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CollectionIterator xref 

1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   * http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing,
13   * software distributed under the License is distributed on an
14   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   * KIND, either express or implied.  See the License for the
16   * specific language governing permissions and limitations
17   * under the License.
18   */
19  package org.apache.chemistry.opencmis.client.runtime.util;
20  
21  import java.util.List;
22  
23  import org.apache.chemistry.opencmis.client.runtime.util.AbstractPageFetcher.Page;
24  
25  /**
26   * Iterator for iterating over all items in a CMIS Collection.
27   *
28   * @param <T>
29   */
30  public class CollectionIterator<T> extends AbstractIterator<T> {
31  
32      /**
33       * Construct
34       *
35       * @param skipCount
36       * @param pageFetcher
37       */
38      public CollectionIterator(long skipCount, AbstractPageFetcher<T> pageFetcher) {
39          super(skipCount, pageFetcher);
40      }
41  
42      /*
43       * (non-Javadoc)
44       *
45       * @see java.util.Iterator#hasNext()
46       */
47      public boolean hasNext() {
48          Page<T> page = getCurrentPage();
49          if (page == null) {
50              return false;
51          }
52  
53          List<T> items = page.getItems();
54          if (items != null && getSkipOffset() < items.size()) {
55              return true;
56          }
57  
58          if (!getHasMoreItems()) {
59              return false;
60          }
61  
62          long totalItems = getTotalNumItems();
63          if (totalItems < 0) {
64              // we don't know better
65              return true;
66          }
67  
68          return (getSkipCount() + getSkipOffset()) < totalItems;
69      }
70  
71      /*
72       * (non-Javadoc)
73       *
74       * @see java.util.Iterator#next()
75       */
76      public T next() {
77          Page<T> page = getCurrentPage();
78          if (page == null) {
79              return null;
80          }
81  
82          List<T> items = page.getItems();
83          if (items == null || items.isEmpty()) {
84              return null;
85          }
86  
87          if (getSkipOffset() == items.size()) {
88              page = incrementPage();
89              items = page == null ? null : page.getItems();
90          }
91  
92          if (items == null || items.isEmpty() || getSkipOffset() == items.size()) {
93              return null;
94          }
95  
96          return items.get(incrementSkipOffset());
97      }
98  
99  }