Interface FeatureWriter<T extends FeatureType,​F extends Feature>

    • Method Summary

      All Methods Instance Methods Abstract Methods 
      Modifier and Type Method Description
      void close()
      Release the underlying resources.
      T getFeatureType()
      FeatureType this reader has been configured to create.
      boolean hasNext()
      Query whether this FeatureWriter has another Feature.
      F next()
      Reads a Feature from the underlying AttributeReader.
      void remove()
      Removes current Feature, must be called before hasNext.
      void write()
      Writes the current Feature, must be called before hasNext.
    • Method Detail

      • getFeatureType

        T getFeatureType()
        FeatureType this reader has been configured to create.
        Returns:
        FeatureType this writer has been configured to create.
      • next

        F next()
        throws IOException
        Reads a Feature from the underlying AttributeReader.

        This method may return a Feature even though hasNext() returns false, this allows FeatureWriters to provide an ability to append content.

        Returns:
        Feature from Query, or newly appended Feature
        Throws:
        IOException - if the writer has been closed or an I/O error occurs reading the next Feature.
      • remove

        void remove()
             throws IOException
        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).

        Throws:
        IOException
      • write

        void write()
            throws IOException
        Writes the current Feature, must be called before hasNext.

        FeautreWriters will need to allow FeatureSources of the same typeName to issue a FeatureEvent:

        • FeatureEvent.FEATURES_ADDED: when next() has been called with hasNext() equal to false.
        • FeatureEvent.FEATURES_MODIFIED: when next has been called with hasNext() equal to true and the resulting Feature has indeed been modified.

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

        If you have not called write() when you call hasNext() or next(), no modification will occur().

        Throws:
        IOException
      • hasNext

        boolean hasNext()
                 throws IOException
        Query whether this FeatureWriter has another Feature.

        Please note: it is more efficient to construct your FeatureWriter with a Filer (to skip entries you do not want), than to force the creation of entire Features only to skip over them.

        FeatureWriters that support append operations will allow calls to next, even when hasNext() returns false.

        Returns:
        true if an additional Feature is available, false if not.
        Throws:
        IOException - if an I/O error occurs.
      • close

        void close()
            throws IOException
        Release the underlying resources.
        Specified by:
        close in interface AutoCloseable
        Specified by:
        close in interface Closeable
        Throws:
        IOException - if there there are problems releasing underlying resources, or possibly if close has been called (up to the implementation).
        IOException - if an I/O error occurs