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// $Id: CrawlableDatasetFactory.java 63 2006-07-12 21:50:51Z edavis $
package thredds.crawlabledataset;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.io.IOException;
/**
* A description
*
* @author edavis
* @since Jun 23, 2005T10:29:26 PM
*/
public class CrawlableDatasetFactory
{
private static String defaultClassName = "thredds.crawlabledataset.CrawlableDatasetFile";
/**
* Construct a CrawlableDataset for the given path using the
* CrawlableDataset implementation indicated by the given class name.
*
* The class given by className is used to instantiate the requested
* CrawlableDataset and so must be an implementation of
* thredds.crawlabledataset.CrawlableDataset. The given class must also
* supply a public constructor with a single String argument. The String
* argument is the path for the CrawlableDataset being constructed.
*
* If className is null, thredds.crawlabledataset.CrawlableDatasetFile will
* be used.
*
* If the path is an alias containing wildcard characters ("*"),
* the class thredds.crawlabledataset.CrawlableDatasetAlias will be used to
* expand the alias into a collection of CrawlableDatasets of the type given
* by className.
*
* @param path the path of the CrawlableDataset.
* @param className the class name of the CrawlableDataset implementation to instantiate.
* @param configObj
*
* @return a CrawlableDataset for the given path and of the type given by the class name.
*
* @throws IOException if a CrawlableDataset cannot be created due to IO problems.
* @throws ClassNotFoundException if the given CrawlableDataset implementation was not found.
* @throws NoSuchMethodException if the given CrawlableDataset implementation does not have a constructor with a single String parameter which is required.
* @throws IllegalAccessException if the constructor is inaccessible due to Java language access control.
* @throws InvocationTargetException if the constructor throws an exception.
* @throws InstantiationException if the given CrawlableDataset implementation is an abstract class.
*
* @throws NullPointerException if the given path is null.
* @throws IllegalArgumentException if the given class name is not an implementation of CrawlableDataset.
*/
public static CrawlableDataset createCrawlableDataset( String path, String className, Object configObj )
throws IOException,
ClassNotFoundException, NoSuchMethodException,
IllegalAccessException, InvocationTargetException,
InstantiationException, IllegalArgumentException, NullPointerException
// throws CrDsException, IllegalArgumentException
{
if ( path == null ) throw new NullPointerException( "Given path must not be null.");
String tmpClassName = ( className == null
? defaultClassName
: className );
// @todo Remove alias until sure how to handle things like ".scour*" being a regular file.
// if ( CrawlableDatasetAlias.isAlias( tmpPath) )
// return new CrawlableDatasetAlias( tmpPath, tmpClassName, configObj );
// Get the Class instance for desired CrawlableDataset implementation.
Class crDsClass = Class.forName( tmpClassName );
// Check that the Class is a CrawlableDataset.
if ( ! CrawlableDataset.class.isAssignableFrom( crDsClass ) )
{
throw new IllegalArgumentException( "Requested class <" + className + "> not an implementation of thredds.crawlabledataset.CrawlableDataset.");
}
// Instantiate the desired CrawlableDataset.
Class [] argTypes = { String.class, Object.class };
Object [] args = { path, configObj };
Constructor constructor = crDsClass.getDeclaredConstructor( argTypes );
try
{
return (CrawlableDataset) constructor.newInstance( args );
}
catch ( InvocationTargetException e )
{
if ( IOException.class.isAssignableFrom( e.getCause().getClass()) )
throw (IOException) e.getCause();
else throw e;
}
}
/**
* Normalize the given path so that it can be used in the creation of a CrawlableDataset.
* This method can be used on absolute or relative paths.
*
* Normal uses slashes ("/") as path seperator, not backslashes ("\"), and does
* not use trailing slashes. This function allows users to specify Windows
* pathnames and UNC pathnames in there normal manner.
*
* @param path the path to be normalized.
* @return the normalized path.
* @throws NullPointerException if path is null.
*/
public static String normalizePath( String path )
{
// Replace any occurance of a backslash ("\") with a slash ("/").
// NOTE: Both String and Pattern escape backslash, so need four backslashes to find one.
// NOTE: No longer replace multiple backslashes with one slash, which allows for UNC pathnames (Windows LAN addresses).
// Was path.replaceAll( "\\\\+", "/");
String newPath = path.replaceAll( "\\\\", "/");
// Remove trailing slashes.
while ( newPath.endsWith( "/") && ! newPath.equals("/") )
newPath = newPath.substring( 0, newPath.length() - 1 );
return newPath;
}
}