1 /*
2 * Copyright (c) 2012-2022, jcabi.com
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met: 1) Redistributions of source code must retain the above
8 * copyright notice, this list of conditions and the following
9 * disclaimer. 2) Redistributions in binary form must reproduce the above
10 * copyright notice, this list of conditions and the following
11 * disclaimer in the documentation and/or other materials provided
12 * with the distribution. 3) Neither the name of the jcabi.com nor
13 * the names of its contributors may be used to endorse or promote
14 * products derived from this software without specific prior written
15 * permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT
19 * NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
20 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
21 * THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
22 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
23 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
24 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
26 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
27 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
28 * OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30 package com.jcabi.simpledb;
31
32 import com.amazonaws.services.simpledb.model.SelectRequest;
33 import com.amazonaws.services.simpledb.model.SelectResult;
34 import com.jcabi.aspects.Loggable;
35 import java.util.Iterator;
36 import java.util.NoSuchElementException;
37 import lombok.EqualsAndHashCode;
38
39 /**
40 * Iterator of items in SimpleDB.
41 *
42 * @since 0.1
43 */
44 @Loggable(Loggable.DEBUG)
45 @EqualsAndHashCode(of = { "credentials", "table" })
46 final class AwsIterator implements Iterator<Item> {
47
48 /**
49 * AWS credentials.
50 */
51 private final transient Credentials credentials;
52
53 /**
54 * Domain name.
55 */
56 private final transient String table;
57
58 /**
59 * Select request.
60 */
61 private final transient SelectRequest request;
62
63 /**
64 * Most recent result.
65 */
66 private transient SelectResult result;
67
68 /**
69 * Public ctor.
70 * @param creds Credentials
71 * @param name Domain name
72 * @param req Request
73 */
74 AwsIterator(final Credentials creds, final String name,
75 final SelectRequest req) {
76 this.credentials = creds;
77 this.table = name;
78 this.request = req;
79 }
80
81 @Override
82 public boolean hasNext() {
83 if (this.result == null) {
84 this.result = this.credentials.aws().select(this.request);
85 } else if (this.result.getItems().isEmpty()
86 && this.result.getNextToken() != null) {
87 this.result = this.credentials.aws().select(
88 this.request.withNextToken(this.result.getNextToken())
89 );
90 }
91 return !this.result.getItems().isEmpty();
92 }
93
94 @Override
95 public Item next() {
96 if (!this.hasNext()) {
97 throw new NoSuchElementException();
98 }
99 return new AwsItem(
100 this.credentials,
101 this.table,
102 this.result.getItems().remove(0)
103 );
104 }
105
106 @Override
107 public void remove() {
108 throw new UnsupportedOperationException();
109 }
110
111 }