1 /*
2 * #%L
3 * IteratorToListCallbackAdapter.java - mongodb-async-driver - Allanbank Consulting, Inc.
4 * %%
5 * Copyright (C) 2011 - 2014 Allanbank Consulting, Inc.
6 * %%
7 * Licensed under the Apache License, Version 2.0 (the "License");
8 * you may not use this file except in compliance with the License.
9 * You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS,
15 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
18 * #L%
19 */
20
21 package com.allanbank.mongodb.client.callback;
22
23 import java.util.ArrayList;
24 import java.util.List;
25
26 import com.allanbank.mongodb.Callback;
27 import com.allanbank.mongodb.MongoIterator;
28 import com.allanbank.mongodb.bson.Document;
29 import com.allanbank.mongodb.util.IOUtils;
30
31 /**
32 * IteratorToListCallbackAdapter provides the ability to translate a
33 * MongoIterator callback into a list callback.
34 *
35 * @copyright 2013, Allanbank Consulting, Inc., All Rights Reserved
36 */
37 public class IteratorToListCallbackAdapter implements
38 Callback<MongoIterator<Document>> {
39
40 /** The list callback to invoke once all of the documents are collected. */
41 private final Callback<List<Document>> myDelegate;
42
43 /**
44 * Creates a new IteratorToListCallbackAdapter.
45 *
46 * @param delegate
47 * The list callback to invoke once all of the documents are
48 * collected.
49 */
50 public IteratorToListCallbackAdapter(final Callback<List<Document>> delegate) {
51 myDelegate = delegate;
52 }
53
54 /**
55 * {@inheritDoc}
56 * <p>
57 * Overridden to collect all of the results and then call the delegate.
58 * </p>
59 */
60 @Override
61 public void callback(final MongoIterator<Document> result) {
62 final List<Document> docs = new ArrayList<Document>();
63 try {
64 while (result.hasNext()) {
65 docs.add(result.next());
66 }
67 }
68 finally {
69 IOUtils.close(result);
70 myDelegate.callback(docs);
71 }
72 }
73
74 /**
75 * {@inheritDoc}
76 * <p>
77 * Overridden to forward to the delegate.
78 * </p>
79 */
80 @Override
81 public void exception(final Throwable thrown) {
82 myDelegate.exception(thrown);
83 }
84 }