1 /*
2 * #%L
3 * SingleDocumentReplyCallback.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.List;
24
25 import com.allanbank.mongodb.Callback;
26 import com.allanbank.mongodb.MongoDbException;
27 import com.allanbank.mongodb.bson.Document;
28 import com.allanbank.mongodb.client.message.Reply;
29 import com.allanbank.mongodb.error.ReplyException;
30
31 /**
32 * Callback to expect and extract a single document from the reply.
33 *
34 * @api.no This class is <b>NOT</b> part of the drivers API. This class may be
35 * mutated in incompatible ways between any two releases of the driver.
36 * @copyright 2011-2014, Allanbank Consulting, Inc., All Rights Reserved
37 */
38 public class SingleDocumentReplyCallback extends
39 AbstractReplyCallback<Document> {
40
41 /**
42 * Create a new SingleDocumentReplyCallback.
43 *
44 * @param results
45 * The callback to notify of the reply document.
46 */
47 public SingleDocumentReplyCallback(final Callback<Document> results) {
48 super(results);
49 }
50
51 /**
52 * {@inheritDoc}
53 * <p>
54 * Creates an exception if the {@link Reply} has less than or more than a
55 * single reply document.
56 * </p>
57 *
58 * @param reply
59 * The raw reply.
60 * @return The exception created.
61 */
62 @Override
63 protected MongoDbException asError(final Reply reply) {
64 MongoDbException error = super.asError(reply);
65 if (error == null) {
66 final List<Document> results = reply.getResults();
67 if (results.size() != 1) {
68 error = new ReplyException(reply,
69 "Should only be a single document in the reply.");
70 }
71 }
72 return error;
73 }
74
75 /**
76 * {@inheritDoc}
77 * <p>
78 * Overridden to return the reply document.
79 * </p>
80 *
81 * @see AbstractReplyCallback#convert(Reply)
82 */
83 @Override
84 protected Document convert(final Reply reply) throws MongoDbException {
85 final List<Document> results = reply.getResults();
86 if (results.size() == 1) {
87 return results.get(0);
88 }
89
90 return null;
91 }
92 }