStreamContext() {
+
 		step1.setStatus(BatchStatus.COMPLETED);
 		Properties data = new Properties();
 		data.setProperty("restart.key1", "restartData");
@@ -157,87 +158,94 @@ public abstract class AbstractStepDaoTests extends AbstractTransactionalDataSour
 		stepDao.update(step1);
 		StepInstance tempStep = stepDao.findStep(jobInstance, step1.getName());
 		assertEquals(tempStep, step1);
-		assertEquals(tempStep.getStreamContext().getProperties().toString(), 
-				streamContext.getProperties().toString());
+		assertEquals(tempStep.getStreamContext().getProperties().toString(), streamContext.getProperties().toString());
 	}
-	
-	public void testSaveStepExecution(){
-		
+
+	public void testSaveStepExecution() {
+
 		StepExecution execution = new StepExecution(step2, jobExecution, null);
 		execution.setStatus(BatchStatus.STARTED);
 		execution.setStartTime(new Date(System.currentTimeMillis()));
 		Properties statistics = new Properties();
 		statistics.setProperty("statistic.key1", "0");
 		statistics.setProperty("statistic.key2", "5");
-		execution.setStatistics(statistics);
-		execution.setExitStatus(new ExitStatus(false, ExitCodeExceptionClassifier.FATAL_EXCEPTION, "java.lang.Exception"));
+		execution.setStreamContext(new GenericStreamContext(statistics));
+		execution.setExitStatus(new ExitStatus(false, ExitCodeExceptionClassifier.FATAL_EXCEPTION,
+				"java.lang.Exception"));
 		stepDao.save(execution);
 		List executions = stepDao.findStepExecutions(step2);
 		assertEquals(1, executions.size());
-		StepExecution tempExecution = (StepExecution)executions.get(0);
+		StepExecution tempExecution = (StepExecution) executions.get(0);
 		assertEquals(execution, tempExecution);
-		assertEquals(execution.getStatistics(), tempExecution.getStatistics());
+		assertEquals(execution.getStreamContext().getString("statistic.key1"), tempExecution.getStreamContext()
+				.getString("statistic.key1"));
 		assertEquals(execution.getExitStatus(), tempExecution.getExitStatus());
 	}
-	
-	public void testUpdateStepExecution(){
-		
+
+	public void testUpdateStepExecution() {
+
 		stepExecution.setStatus(BatchStatus.COMPLETED);
 		stepExecution.setEndTime(new Date(System.currentTimeMillis()));
 		stepExecution.setCommitCount(5);
 		stepExecution.setTaskCount(5);
-		stepExecution.setStatistics(new Properties());
-		stepExecution.setExitStatus(new ExitStatus(false, ExitCodeExceptionClassifier.FATAL_EXCEPTION, "java.lang.Exception"));
+		stepExecution.setStreamContext(new StreamContext());
+		stepExecution.setExitStatus(new ExitStatus(false, ExitCodeExceptionClassifier.FATAL_EXCEPTION,
+				"java.lang.Exception"));
 		stepDao.update(stepExecution);
 		List executions = stepDao.findStepExecutions(step1);
 		assertEquals(1, executions.size());
-		StepExecution tempExecution = (StepExecution)executions.get(0);
+		StepExecution tempExecution = (StepExecution) executions.get(0);
 		assertEquals(stepExecution, tempExecution);
 		assertEquals(stepExecution.getExitStatus(), tempExecution.getExitStatus());
 	}
-	
-	public void testUpdateStepExecutionWithNullId(){
+
+	public void testUpdateStepExecutionWithNullId() {
 		StepExecution stepExecution = new StepExecution(null, null, null);
-		try{
+		try {
 			stepDao.update(stepExecution);
 			fail("Expected IllegalArgumentException");
-		}catch(IllegalArgumentException ex){
-			//expected
+		}
+		catch (IllegalArgumentException ex) {
+			// expected
 		}
 	}
-	
-	public void testGetStepExecutionCountForNoExecutions(){
-		
+
+	public void testGetStepExecutionCountForNoExecutions() {
+
 		int executionCount = stepDao.getStepExecutionCount(step2);
 		assertEquals(executionCount, 0);
 	}
 
