org.geotools.data
Class DiffFeatureWriter

Object
  extended by DiffFeatureWriter
All Implemented Interfaces:
FeatureWriter<SimpleFeatureType,SimpleFeature>

public abstract class DiffFeatureWriter
extends Object
implements FeatureWriter<SimpleFeatureType,SimpleFeature>

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
Module:
modules/library/main (gt-main.jar)

Field Summary
protected  Diff diff
           
protected  FeatureReader<SimpleFeatureType,SimpleFeature> reader
           
 
Constructor Summary
DiffFeatureWriter(FeatureReader<SimpleFeatureType,SimpleFeature> reader, Diff diff)
          DiffFeatureWriter construction.
DiffFeatureWriter(FeatureReader<SimpleFeatureType,SimpleFeature> reader, Diff diff, Filter filter)
          DiffFeatureWriter construction.
 
Method Summary
 void close()
          Clean up resources associated with this writer.
protected abstract  void fireNotification(int eventType, ReferencedEnvelope bounds)
          Subclass must provide the notification.
 SimpleFeatureType getFeatureType()
          Supplys FeatureTypeFrom reader
 boolean hasNext()
          Query for more content.
 SimpleFeature 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 Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

reader

protected FeatureReader<SimpleFeatureType,SimpleFeature> reader

diff

protected Diff diff
Constructor Detail

DiffFeatureWriter

public DiffFeatureWriter(FeatureReader<SimpleFeatureType,SimpleFeature> reader,
                         Diff diff)
DiffFeatureWriter construction.

Parameters:
reader -
diff -

DiffFeatureWriter

public DiffFeatureWriter(FeatureReader<SimpleFeatureType,SimpleFeature> reader,
                         Diff diff,
                         Filter filter)
DiffFeatureWriter construction.

Parameters:
reader -
diff -
filter -
Method Detail

getFeatureType

public SimpleFeatureType getFeatureType()
Supplys FeatureTypeFrom reader

Specified by:
getFeatureType in interface FeatureWriter<SimpleFeatureType,SimpleFeature>
Returns:
FeatureType this writer has been configured to create.
See Also:
FeatureWriter.getFeatureType()

next

public SimpleFeature next()
                   throws IOException
Next Feature from reader or new content.

Specified by:
next in interface FeatureWriter<SimpleFeatureType,SimpleFeature>
Returns:
Feature from Query, or newly appended Feature
Throws:
IOException - DOCUMENT ME!
See Also:
FeatureWriter.next()

remove

public void remove()
            throws 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<SimpleFeatureType,SimpleFeature>
Throws:
IOException - DOCUMENT ME!
See Also:
FeatureWriter.remove()

write

public void write()
           throws IOException
Writes out the current feature.

Specified by:
write in interface FeatureWriter<SimpleFeatureType,SimpleFeature>
Throws:
IOException
See Also:
FeatureWriter.write()

hasNext

public boolean hasNext()
                throws IOException
Query for more content.

Specified by:
hasNext in interface FeatureWriter<SimpleFeatureType,SimpleFeature>
Returns:
true if an additional Feature is available.
Throws:
IOException - DOCUMENT ME!
See Also:
FeatureWriter.hasNext()

close

public void close()
           throws 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<SimpleFeatureType,SimpleFeature>
Throws:
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,
                                         ReferencedEnvelope 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 -


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