/*
* Copyright 1998, University Corporation for Atmospheric Research
* All Rights Reserved.
* See file LICENSE for copying and redistribution conditions.
*
* $Id: Plain.java,v 1.28 2002-10-21 20:07:44 donm Exp $
*/
package visad.data.netcdf;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.rmi.RemoteException;
import java.util.Set;
import java.util.StringTokenizer;
import java.util.TreeSet;
import ucar.netcdf.Netcdf;
import ucar.netcdf.NetcdfFile;
import ucar.netcdf.Schema;
import ucar.netcdf.Variable;
import ucar.netcdf.VariableIterator;
import visad.data.BadFormException;
import visad.data.FormNode;
import visad.data.netcdf.in.*;
import visad.data.netcdf.out.VisADAdapter;
import visad.Data;
import visad.DataImpl;
import visad.UnimplementedException;
import visad.VisADException;
/**
* A moderately stupid implementation of a netCDF data form for the
* storage of persistent data objects on local disk.
*/
public class
Plain
extends NetCDF
{
/**
* The quantity database to use for mapping netCDF variables to
* VisAD Quantity-s.
*/
private final QuantityDB quantityDB;
/**
* The flag for transforming netCDF char variables to Text
*/
private final boolean charToText;
/**
* Constructs a default, netCDF data form.
*
* @throws VisADException Couldn't create necessary VisAD object
*/
public
Plain()
throws VisADException
{
this(QuantityDBManager.instance(), false);
}
/**
* Constructs a netCDF data form that converts
*
* @param charToText The char to Text flag
*/
public
Plain(boolean charToText)
{
this(QuantityDBManager.instance(), charToText);
}
/**
* Constructs a netCDF data form that uses the given quantity database.
*
* @param db The quantity database.
*/
public
Plain(QuantityDB db)
{
this(db, false);
}
/**
* Constructs a netCDF data form that uses the given quantity database,
* and the flag for converting char to Text.
*
* @param db The quantity database.
* @param charToText The char to Text flag
*/
public
Plain(QuantityDB db, boolean charToText)
{
super("Plain");
quantityDB = db;
this.charToText = charToText;
}
/**
* Save a VisAD data object in this form.
*
* @param path The pathname of the netCDF file to
* be created.
* @param data The data to be saved.
* @param replace Whether to replace an existing file.
* @exception BadFormException netCDF can't handle data object
* @exception VisADException Couldn't create necessary VisAD object
* @exception IOException I/O error. File might already exist.
* @exception RemoteException Remote execution error
* @exception UnimplementedException
* Not yet!
*/
public synchronized void
save(String path, Data data, boolean replace)
throws BadFormException, IOException, RemoteException, VisADException,
UnimplementedException
{
VisADAdapter adapter = new VisADAdapter(data);
Schema schema = new Schema(adapter);
NetcdfFile file = new NetcdfFile(path, replace, /*fill=*/false,
schema);
try
{
VariableIterator iter = file.iterator();
while (iter.hasNext())
{
Variable outVar = iter.next();
Variable inVar = adapter.get(outVar.getName());
int rank = outVar.getRank();
int[] origin = new int[rank];
for (int i = 0; i < rank; ++i)
origin[i] = 0;
outVar.copyin(origin, inVar);
}
}
finally
{
file.close();
}
}
/**
* Add data to an existing data object.
*
* @param id Pathname of the existing netCDF file.
* @param data Data to be saved.
* @param replace Whether or not to replace duplicate, existing data.
* @exception BadFormException
* netCDF can't handle data object.
*/
public synchronized void
add(String id, Data data, boolean replace)
throws BadFormException
{
}
/**
* Returns a VisAD data object corresponding to a netCDF dataset.
*
* @param spec Specification of the existing netCDF dataset.
* @return A VisAD data object corresponding to the netCDF
* dataset.
* @throws BadFormException if the netCDF dataset cannot be adapted to a
* VisAD data object.
* @throws VisADException if a problem occurs in core VisAD. Probably a
* VisAD object couldn't be created.
* @throws IOException if an I/O failure occurs.
* @see NetcdfAdapter#getData()
*/
public synchronized DataImpl
open(String spec)
throws BadFormException, IOException, VisADException
{
return
new NetcdfAdapter(
new NetcdfFile(spec, /*readonly=*/true),
quantityDB,
charToText
).getData();
}
/**
* Returns a VisAD data object corresponding to a netCDF dataset
* and imported according to a given strategy. Among the
* pre-defined import strategies are {@link Strategy#DEFAULT},
* {@link Strategy#MERGED_FILE_FLAT_FIELDS}, {@link
* Strategy#UNMERGED_FILE_FLAT_FIELDS}, and {@link Strategy#IN_MEMORY}.
