Package ucar.nc2.iosp

Interface IOServiceProvider

  • All Superinterfaces:
    AutoCloseable, Closeable
    All Known Implementing Classes:
    AbstractIOServiceProvider
    public interface IOServiceProvider
extends Closeable
    This is the service provider interface for the low-level I/O access classes (read only). This is only used by service implementors. An implementation must have a no-argument constructor. The NetcdfFile class manages all registered IOServiceProvider classes. When NetcdfFiles.open() is called:
    1. the file is opened as a ucar.unidata.io.RandomAccessFile;
    2. the file is handed to the isValidFile() method of each registered IOServiceProvider class (until one returns true, which means it can read the file).
    3. the open() method on the resulting IOServiceProvider class is handed the file.

    • Method Detail

      • isValidFile

        boolean isValidFile​(RandomAccessFile raf)
             throws IOException
        Check if this is a valid file for this IOServiceProvider. You must make this method thread safe, ie dont keep any state.
        Parameters:
        raf - RandomAccessFile
        Returns:
        true if valid.
        Throws:
        IOException - if read error

      • build

        void build​(RandomAccessFile raf,
           Group.Builder rootGroup,
           CancelTask cancelTask)
    throws IOException
        Read an existing RandomAccessFile, and populate rootGroup. Note that you cannot reference the NetcdfFile within this routine, since it hasnt been created yet.
        Parameters:
        raf - the file to work on, it has already passed the isValidFile() test.
        rootGroup - add objects to the root group.
        cancelTask - used to monitor user cancellation; may be null.
        Throws:
        IOException - if read error

      • buildFinish

        void buildFinish​(NetcdfFile ncfile)
        Sometimes the builder needs access to the finished objects. This is called when ncfile is finished being built.

      • readArrayData

        Array<?> readArrayData​(Variable v2,
                       Section section)
                throws IOException,
                       InvalidRangeException
        Read data from a top level Variable and return a memory resident Array. This Array has the same element type as the Variable, and the requested shape.
        Parameters:
        v2 - a top-level Variable
        section - the section of data to read. There must be a Range for each Dimension in the variable, in order. Note: no nulls allowed. IOSP may not modify.
        Returns:
        the requested data in a memory-resident Array
        Throws:
        IOException
        InvalidRangeException

      • getSequenceIterator

        Iterator<StructureData> getSequenceIterator​(Sequence s,
                                            int bufferSize)
        Get the structure iterator. Iosps with top level sequences must override.
        Parameters:
        s - the Structure
        bufferSize - the buffersize, may be -1 for default.
        Returns:
        an iterator over the StructureData

      • close

        void close()
    throws IOException
        Close the file. It is the IOServiceProvider's job to close the file (even though it didnt open it), and to free any other resources it has used.
        Specified by:
        close in interface AutoCloseable
        Specified by:
        close in interface Closeable
        Throws:
        IOException - if read error

      • release

        void release()
      throws IOException
        Release any system resources like file handles. Optional, implement only if you are able to reacquire. Used when object is made inactive in cache.
        Throws:
        IOException

      • reacquire

        void reacquire()
        throws IOException
        Reacquire any resources like file handles Used when reactivating in cache.
        Throws:
        IOException

      • getLastModified

        long getLastModified()
        Get last time the file was modified.

      • sendIospMessage

        @Nullable
Object sendIospMessage​(@Nullable
                       Object message)
        A way to communicate arbitrary information to and from an iosp.
        Parameters:
        message - opaque message sent to the IOSP object when its opened (not when isValidFile() is called)
        Returns:
        opaque Object, may be null.

      • toStringDebug

        String toStringDebug​(Object o)
        Debug info for this object.
        Parameters:
        o - which object
        Returns:
        debug info for this object

      • getDetailInfo

        String getDetailInfo()
        Show debug / underlying implementation details
        Returns:
        debug info

      • getFileTypeId

        String getFileTypeId()
        Get a unique id for this file type.
        Returns:
        registered id of the file type
        See Also:
        "https://www.unidata.ucar.edu/software/netcdf-java/formats/FileTypes.html"

      • getFileTypeVersion

        String getFileTypeVersion()
        Get the version of this file type.
        Returns:
        version of the file type
        See Also:
        "https://www.unidata.ucar.edu/software/netcdf-java/formats/FileTypes.html"

      • getFileTypeDescription

        String getFileTypeDescription()
        Get a human-readable description for this file type.
        Returns:
        description of the file type
        See Also:
        "https://www.unidata.ucar.edu/software/netcdf-java/formats/FileTypes.html"