IOServiceProvider (NetCDF-Java CDM API v5.0.0)

All Known Subinterfaces:

IOServiceProviderWriter

All Known Implementing Classes:

AbstractIOServiceProvider
```
public interface IOServiceProvider
```
This is the service provider interface for the low-level I/O access classes (read only). This is only used by service implementors. The NetcdfFile class manages all registered IOServiceProvider classes. When NetcdfFile.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.
See Also:

;

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method and Description
`void`	`close()` Close the file.
`String`	`getDetailInfo()` Show debug / underlying implementation details
`String`	`getFileTypeDescription()` Get a human-readable description for this file type.
`String`	`getFileTypeId()` Get a unique id for this file type.
`String`	`getFileTypeVersion()` Get the version of this file type.
`StructureDataIterator`	`getStructureIterator(Structure s, int bufferSize)` Get the structure iterator.
`boolean`	`isValidFile(RandomAccessFile raf)` Check if this is a valid file for this IOServiceProvider.
`void`	`open(RandomAccessFile raf, NetcdfFile ncfile, CancelTask cancelTask)` Open existing file, and populate ncfile with it.
`void`	`reacquire()` Reacquire any resources like file handles Used when reactivating in cache.
`Array`	`readData(Variable v2, Section section)` Read data from a top level Variable and return a memory resident Array.
`Array`	`readSection(ParsedSectionSpec cer)` Allows reading sections of nested variables
`long`	`readToByteChannel(Variable v2, Section section, WritableByteChannel channel)` Read data from a top level Variable and send data to a WritableByteChannel.
`long`	`readToOutputStream(Variable v2, Section section, OutputStream out)`
`void`	`release()` Release any system resources like file handles.
`Object`	`sendIospMessage(Object message)` A way to communicate arbitrary information to an iosp.
`long`	`streamToByteChannel(Variable v2, Section section, WritableByteChannel channel)`
`boolean`	`syncExtend()` Extend the NetcdfFile if the underlying dataset has changed in a way that is compatible with the current metadata.
`String`	`toStringDebug(Object o)` Debug info for this object.

- 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
  - open
```
void open(RandomAccessFile raf,
          NetcdfFile ncfile,
          CancelTask cancelTask)
   throws IOException
```
    Open existing file, and populate ncfile with it. This method is only called by the NetcdfFile constructor on itself. The provided NetcdfFile object will be empty except for the location String and the IOServiceProvider associated with this NetcdfFile object.
    
    Parameters:
    
    raf - the file to work on, it has already passed the isValidFile() test.
    
    ncfile - add objects to this empty NetcdfFile
    
    cancelTask - used to monitor user cancellation; may be null.
    
    Throws:
    
    IOException - if read error
  - readData
```
Array readData(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 - if read error
    
    InvalidRangeException - if invalid section
    
    See Also:
    
    Range
  - readToByteChannel
```
long readToByteChannel(Variable v2,
                       Section section,
                       WritableByteChannel channel)
                throws IOException,
                       InvalidRangeException
```
    Read data from a top level Variable and send data to a WritableByteChannel. Must be in big-endian order.
    
    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.
    
    channel - write data to this WritableByteChannel
    
    Returns:
    
    the number of bytes written to the channel
    
    Throws:
    
    IOException - if read error
    
    InvalidRangeException - if invalid section
  - streamToByteChannel
```
long streamToByteChannel(Variable v2,
                         Section section,
                         WritableByteChannel channel)
                  throws IOException,
                         InvalidRangeException
```
    Throws:
    
    IOException
    
    InvalidRangeException
  - readToOutputStream
```
long readToOutputStream(Variable v2,
                        Section section,
                        OutputStream out)
                 throws IOException,
                        InvalidRangeException
```
    Throws:
    
    IOException
    
    InvalidRangeException
  - readSection
```
Array readSection(ParsedSectionSpec cer)
           throws IOException,
                  InvalidRangeException
```
    Allows reading sections of nested variables
    
    Parameters:
    
    cer - section specification : what data is wanted
    
    Returns:
    
    requested data array
    
    Throws:
    
    IOException - on read error
    
    InvalidRangeException - if section spec is invalid
  - getStructureIterator
```
StructureDataIterator getStructureIterator(Structure s,
                                           int bufferSize)
                                    throws IOException
```
    Get the structure iterator. iosps with top level sequences must override. Not threadsafe; do not use multiple StructureDataIterator for the same iosp.
    
    Parameters:
    
    s - the Structure
    
    bufferSize - the buffersize
    
    Returns:
    
    the data iterator
    
    Throws:
    
    IOException - if problem reading data
  - 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.
    
    Throws:
    
    IOException - if read error
  - syncExtend
```
boolean syncExtend()
            throws IOException
```
    Extend the NetcdfFile if the underlying dataset has changed in a way that is compatible with the current metadata. For example, if the unlimited dimension has grown.
    
    Returns:
    
    true if the NetcdfFile was extended.
    
    Throws:
    
    IOException - if a read error occured when accessing the underlying dataset.
  - 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
  - sendIospMessage
```
Object sendIospMessage(Object message)
```
    A way to communicate arbitrary information to an iosp.
    
    Parameters:
    
    message - opaque message sent to the IOSP object when its opened (not when isValidFile() is called)
    
    Returns:
    
    opaque return, 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:
    
    "http://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:
    
    "http://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:
    
    "http://www.unidata.ucar.edu/software/netcdf-java/formats/FileTypes.html"

Interface IOServiceProvider

Method Summary

Method Detail

isValidFile

open

readData

readToByteChannel

streamToByteChannel

readToOutputStream

readSection

getStructureIterator

close

syncExtend

release

reacquire

sendIospMessage

toStringDebug

getDetailInfo

getFileTypeId

getFileTypeVersion

getFileTypeDescription