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API Changes from Java-Netcdf version 2.2 to 4.0

 Data Model
  * Object names are Unicode Strings. No Restrictions on characters used.
  * DataType STRING are Unicode. In Netcdf3/4, stored as UTF-8 encoded.
  * DataType CHAR are uninterpreted bytes, default is to consider them ascii.
  * DataType ENUM
  * DataType OPAQUE
  * DataType SEQUENCE

API Extensive API changes. Most, but not completely backwards-compatible.
  * change StringBuffer to StringBuilder or Formatter for efficiency and convenience
  
 Package ucar.ma2
   + Array local iterator: hasNext() nextXXXX() methods.

   + ArraySequence handles Sequence with StructureDataIterator.
   * Old ArraySequence now called ArraySequenceNested

   - ArrayStructure.getArrayXXX removed - use getJavaArrayXXX
   + ArrayStructure.getMemberArray() to extract individual member data as Arrays
   + ArrayStructure.convertScalarDouble, Float

   + Section used instead of List<Range>
   + Section.appendRange() idioms for constructing

   - StructureData.convertScalarDouble() removed, use StructureDS.convertScalarDouble()
   - StructureData.getArrayXXX removed - use getJavaArrayXXX
   - StructureData.findMemberArray removed - use getArray
   + StructureData.convertScalarDouble, Float
   * StructureData.getScalarXXX(String memberName), getJavaArrayXXX(String memberName) must match type exactly

 Package ucar.nc2
   * Attribute mutable methods no longer public, so Attribute is immutable

   - Dimension.getCoordinateVariables(), addCoordinateVariable() removed
   + Dimensions know what Group they belong to
   * Dimension.UNKNOWN now DIMENSION.VLEN
   - Dimension.UNLIMITED removed
   * Dimension can be set immutable.

   + EnumTypedef class added for DataType.ENUM

   + Group tracks EnumTypedef
   + Group.findVariableEscaped() assumes variable name is escaped.
   + Group can be set immutable.

   * IOServiceProvider -> ucar.nc2.iosp.IOServiceProvider

   + NetcdfFile.addStringVariable(), addVariable() convenience methods
   - NetcdfFile.addRecordStructure removed, use sendIospMessage(IOSP_MESSAGE_ADD_RECORD_STRUCTURE)
   - NetcdfFile.readMemberData() removed: use Structure.select() or readSection()
   + NetcdfFile.readToByteChannel experimental, for maximum performance
   - NetcdfFile.read(String variableSection, boolean flatten) -> readSection(secSpec); flatten= false not supported
   + NetcdfFile implements FileCacheable
   * NetcdfFile.setFileCache() replaced old setCacheState().

   + NetcdfFileWriteable has new convenience methods
   + NetcdfFileWriteable redefine mode, large file support, extra header bytes

   - NCdump is deprecated, use NCdumpW which uses a java.io.Writer to do Unicode correctly
   * NCdumpW.CEresult put in sepetat class
   * NCdumpW.makeSectionString moved to CEresult

   * VariableSimpleIF.convertScaleOffsetMissing moved to VariableEnhanced
   * VariableIF extends VariableSimpleIF

   - Variable.getCoordinateDimension() removed
   - Variable.calcIsCoordinateVariable() removed
   + Variable.isCoordinateVariable() added
   - Variable.setIsCoordinateAxis() removed
   - Variable.set/getIOVar() removed
   * Variable can be set immutable.
   - Variable.readAllStructures is removed

   + Sequence is a one-dimensional Structure with indeterminate length

   * Structure.select() create subset consisting only of given member variables
   - Structure.convertXXX removed

   + VariableSimpleAdapter adapts a StructureMembers.Member into a VariableSimpleIF

  Package ucar.nc2.dataset
   * NetcdfDataset.EnhanceMode to control enhancing
   * StructureDS correctly gets enhanced
   * NetcdfDataset.makeArray -> Array.makeArray()
   + both NetcdfFile and NetcdfDataset are in the same FileCache, using acquireXXX().
   + FileCache configuration done though NetcdfDataset.

   - VariableDS.isEnhanced() removed

  Package ucar.nc2.dt
   * TypedDatasetFactory is superceded by ucar.nc2.ft.FeatureDatasetFactoryManager
   * ucar.nc2.dt.RadialDatasetSweep implements ucar.nc2.ft.FeatureDataset
   * ucar.nc2.dt.grid.GridDataset implements ucar.nc2.ft.FeatureDataset

  Package ucar.nc2.iosp
   * Layouts and Chunkers factored out for reuse
     - IndexChunker, IndexChunkerTiled
     - LayoutRegular, LayoutRegularSegmented, LayoutSegmented, LayoutTIled, LayoutBBTiled
   * IOServiceProvider.readNestedData() not needed anymore. optimize readData(Structure struct),
      where struct has only a subset of member Variables
   + IOServiceProvider.readSection(secSpec) with default implementation in AbstractIOServiceProvider
   + IOServiceProvider.readData(ucar.nc2.Variable v2, Section section, WritableByteChannel channel)
     to allow use of nio.Channels

  Package ucar.nc2.iosp.netcdf3
    * netcdf3 format is now just one of the possible IOSPs
    * N3streamWriter allows netcdf3 to be written as a stream

  Package ucar.nc2.util
    * RuntimeConfigParser -> ucar.nc2.util.xml

  Package ucar.nc2.thredds
    * ThreddsDataFactory returns ucar.nc2.ft.FeatureDataset instead of ucar.nc2.dt.TypedDataset
	* ThreddsDataFactory uses Formatter instead of StringBuffer / StringBuilder
	* ThreddsDataFactory.openDatatype renamed to openFeatureDataset

  Package ucar.nc2.util.cache
    * FileCache uses FileCacheable and FileFactory, replaces NetcdfFileCache, NetcdfDatasetCache, HTTPFileCache
    + FileCache no longer static, allows any number of caches. uses java.util.concurrent
    * FileCacheRaf handles RandomAccessFile caching for TDS HTTP file serving.

  Package ucar.nc2.units
    * DateUnit is not a superclass of SimpleUnit

  Package thredds.catalog
    * DataType -> ucar.nc2.constants.FeatureType

  Refactoring to reduce dependencies among modules (core, netcdf, ui, tds)
    * ucar.nc2.dataset.conv._Coordinate moved to ucar.nc2.constants
    * thredds.catalog.DataType moved to ucar.nc2.constants
    * ucar.nc2.dataset.AxisType moved to ucar.nc2.constants

    * thredds.util.DateFromString moved to ucar.nc2.units
    * thredds.datatype to ucar.nc2.units

    * thredds.util to ucar.nc2.util
    * thredds.util.net to ucar.nc2.util.net
    * ucar.nc2.dataset.HttpClientManager to ucar.nc2.util.net
    * remove opendap.dap.DConnect2, ucar.unidata.io.http.HTTPRandomAccessFile from HttpClientManager: must be done seperately
    * ucar.nc2.util.NetworkUtils to ucar.nc2.util.net.URLnaming

    * thredds.util.net.URLExtractor to ui module
    * thredds.util.ListenerManager to ui module
    * thredds.util.Resource to ui module
    * thredds.util.SocketMessage to ui module
    * thredds.datamodel to ui
    * thredds.tools to ui

    * thredds.cataloggen.catalogGenMain (org.apache.log4j) to tds module
    * thredds.dqc to tds
    * thredds.cataloggen.CatalogRefInfo to thredds.cataloggen.config