IOServiceProvider (NetCDF-Java CDM Public API v5.4.2)

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. 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 Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method and Description
`void`	`build(RandomAccessFile raf, Group.Builder rootGroup, CancelTask cancelTask)` Open existing file, and populate it.
`void`	`buildFinish(NetcdfFile ncfile)` Sometimes the builder needs access to the finished objects.
`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`	`isBuilder()` If this iosp implements build().
`boolean`	`isValidFile(RandomAccessFile raf)` Check if this is a valid file for this IOServiceProvider.
`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`	`readToOutputStream(Variable v2, Section section, OutputStream out)` Read data from a top level Variable and send data to a OutputStream.
`void`	`release()` Release any system resources like file handles.
`Object`	`sendIospMessage(Object message)` A way to communicate arbitrary information to and from an iosp.
`String`	`toStringDebug(Object o)` Debug info for this object.

- Method Detail
  - build
```
void build(RandomAccessFile raf,
           Group.Builder rootGroup,
           CancelTask cancelTask)
    throws IOException
```
    Open existing file, and populate it. Note that you cannot reference the NetcdfFile within this routine. This is the bridge to immutable objects that will be used exclusively in version 6.
    
    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 after ncfile.build()
  - 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
  - getDetailInfo
```
String getDetailInfo()
```
    Show debug / underlying implementation details
    
    Returns:
    
    debug info
  - 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"
  - 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"
  - 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
  - isBuilder
```
boolean isBuilder()
```
    If this iosp implements build().
  - 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
  - reacquire
```
void reacquire()
        throws IOException
```
    Reacquire any resources like file handles Used when reactivating in cache.
    
    Throws:
    
    IOException
  - 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
  - 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
  - readToOutputStream
```
long readToOutputStream(Variable v2,
                        Section section,
                        OutputStream out)
                 throws IOException,
                        InvalidRangeException
```
    Read data from a top level Variable and send data to a OutputStream. Must be in big-endian order, following ncstream conventions. Default implementation just reads to memory and writes to stream. Allow override for possible performance improvements.
    
    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.
    
    out - write data to this OutputStream
    
    Returns:
    
    the number of bytes written to the channel
    
    Throws:
    
    IOException - if read error
    
    InvalidRangeException - if invalid section
  - 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
  - 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

Interface IOServiceProvider

Method Summary

Method Detail

build

buildFinish

close

getDetailInfo

getFileTypeDescription

getFileTypeId

getFileTypeVersion

getStructureIterator

isBuilder

isValidFile

reacquire

readData

readSection

readToOutputStream

release

sendIospMessage

toStringDebug