-	public void testIncrementStepExecutionCount(){
-		
+	public void testIncrementStepExecutionCount() {
+
 		assertEquals(1, stepDao.getStepExecutionCount(step1));
-		StepExecution execution = new StepExecution(step1, new JobExecution(step1.getJobInstance(), new Long(123)), null);
+		StepExecution execution = new StepExecution(step1, new JobExecution(step1.getJobInstance(), new Long(123)),
+				null);
 		stepDao.save(execution);
 		assertEquals(2, stepDao.getStepExecutionCount(step1));
 	}
-		
+
 	public void testUpdateStepExecutionVersion() throws Exception {
 		int before = stepExecution.getVersion().intValue();
 		stepDao.update(stepExecution);
 		int after = stepExecution.getVersion().intValue();
-		assertEquals("StepExecution version not updated", before+1, after);
+		assertEquals("StepExecution version not updated", before + 1, after);
 	}
 
 	public void testUpdateStepExecutionOptimisticLocking() throws Exception {
-		stepExecution.incrementVersion(); // not really allowed outside dao code
+		stepExecution.incrementVersion(); // not really allowed outside dao
+											// code
 		try {
 			stepDao.update(stepExecution);
 			fail("Expected OptimisticLockingFailureException");
 		}
 		catch (OptimisticLockingFailureException e) {
 			// expected
-			assertTrue("Exception message should contain step execution id: "+e.getMessage(), e.getMessage().indexOf(""+stepExecution.getId())>=0);
-			assertTrue("Exception message should contain step execution version: "+e.getMessage(), e.getMessage().indexOf(""+stepExecution.getVersion())>=0);
+			assertTrue("Exception message should contain step execution id: " + e.getMessage(), e.getMessage().indexOf(
+					"" + stepExecution.getId()) >= 0);
+			assertTrue("Exception message should contain step execution version: " + e.getMessage(), e.getMessage()
+					.indexOf("" + stepExecution.getVersion()) >= 0);
 		}
 	}
-	
+
 }

spring-batch-execution/src/test/java/org/springframework/batch/execution/step/simple/SimpleStepExecutorTests.java

@@ -409,7 +409,7 @@ public class SimpleStepExecutorTests extends TestCase {
 		JobExecution jobExecution = new JobExecution(jobInstance);
 		StepExecution stepExecution = new StepExecution(step, jobExecution);
 
-		assertEquals(null, stepExecution.getStatistics().getProperty("foo"));
+		assertEquals(null, stepExecution.getStreamContext().getString("foo"));
 
 		final Map map = new HashMap();
 		stepExecutor.setStreamManager(new SimpleStreamManager() {
@@ -423,7 +423,7 @@ public class SimpleStepExecutorTests extends TestCase {
 
 		// At least once in that process the statistics service was asked for
 		// statistics...
-		assertEquals("bar", stepExecution.getStatistics().getProperty("foo"));
+		assertEquals("bar", stepExecution.getStreamContext().getString("foo"));
 		// ...but nothing was registered because nothing with step scoped.
 		assertEquals(0, map.size());
 	}

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

@@ -0,0 +1,59 @@
+/*
+ * 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.item.stream;
+
+import java.util.Properties;
+
+import org.springframework.batch.item.ItemStream;
+import org.springframework.batch.item.StreamContext;
+import org.springframework.batch.item.StreamException;
+
+/**
+ * @author Dave Syer
+ *
+ */
+public class ItemStreamAdapter implements ItemStream {
+
+	/**
+	 * No-op.
+	 * @see org.springframework.batch.item.ItemStream#close()
+	 */
+	public void close() throws StreamException {
+	}
+
+	/**
+	 * No-op.
+	 * @see org.springframework.batch.item.ItemStream#open()
+	 */
+	public void open() throws StreamException {
+	}
+
+	/**
+	 * No-op.
+	 * @see org.springframework.batch.item.ItemStream#restoreFrom(org.springframework.batch.item.StreamContext)
+	 */
+	public void restoreFrom(StreamContext context) {
+	}
+
+	/**
+	 * Return empty {@link StreamContext}.
+	 * @see org.springframework.batch.item.StreamContextProvider#getStreamContext()
+	 */
+	public StreamContext getStreamContext() {
+		return new GenericStreamContext(new Properties());
+	}
+
+}