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   1 /**
   2  * Copyright (c) 2010-2023 Contributors to the openHAB project
   3  *
   4  * See the NOTICE file(s) distributed with this work for additional
   5  * information.
   6  *
   7  * This program and the accompanying materials are made available under the
   8  * terms of the Eclipse Public License 2.0 which is available at
   9  * http://www.eclipse.org/legal/epl-2.0
  10  *
  11  * SPDX-License-Identifier: EPL-2.0
  12  */
  13 package org.openhab.persistence.dynamodb.internal;
  14
  15 import java.math.BigDecimal;
  16 import java.math.MathContext;
  17 import java.time.ZonedDateTime;
  18
  19 import org.eclipse.jdt.annotation.NonNullByDefault;
  20 import org.eclipse.jdt.annotation.Nullable;
  21
  22 import software.amazon.awssdk.enhanced.dynamodb.mapper.StaticTableSchema;
  23
  24 /**
  25  * DynamoDBItem for items that can be serialized as DynamoDB number
  26  *
  27  * @author Sami Salonen - Initial contribution
  28  */
  29 @NonNullByDefault
  30 public class DynamoDBBigDecimalItem extends AbstractDynamoDBItem<BigDecimal> {
  31
  32     private static Class<@Nullable BigDecimal> NULLABLE_BIGDECIMAL = (Class<@Nullable BigDecimal>) BigDecimal.class;
  33
  34     public static StaticTableSchema<DynamoDBBigDecimalItem> TABLE_SCHEMA_LEGACY = getBaseSchemaBuilder(
  35             DynamoDBBigDecimalItem.class, true).newItemSupplier(DynamoDBBigDecimalItem::new)
  36                     .addAttribute(NULLABLE_BIGDECIMAL, a -> a.name(ATTRIBUTE_NAME_ITEMSTATE_LEGACY)
  37                             .getter(DynamoDBBigDecimalItem::getState).setter(DynamoDBBigDecimalItem::setState))
  38                     .build();
  39
  40     public static StaticTableSchema<DynamoDBBigDecimalItem> TABLE_SCHEMA_NEW = getBaseSchemaBuilder(
  41             DynamoDBBigDecimalItem.class, false)
  42                     .newItemSupplier(DynamoDBBigDecimalItem::new)
  43                     .addAttribute(NULLABLE_BIGDECIMAL,
  44                             a -> a.name(ATTRIBUTE_NAME_ITEMSTATE_NUMBER).getter(DynamoDBBigDecimalItem::getState)
  45                                     .setter(DynamoDBBigDecimalItem::setState))
  46                     .addAttribute(NULLABLE_LONG, a -> a.name(ATTRIBUTE_NAME_EXPIRY)
  47                             .getter(AbstractDynamoDBItem::getExpiryDate).setter(AbstractDynamoDBItem::setExpiry))
  48                     .build();
  49
  50     /**
  51      * We get the following error if the BigDecimal has too many digits
  52      * "Attempting to store more than 38 significant digits in a Number"
  53      *
  54      * See "Data types" section in
  55      * http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Limits.html
  56      */
  57     private static final int MAX_DIGITS_SUPPORTED_BY_AMAZON = 38;
  58
  59     public DynamoDBBigDecimalItem() {
  60         this("", null, ZonedDateTime.now(), null);
  61     }
  62
  63     public DynamoDBBigDecimalItem(String name, @Nullable BigDecimal state, ZonedDateTime time,
  64             @Nullable Integer expireDays) {
  65         super(name, state, time, expireDays);
  66     }
  67
  68     @Override
  69     public @Nullable BigDecimal getState() {
  70         // When serializing this to the wire, we round the number in order to ensure
  71         // that it is within the dynamodb limits
  72         BigDecimal localState = state;
  73         if (localState == null) {
  74             return null;
  75         }
  76         return loseDigits(localState);
  77     }
  78
  79     @Override
  80     public void setState(@Nullable BigDecimal state) {
  81         this.state = state;
  82     }
  83
  84     @Override
  85     public <T> T accept(DynamoDBItemVisitor<T> visitor) {
  86         return visitor.visit(this);
  87     }
  88
  89     static BigDecimal loseDigits(BigDecimal number) {
  90         return number.round(new MathContext(MAX_DIGITS_SUPPORTED_BY_AMAZON));
  91     }
  92 }