/*
* Copyright 1998-2014 University Corporation for Atmospheric Research/Unidata
*
* Portions of this software were developed by the Unidata Program at the
* University Corporation for Atmospheric Research.
*
* Access and use of this software shall impose the following obligations
* and understandings on the user. The user is granted the right, without
* any fee or cost, to use, copy, modify, alter, enhance and distribute
* this software, and any derivative works thereof, and its supporting
* documentation for any purpose whatsoever, provided that this entire
* notice appears in all copies of the software, derivative works and
* supporting documentation. Further, UCAR requests that the user credit
* UCAR/Unidata in any publications that result from the use of this
* software or in any product that includes this software. The names UCAR
* and/or Unidata, however, may not be used in any advertising or publicity
* to endorse or promote any products or commercial entity unless specific
* written permission is obtained from UCAR/Unidata. The user also
* understands that UCAR/Unidata is not obligated to provide the user with
* any support, consulting, training or assistance of any kind with regard
* to the use, operation and performance of this software nor to provide
* the user with any updates, revisions, new versions or "bug fixes."
*
* THIS SOFTWARE IS PROVIDED BY UCAR/UNIDATA "AS IS" AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL UCAR/UNIDATA BE LIABLE FOR ANY SPECIAL,
* INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
* FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
* NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
* WITH THE ACCESS, USE OR PERFORMANCE OF THIS SOFTWARE.
*/
package thredds.util.filesource;
import java.io.File;
import java.util.List;
/**
* Implements the FileSource interface using a chain of DescendantFileSource
* objects. This allows a relative path to be given and located in the first
* DescendantFileSource that contains a matching File.
*
* @author edavis
* @since 4.0
*/
public class ChainedFileSource implements FileSource {
//private static org.slf4j.Logger log = org.slf4j.LoggerFactory.getLogger( ChainedFileSource.class );
private final List<DescendantFileSource> chain;
public ChainedFileSource(List<DescendantFileSource> chain) {
if (chain == null || chain.isEmpty())
throw new IllegalArgumentException("Locator chain must not be null or empty.");
for (DescendantFileSource dfs : chain)
if (dfs == null)
throw new IllegalArgumentException("Locator chain must not contain null items.");
this.chain = chain;
}
/**
* This implementation requires a relative path. The relative path may
* not start with "../" or once "normalized" start with "../". Here
* "normalized" means that "./" and "path/.." segments are removed,
* e.g., "dir1/../../dir2" once normalized would be "../dir2".
*
* @param path the relative path to the desired File.
* @return the File represented by the given relative path or null if the path is null or the File it represents does not exist.
*/
public File getFile(String path) {
File file;
for (DescendantFileSource curLocator : chain) {
file = curLocator.getFile(path);
if (file != null)
return file;
}
return null;
}
}