Package org.springframework.batch.item.xml

Class StaxEventItemReader<T>

java.lang.Object

org.springframework.batch.item.ItemStreamSupport

org.springframework.batch.item.support.AbstractItemStreamItemReader<T>

org.springframework.batch.item.support.AbstractItemCountingItemStreamItemReader<T>

org.springframework.batch.item.xml.StaxEventItemReader<T>

All Implemented Interfaces:

ResourceAwareItemReaderItemStream<T>, ItemReader<T>, ItemStream, ItemStreamReader<T>, org.springframework.beans.factory.InitializingBean

public class StaxEventItemReader<T>
extends AbstractItemCountingItemStreamItemReader<T>
implements ResourceAwareItemReaderItemStream<T>, org.springframework.beans.factory.InitializingBean

Item reader for reading XML input based on StAX.

It extracts fragments from the input XML document which correspond to records for processing. The fragments are wrapped with StartDocument and EndDocument events so that the fragments can be further processed like standalone XML documents.

The implementation is not thread-safe.

Author:

Robert Kasanicky, Mahmoud Ben Hassine, Glenn Renfro

Field Summary

Fields

Modifier and Type	Field	Description
static final String	DEFAULT_ENCODING

Constructor Summary

Constructors

Constructor	Description
StaxEventItemReader()

Method Summary

Modifier and Type	Method	Description
void	afterPropertiesSet()	Ensure that all required dependencies for the ItemReader to run are provided after all properties have been set.
protected void	doClose()	Close the resources opened in AbstractItemCountingItemStreamItemReader.doOpen().
protected void	doOpen()	Open resources necessary to start reading input.
protected T	doRead()	Move to next fragment and map it to item.
protected boolean	isFragmentRootElementName(QName name)
protected void	jumpToItem(int itemIndex)	Move to the given item index.
protected boolean	moveCursorToNextFragment(XMLEventReader reader)	Responsible for moving the cursor before the StartElement of the fragment root.
void	setEncoding(String encoding)	Set encoding to be used for the input file.
void	setFragmentRootElementName(String fragmentRootElementName)
void	setFragmentRootElementNames(String[] fragmentRootElementNames)
void	setResource(org.springframework.core.io.Resource resource)
void	setStrict(boolean strict)	In strict mode the reader will throw an exception on AbstractItemCountingItemStreamItemReader.open(org.springframework.batch.item.ExecutionContext) if the input resource does not exist.
void	setUnmarshaller(org.springframework.oxm.Unmarshaller unmarshaller)
void	setXmlInputFactory(XMLInputFactory xmlInputFactory)	Set the XMLInputFactory.

Methods inherited from class org.springframework.batch.item.support.AbstractItemCountingItemStreamItemReader

close, getCurrentItemCount, isSaveState, open, read, setCurrentItemCount, setMaxItemCount, setSaveState, update

Methods inherited from class org.springframework.batch.item.ItemStreamSupport

getExecutionContextKey, getName, setExecutionContextName, setName

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.springframework.batch.item.ItemReader

read

Methods inherited from interface org.springframework.batch.item.ItemStream

close, open, update

Field Details

DEFAULT_ENCODING

public static final String DEFAULT_ENCODING

Constructor Details

StaxEventItemReader

public StaxEventItemReader()

Method Details

setStrict

public void setStrict(boolean strict)

In strict mode the reader will throw an exception on AbstractItemCountingItemStreamItemReader.open(org.springframework.batch.item.ExecutionContext) if the input resource does not exist.

Parameters:

strict - true by default

setResource

public void setResource(org.springframework.core.io.Resource resource)

Specified by:

setResource in interface ResourceAwareItemReaderItemStream<T>

setUnmarshaller

public void setUnmarshaller(org.springframework.oxm.Unmarshaller unmarshaller)

Parameters:

unmarshaller - maps xml fragments corresponding to records to objects

setFragmentRootElementName

public void setFragmentRootElementName(String fragmentRootElementName)

Parameters:

fragmentRootElementName - name of the root element of the fragment

setFragmentRootElementNames

public void setFragmentRootElementNames(String[] fragmentRootElementNames)

Parameters:

fragmentRootElementNames - list of the names of the root element of the fragment

setXmlInputFactory

public void setXmlInputFactory(XMLInputFactory xmlInputFactory)

Set the XMLInputFactory.

Parameters:

xmlInputFactory - to use

setEncoding

public void setEncoding(@Nullable
 String encoding)

Set encoding to be used for the input file. Defaults to DEFAULT_ENCODING.

Parameters:

encoding - the encoding to be used. Can be null, in which case, the XML event reader will attempt to auto-detect the encoding from tht input file.

afterPropertiesSet

public void afterPropertiesSet()
                        throws Exception

Ensure that all required dependencies for the ItemReader to run are provided after all properties have been set.

Specified by:

afterPropertiesSet in interface org.springframework.beans.factory.InitializingBean

Throws:

IllegalArgumentException - if the Resource, FragmentDeserializer or FragmentRootElementName is null, or if the root element is empty.

IllegalStateException - if the Resource does not exist.

Exception

See Also:

• InitializingBean.afterPropertiesSet()

moveCursorToNextFragment

protected boolean moveCursorToNextFragment(XMLEventReader reader)
                                    throws NonTransientResourceException

Responsible for moving the cursor before the StartElement of the fragment root.

This implementation simply looks for the next corresponding element, it does not care about element nesting. You will need to override this method to correctly handle composite fragments.

Parameters:

reader - the XMLEventReader to be used to find next fragment.

Returns:

true if next fragment was found, false otherwise.

Throws:

NonTransientResourceException - if the cursor could not be moved. This will be treated as fatal and subsequent calls to read will return null.

doClose

protected void doClose()
                throws Exception

Description copied from class: AbstractItemCountingItemStreamItemReader

Close the resources opened in AbstractItemCountingItemStreamItemReader.doOpen().

Specified by:

doClose in class AbstractItemCountingItemStreamItemReader<T>

Throws:

Exception - Allows subclasses to throw checked exceptions for interpretation by the framework

doOpen

protected void doOpen()
               throws Exception

Description copied from class: AbstractItemCountingItemStreamItemReader

Open resources necessary to start reading input.

Specified by:

doOpen in class AbstractItemCountingItemStreamItemReader<T>

Throws:

Exception - Allows subclasses to throw checked exceptions for interpretation by the framework

doRead

@Nullable
protected T doRead()
            throws IOException,
XMLStreamException

Move to next fragment and map it to item.

Specified by:

doRead in class AbstractItemCountingItemStreamItemReader<T>

Returns:

an item or null if the data source is exhausted

Throws:

IOException

XMLStreamException

jumpToItem

protected void jumpToItem(int itemIndex)
                   throws Exception

Description copied from class: AbstractItemCountingItemStreamItemReader

Move to the given item index. Subclasses should override this method if there is a more efficient way of moving to given index than re-reading the input using AbstractItemCountingItemStreamItemReader.doRead().

Overrides:

jumpToItem in class AbstractItemCountingItemStreamItemReader<T>

Parameters:

itemIndex - index of item (0 based) to jump to.

Throws:

Exception - Allows subclasses to throw checked exceptions for interpretation by the framework

isFragmentRootElementName

protected boolean isFragmentRootElementName(QName name)