org.geotools.data
Class DiffFeatureWriter

java.lang.Object
  org.geotools.data.DiffFeatureWriter

All Implemented Interfaces:

FeatureWriter

public abstract class DiffFeatureWriter

extends java.lang.Object

implements FeatureWriter

A FeatureWriter that captures modifications against a FeatureReader.

You will eventually need to write out the differences, later.

The api has been implemented in terms of FeatureReader to make explicit that no Features are writen out by this Class.

Author:

Jody Garnett, Refractions Research

See Also:

TransactionStateDiff

Field Summary

protected java.util.Map	diff
protected FeatureReader	reader

Constructor Summary

DiffFeatureWriter(FeatureReader reader, java.util.Map diff)
DiffFeatureWriter construction.

DiffFeatureWriter(FeatureReader reader, java.util.Map diff, Filter filter)
DiffFeatureWriter construction.

Method Summary

void	close() Clean up resources associated with this writer.
protected abstract void	fireNotification(int eventType, com.vividsolutions.jts.geom.Envelope bounds) Subclass must provide the notification.
FeatureType	getFeatureType() Supplys FeatureTypeFrom reader
boolean	hasNext() Query for more content.
Feature	next() Next Feature from reader or new content.
void	remove() Removes current Feature, must be called before hasNext.
void	write() Writes out the current feature.

Methods inherited from class java.lang.Object

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

Field Detail

reader

protected FeatureReader reader

diff

protected java.util.Map diff

Constructor Detail

DiffFeatureWriter

public DiffFeatureWriter(FeatureReader reader,
                         java.util.Map diff)

DiffFeatureWriter construction.

Parameters:

reader -

diff -

DiffFeatureWriter

public DiffFeatureWriter(FeatureReader reader,
                         java.util.Map diff,
                         Filter filter)

DiffFeatureWriter construction.

Parameters:

reader -

diff -

Method Detail

getFeatureType

public FeatureType getFeatureType()

Supplys FeatureTypeFrom reader

Specified by:

getFeatureType in interface FeatureWriter

Returns:

FeatureType this writer has been configured to create.

See Also:

FeatureWriter.getFeatureType()

next

public Feature next()
             throws java.io.IOException

Next Feature from reader or new content.

Specified by:

next in interface FeatureWriter

Returns:

Feature from Query, or newly appended Feature

Throws:

java.io.IOException - DOCUMENT ME!

See Also:

FeatureWriter.next()

remove

public void remove()
            throws java.io.IOException

Description copied from interface: FeatureWriter

Removes current Feature, must be called before hasNext.

FeatureWriters will need to allow all FeatureSources of the same typeName to issue a FeatureEvent event of type FeatureEvent.FEATURES_REMOVED when this method is called.

If this FeatureWriter is opperating against a Transaction FEATURES_REMOVED events should only be sent to FeatureSources operating on the same Transaction. When Transaction commit() is called other FeatureSources will be informed of the modifications.

When the current Feature has been provided as new content, this method "cancels" the add opperation (and notification needed).

Specified by:

remove in interface FeatureWriter

Throws:

java.io.IOException - DOCUMENT ME!

See Also:

FeatureWriter.remove()

write

public void write()
           throws java.io.IOException

Writes out the current feature.

Specified by:

write in interface FeatureWriter

Throws:

java.io.IOException

See Also:

FeatureWriter.write()

hasNext

public boolean hasNext()
                throws java.io.IOException

Query for more content.

Specified by:

hasNext in interface FeatureWriter

Returns:

true if an additional Feature is available.

Throws:

java.io.IOException - DOCUMENT ME!

See Also:

FeatureWriter.hasNext()

close

public void close()
           throws java.io.IOException

Clean up resources associated with this writer.

Diff is not clear()ed as it is assumed that it belongs to a Transaction.State object and may yet be written out.

Specified by:

close in interface FeatureWriter

Throws:

java.io.IOException - if there there are problems releasing underlying resources, or possibly if close has been called (up to the implementation).

See Also:

FeatureWriter.close()

fireNotification

protected abstract void fireNotification(int eventType,
                                         com.vividsolutions.jts.geom.Envelope bounds)

Subclass must provide the notification.

Notification requirements for modifications against a Transaction should only be issued to FeatureSource instances that opperate against the same typeName and Transaction.

Other FeatureSource instances with the same typeName will be notified when the Transaction is committed.

Parameters:

eventType - One of FeatureType.FEATURES_ADDED, FeatureType.CHANGED, FeatureType.FEATURES_REMOVED

bounds -