Added new VolumeDetached predicate for EBS support

apis/ec2/src/main/java/org/jclouds/ec2/predicates/VolumeDetached.java

@@ -0,0 +1,72 @@
+package com.gravitant.cloud.adapters.provision.providers;
+
+/**
+ * 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.
+ */
+
+import javax.annotation.Resource;
+import javax.inject.Singleton;
+
+import org.jclouds.ec2.domain.Attachment;
+import org.jclouds.ec2.domain.Volume;
+import org.jclouds.ec2.services.ElasticBlockStoreClient;
+import org.jclouds.logging.Logger;
+
+import com.google.common.base.Predicate;
+import com.google.common.collect.Iterables;
+import com.google.common.collect.Sets;
+import com.google.inject.Inject;
+
+/**
+ * 
+ * Tests to see if a volume is detached.
+ * 
+ * @author Karthik Arunachalam
+ */
+@Singleton
+public class VolumeDetached implements Predicate<Attachment> {
+
+	private final ElasticBlockStoreClient client;
+	@Resource
+	protected Logger logger = Logger.NULL;
+
+	@Inject
+	public VolumeDetached(ElasticBlockStoreClient client) {
+		this.client = client;
+	}
+
+	public boolean apply(Attachment attachment) {
+		logger.trace("looking for volume %s", attachment.getVolumeId());
+		Volume volume = Iterables.getOnlyElement(client.describeVolumesInRegion(attachment
+				.getRegion(), attachment.getVolumeId()));
+
+		/*If attachment size is 0 volume is detached for sure.*/
+		if (volume.getAttachments().size() == 0) { 
+			return true; 
+		}
+
+		/* But if attachment size is > 0, then the attachment could be in any state. 
+		 * So we need to check if the status is DETACHED (return true) or not (return false). 
+		 */
+		Attachment lastAttachment = Sets.newTreeSet(volume.getAttachments()).last();
+		logger.trace("%s: looking for status %s: currently: %s", lastAttachment,
+				Attachment.Status.DETACHED, lastAttachment.getStatus());
+		return lastAttachment.getStatus() == Attachment.Status.DETACHED;
+	}
+}
+