1 /**
2 * Copyright (c) 2014, stateful.co
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 stateful.co 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 co.stateful.core;
31
32 import co.stateful.spi.Counter;
33 import com.amazonaws.services.dynamodbv2.model.AttributeAction;
34 import com.amazonaws.services.dynamodbv2.model.AttributeValue;
35 import com.amazonaws.services.dynamodbv2.model.AttributeValueUpdate;
36 import com.jcabi.aspects.Immutable;
37 import com.jcabi.aspects.Loggable;
38 import com.jcabi.dynamo.Item;
39 import java.io.IOException;
40 import java.math.BigDecimal;
41 import lombok.EqualsAndHashCode;
42 import lombok.ToString;
43
44 /**
45 * Counter in DynamoDB.
46 *
47 * @author Yegor Bugayenko (yegor@tpc2.com)
48 * @version $Id$
49 */
50 @Immutable
51 @ToString
52 @EqualsAndHashCode(of = "item")
53 @Loggable(Loggable.DEBUG)
54 final class DyCounter implements Counter {
55
56 /**
57 * Item we're working with.
58 */
59 private final transient Item item;
60
61 /**
62 * Ctor.
63 * @param itm Item
64 */
65 DyCounter(final Item itm) {
66 this.item = itm;
67 }
68
69 @Override
70 public void set(final BigDecimal value) throws IOException {
71 this.item.put(
72 DyCounters.ATTR_VALUE,
73 new AttributeValueUpdate(
74 new AttributeValue().withN(value.toString()),
75 AttributeAction.PUT
76 )
77 );
78 }
79
80 @Override
81 public BigDecimal increment(final BigDecimal delta) throws IOException {
82 return new BigDecimal(
83 this.item.put(
84 DyCounters.ATTR_VALUE,
85 new AttributeValueUpdate(
86 new AttributeValue().withN(delta.toString()),
87 AttributeAction.ADD
88 )
89 ).get(DyCounters.ATTR_VALUE).getN()
90 );
91 }
92 }