/**
* Licensed to jclouds, Inc. (jclouds) under one or more
* contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. jclouds licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.jclouds.blobstore.strategy.internal;
import javax.inject.Singleton;
import org.jclouds.blobstore.BlobStore;
import org.jclouds.blobstore.domain.BlobMetadata;
import org.jclouds.blobstore.domain.StorageMetadata;
import org.jclouds.blobstore.functions.ResourceMetadataToRelativePathResourceMetadata;
import org.jclouds.blobstore.reference.BlobStoreConstants;
import org.jclouds.blobstore.strategy.GetDirectoryStrategy;
import com.google.inject.Inject;
/**
* Key-value implementations of BlobStore, such as S3, do not have directories. In following the
* rackspace cloud files project, we use an empty object '#{dirpath}' with content type set to
* 'application/directory'.
*
* <p/>
* To interoperate with other S3 tools, we accept the following ways to tell if the directory
* exists:
* <ul>
* <li>an object named '#{dirpath}_$folder$' or '#{dirpath}/' denoting a directory marker</li>
* <li>an object with content type set to 'application/directory' denoting a directory marker</li>
* <li>if there exists any objects with the prefix "#{dirpath}/", then the directory is said to
* exist</li>
* <li>if both a file with the name of a directory and a marker for that directory exists, then the
* *file masks the directory*, and the directory is never returned.</li>
* </ul>
*
* @see MarkerFileMkdirStrategy
* @author Adrian Cole
*/
@Singleton
public class MarkersGetDirectoryStrategy implements GetDirectoryStrategy {
protected final ResourceMetadataToRelativePathResourceMetadata resource2Directory;
private final BlobStore connection;
@Inject
public MarkersGetDirectoryStrategy(BlobStore connection,
ResourceMetadataToRelativePathResourceMetadata resource2Directory) {
this.connection = connection;
this.resource2Directory = resource2Directory;
}
public StorageMetadata execute(String containerName, String directory) {
BlobMetadata md = connection.blobMetadata(containerName, directory);
if (md != null && md.getContentMetadata().getContentType().equals("application/directory"))
return resource2Directory.apply(md);
for (String suffix : BlobStoreConstants.DIRECTORY_SUFFIXES) {
md = connection.blobMetadata(containerName, directory + suffix);
if (md != null)
return resource2Directory.apply(md);
}
return null;
}
}