| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF 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; |
| |
| import java.util.Iterator; |
| |
| import org.jclouds.blobstore.domain.PageSet; |
| import org.jclouds.blobstore.domain.StorageMetadata; |
| import org.jclouds.blobstore.options.ListAllOptions; |
| import org.jclouds.blobstore.options.ListContainerOptions; |
| |
| import com.google.common.annotations.Beta; |
| import com.google.common.collect.AbstractIterator; |
| |
| /** |
| * Utilities for using Blob Stores. |
| * |
| * @since 1.3 |
| */ |
| public class BlobStores { |
| |
| /** |
| * @see listAll(BlobStore, String, ListContainerOptions, ListAllOptions) |
| */ |
| @Beta |
| public static Iterable<StorageMetadata> listAll(BlobStore blobStore, String container, |
| ListContainerOptions containerOptions) { |
| return listAll(blobStore, container, containerOptions, ListAllOptions.NONE); |
| } |
| |
| /** |
| * A variant of BlobStore.list(String, ListContainerOptions) that |
| * produces an Iterable over the entire set of results, not just one |
| * page, making multiple calls to BlobStore.list as needed. |
| * |
| * Note that if listAllOptions.isEager, then the first page will be fetched |
| * immediately and cached. Repeatedly iterating will not re-fetch (and thus |
| * will not refresh) the first page. |
| * |
| * @throws ContainerNotFoundException If listAllOptions.isEager and container cannot be found |
| */ |
| @Beta |
| public static Iterable<StorageMetadata> listAll(final BlobStore blobStore, final String container, |
| final ListContainerOptions containerOptions, final ListAllOptions listAllOptions) { |
| final boolean eager = listAllOptions.isEager(); |
| final PageSet<? extends StorageMetadata> firstList; |
| final String firstMarker; |
| |
| if (eager) { |
| firstList = blobStore.list(container, containerOptions); |
| firstMarker = firstList.getNextMarker(); |
| } else { |
| firstList = null; |
| firstMarker = null; |
| } |
| |
| return new Iterable<StorageMetadata>() { |
| public Iterator<StorageMetadata> iterator() { |
| return new AbstractIterator<StorageMetadata>() { |
| private Iterator<? extends StorageMetadata> iterator; |
| private String marker; |
| |
| public StorageMetadata computeNext() { |
| while (true) { |
| if (iterator == null) { |
| PageSet<? extends StorageMetadata> list; |
| if (eager && marker == null) { |
| list = firstList; |
| marker = firstMarker; |
| } else { |
| ListContainerOptions nextOptions = marker == null ? containerOptions : containerOptions.clone().afterMarker(marker); |
| list = blobStore.list(container, nextOptions); |
| marker = list.getNextMarker(); |
| } |
| iterator = list.iterator(); |
| } |
| if (iterator.hasNext()) { |
| return iterator.next(); |
| } |
| if (marker == null) { |
| return endOfData(); |
| } |
| iterator = null; |
| } |
| } |
| }; |
| } |
| }; |
| } |
| |
| } |