*
* @param spec Specification of the existing netCDF dataset.
* @param strategy The data-import strategy.
* @return A VisAD data object corresponding to the netCDF
* dataset.
* @throws BadFormException if the netCDF dataset cannot be adapted to a
* VisAD data object.
* @throws VisADException if a problem occurs in core VisAD. Probably a
* VisAD object couldn't be created.
* @throws IOException if an I/O failure occurs.
* @see NetcdfAdapter#getData(Strategy)
*/
public synchronized DataImpl
open(String spec, Strategy strategy)
throws BadFormException, IOException, VisADException
{
return
new NetcdfAdapter(
new NetcdfFile(spec, /*readonly=*/true),
quantityDB,
charToText
).getData(strategy);
}
/**
* Open an existing netCDF file and return a proxy for a VisAD data object.
*
* @param path Pathname of the existing netCDF file.
* @return A VisAD object corresponding to the netCDF dataset.
* @exception BadFormException
* The netCDF variable cannot be adapted to a VisAD API.
* @exception VisADException
* Problem in core VisAD. Probably some VisAD object
* couldn't be created.
* @exception IOException
* Data access I/O failure.
*/
public synchronized DataImpl
openProxy(String path)
throws BadFormException, IOException, VisADException
{
NetcdfFile file = new NetcdfFile(path, /*readonly=*/true);
return new NetcdfAdapter(file, quantityDB, charToText).getProxy();
}
/**
* Returns a VisAD data object corresponding to a URL. If the query
* component of the URL is null, then the returned object will
* contain all the variables in the netCDF dataset. If the query component
* is non-null, then it must comprise a comma-separated list of
* netCDF variable names; the returned VisAD data object will contain only
* those variables in the netCDF dataset that are also named in the list
* (i.e. the intersection is returned). Consequently, if the list is empty,
* then null is returned. For example, this form:
* open(new URL("file://myfile.nc?var_one,var_two"));
* will return a VisAD data object consisting only of the
* netCDF variables var_one and var_two
* assuming they are in the file.
*
* @param url The URL of the netCDF dataset.
* @return A VisAD object corresponding to the netCDF datset
* or null.
* @throws FileNotFoundException
* if the URL specifies a file that doesn't exist.
* @throws IOException if an I/O failure occurs.
* @throws VisADException if a necessary VisAD object couldn't be created.
*/
public synchronized DataImpl
open (URL url)
throws FileNotFoundException, IOException, VisADException
{
/*
* URL.getQuery() isn't used to accomodate JDK 1.2.
*/
String query;
{
String file = url.getFile();
int i = file.indexOf('?');
if (i == -1)
{
query = null;
}
else
{
query =
i == file.length() - 1
? ""
: file.substring(i+1);
}
}
Set names = new TreeSet();
if (query != null)
{
for (StringTokenizer st = new StringTokenizer(query, ",");
st.hasMoreTokens(); )
{
names.add(st.nextToken());
}
}
Netcdf netcdf = new NetcdfFile(url);
return
new NetcdfAdapter(
query == null
? netcdf
: new VariableFilter(netcdf, names),
quantityDB, charToText).getData();
}
/**
* Return the data forms that are compatible with a data object.
*
* @param data The VisAD data object to be examined.
* @return this if data is compatible;
* otherwise, null.
* @exception VisADException Problem with core VisAD.
* @exception IOException Problem with local data access.
* @exception RemoteException Problem with remote data access.
*/
public synchronized FormNode
getForms(Data data)
throws VisADException, RemoteException, IOException
{
FormNode form;
try
{
VisADAdapter adapter = new VisADAdapter(data);
form = this;
}
catch (BadFormException e)
{
form = null;
}
return form;
}
/**
* Test this class.
*
* @param args Runtime arguments. Ignored.
* @exception Exception Something went wrong.
*/
public static void main(String[] args)
throws Exception
{
String inPath;
String outPath = "plain.nc";
if (args.length == 0)
inPath = "test.nc";
else
inPath = args[0];
Plain plain = new Plain(args.length > 1);
System.out.println("Opening netCDF dataset \"" + inPath + "\"");
Data data;
try
{
URL url = new URL(inPath);
data = plain.open(url);
}
catch (MalformedURLException e)
{
data = plain.open(inPath);
}
if (data == null)
{
System.out.println("No data");
}
else
{
// System.out.println("Data:\n" + data);
System.out.println("data.getType().toString():\n" +
data.getType());
System.out.println("Writing netCDF dataset \"" + outPath + "\"");
plain.save(outPath, data, /*replace=*/true);
}
}
}
Ads help maintain this website.