/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2011, Open Source Geospatial Foundation (OSGeo)
* (C) 2005 Open Geospatial Consortium Inc.
*
* All Rights Reserved. http://www.opengis.org/legal/
*/
package org.opengis.coverage.grid;
import java.io.IOException;
import java.io.FileNotFoundException;
import org.opengis.parameter.GeneralParameterValue;
import org.opengis.parameter.ParameterNotFoundException;
import org.opengis.parameter.InvalidParameterNameException;
import org.opengis.parameter.InvalidParameterValueException;
/**
* Support for reading grid coverages out of a persisten store. Instance of
* {@code GridCoverageReader} are obtained through a call to
* {@link GridCoverageExchange#getReader}. Grid coverages are usually
* read from the input stream in a sequential order.
*
*
* @author Martin Desruisseaux (IRD)
* @since GeoAPI 2.0
*
* @see GridCoverageExchange#getReader
* @see javax.imageio.ImageReader
*
*
* @source $URL: http://svn.osgeo.org/geotools/trunk/modules/library/opengis/src/main/java/org/opengis/coverage/grid/GridCoverageReader.java $
*/
public interface GridCoverageReader {
/**
* Returns the format handled by this {@code GridCoverageReader}.
*/
Format getFormat();
/**
* Returns the input source. This is the object passed to the
* {@link GridCoverageExchange#getReader} method. It can be a
* {@link java.lang.String}, an {@link java.io.InputStream}, a
* {@link java.nio.channels.FileChannel}, whatever.
*/
Object getSource();
/**
* Returns the list of metadata keywords associated with the {@linkplain #getSource
* input source} as a whole (not associated with any particular grid coverage).
* If no metadata is available, the array will be empty.
*
* @return The list of metadata keywords for the input source.
* @throws IOException if an error occurs during reading.
*
* @todo This javadoc may not apply thats well in the iterator scheme.
*/
String[] getMetadataNames() throws IOException;
/**
* Retrieve the metadata value for a given metadata name.
*
* @param name Metadata keyword for which to retrieve metadata.
* @return The metadata value for the given metadata name. Should be one of
* the name returned by {@link #getMetadataNames}.
* @throws IOException if an error occurs during reading.
*
* @todo This javadoc may not apply thats well in the iterator scheme.
*/
String getMetadataValue(String name) throws IOException;
/**
* Retrieve the list of grid coverages contained within the {@linkplain #getSource
* input source}. Each grid can have a different coordinate system, number of dimensions
* and grid geometry. For example, a HDF-EOS file (GRID.HDF) contains 6 grid coverages
* each having a different projection. An empty array will be returned if no sub names
* exist.
*
* @return The list of grid coverages contained within the input source.
* @throws IOException if an error occurs during reading.
*
* @todo The javadoc should also be more explicit about hierarchical format.
* Should the names be returned as paths?
* Explain what to return if the GridCoverage are accessible by index
* only. A proposal is to name them "grid1", "grid2", etc.
*/
String[] listSubNames() throws IOException;
/**
* Returns the name for the next grid coverage to be {@linkplain #read read} from the
* {@linkplain #getSource input source}.
*
* @throws IOException if an error occurs during reading.
* @todo Do we need a special method for that, or should it be a metadata?
*/
String getCurrentSubname() throws IOException;
/**
* Returns {@code true} if there is at least one more grid coverage
* available on the stream.
*/
boolean hasMoreGridCoverages() throws IOException;
/**
* Read the grid coverage from the current stream position, and move to the next grid
* coverage. The method {@link #hasMoreGridCoverages} should be invoked first in order
* to verify that a coverage is available.
*
* @param parameters An optional set of parameters. Should be any or all of the
* parameters returned by {@link Format#getReadParameters}.
* @return A new {@linkplain GridCoverage grid coverage} from the input source.
* @throws InvalidParameterNameException if a parameter in {@code parameters}
* doesn't have a recognized name.
* @throws InvalidParameterValueException if a parameter in {@code parameters}
* doesn't have a valid value.
* @throws ParameterNotFoundException if a parameter was required for the operation but was
* not provided in the {@code parameters} list.
* @throws CannotCreateGridCoverageException if the coverage can't be created for a logical
* reason (for example an unsupported format, or an inconsistency found in the data).
* @throws IOException if a read operation failed for some other input/output reason, including
* {@link FileNotFoundException} if no file with the given {@code name} can be
* found, or {@link javax.imageio.IIOException} if an error was thrown by the
* underlying image library.
*/
GridCoverage read(GeneralParameterValue[] parameters)
throws IllegalArgumentException, IOException;
/**
* Skip the current grid coverage without reading it, and move the stream position to
* the next grid coverage.
*
* @throws IOException if the operation failed.
*/
void skip() throws IOException;
/**
* Allows any resources held by this object to be released. The result of calling any other
* method subsequent to a call to this method is undefined. It is important for applications
* to call this method when they know they will no longer be using this {@code GridCoverageReader}.
* Otherwise, the reader may continue to hold on to resources indefinitely.
*
* @throws IOException if an error occured while disposing resources (for example while closing
* a file).
*/
void dispose() throws IOException;
}