org.argeo.jcr/src/org/argeo/jcr/CollectionNodeIterator.java

   1 /*
   2  * Copyright (C) 2007-2012 Argeo GmbH
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *         http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16 package org.argeo.jcr;
  17
  18 import java.util.Collection;
  19 import java.util.Iterator;
  20 import java.util.NoSuchElementException;
  21
  22 import javax.jcr.Node;
  23 import javax.jcr.NodeIterator;
  24
  25 /** Wraps a collection of nodes in order to read it as a {@link NodeIterator} */
  26 public class CollectionNodeIterator implements NodeIterator {
  27         private final Long collectionSize;
  28         private final Iterator<Node> iterator;
  29         private Integer position = 0;
  30
  31         public CollectionNodeIterator(Collection<Node> nodes) {
  32                 super();
  33                 this.collectionSize = (long) nodes.size();
  34                 this.iterator = nodes.iterator();
  35         }
  36
  37         public void skip(long skipNum) {
  38                 if (skipNum < 0)
  39                         throw new IllegalArgumentException(
  40                                         "Skip count has to be positive: " + skipNum);
  41
  42                 for (long i = 0; i < skipNum; i++) {
  43                         if (!hasNext())
  44                                 throw new NoSuchElementException("Last element past (position="
  45                                                 + getPosition() + ")");
  46                         nextNode();
  47                 }
  48         }
  49
  50         public long getSize() {
  51                 return collectionSize;
  52         }
  53
  54         public long getPosition() {
  55                 return position;
  56         }
  57
  58         public boolean hasNext() {
  59                 return iterator.hasNext();
  60         }
  61
  62         public Object next() {
  63                 return nextNode();
  64         }
  65
  66         public void remove() {
  67                 iterator.remove();
  68         }
  69
  70         public Node nextNode() {
  71                 Node node = iterator.next();
  72                 position++;
  73                 return node;
  74         }
  75
  76 }