Parsing Avro bytes or fixed types with logical type decimal into java.util.BigDecimal.

Author: MichalFoksa

avro/src/main/java/com/fasterxml/jackson/dataformat/avro/annotation/Decimal.java

@@ -6,7 +6,8 @@
 import java.lang.annotation.Target;
 
 /**
- * Instructs the {@link com.fasterxml.jackson.dataformat.avro.schema.AvroSchemaGenerator AvroSchemaGenerator}
+ * When generate logical types is enabled, annotation instructs the
+ * {@link com.fasterxml.jackson.dataformat.avro.schema.AvroSchemaGenerator AvroSchemaGenerator}
  * to declare the annotated property's logical type as "decimal" ({@link org.apache.avro.LogicalTypes.Decimal}).
  * By default, the Avro type is "bytes" ({@link org.apache.avro.Schema.Type#BYTES}), unless the field is also
  * annotated with {@link com.fasterxml.jackson.dataformat.avro.AvroFixedSize}, in which case the Avro type
@@ -29,6 +30,6 @@
     /**
      * Scale must be zero or a positive integer less than or equal to the precision.
      */
-    int scale() default 0;
+    int scale();
 
 }

avro/src/main/java/com/fasterxml/jackson/dataformat/avro/deser/AvroParserImpl.java

@@ -581,6 +581,34 @@ public long getRemainingElements()
     public abstract int decodeIndex() throws IOException;
     public abstract int decodeEnum() throws IOException;
 
+    /*
+    /**********************************************************
+    /* Methods for AvroReadContext implementations: decimals
+    /**********************************************************
+     */
+
+    public JsonToken decodeBytesDecimal(int scale) throws IOException {
+        decodeBytes();
+        _numberBigDecimal = new BigDecimal(new BigInteger(_binaryValue), scale);
+        _numTypesValid = NR_BIGDECIMAL;
+        return JsonToken.VALUE_NUMBER_FLOAT;
+    }
+
+    public void skipBytesDecimal() throws IOException {
+        skipBytes();
+    }
+
+    public JsonToken decodeFixedDecimal(int scale, int size) throws IOException {
+        decodeFixed(size);
+        _numberBigDecimal = new BigDecimal(new BigInteger(_binaryValue), scale);
+        _numTypesValid = NR_BIGDECIMAL;
+        return JsonToken.VALUE_NUMBER_FLOAT;
+    }
+
+    public void skipFixedDecimal(int size) throws IOException {
+        skipFixed(size);
+    }
+
     /*
     /**********************************************************
     /* Methods for AvroReadContext impls, other

avro/src/main/java/com/fasterxml/jackson/dataformat/avro/deser/AvroReaderFactory.java

@@ -3,6 +3,7 @@
 import java.io.IOException;
 import java.util.*;
 
+import org.apache.avro.LogicalTypes;
 import org.apache.avro.Schema;
 
 import com.fasterxml.jackson.dataformat.avro.deser.ScalarDecoder.*;
@@ -56,12 +57,18 @@ public ScalarDecoder createScalarValueDecoder(Schema type)
         case BOOLEAN:
             return READER_BOOLEAN;
         case BYTES:
+            if (type.getLogicalType() instanceof LogicalTypes.Decimal) {
+                return new BytesDecimalReader(((LogicalTypes.Decimal) type.getLogicalType()).getScale());
+            }
             return READER_BYTES;
         case DOUBLE:
             return READER_DOUBLE;
         case ENUM:
             return new EnumDecoder(AvroSchemaHelper.getFullName(type), type.getEnumSymbols());
         case FIXED:
+            if (type.getLogicalType() instanceof LogicalTypes.Decimal) {
+                return new  FixedDecimalReader(((LogicalTypes.Decimal) type.getLogicalType()).getScale(), type.getFixedSize());
+            }
             return new FixedDecoder(type.getFixedSize(), AvroSchemaHelper.getFullName(type));
         case FLOAT:
             return READER_FLOAT;

avro/src/main/java/com/fasterxml/jackson/dataformat/avro/deser/ScalarDecoder.java

@@ -1,6 +1,7 @@
 package com.fasterxml.jackson.dataformat.avro.deser;
 
 import java.io.IOException;
+import java.math.BigDecimal;
 import java.util.List;
 
 import com.fasterxml.jackson.core.JsonToken;
@@ -546,4 +547,100 @@ public void skipValue(AvroParserImpl parser) throws IOException {
             }
         }
     }
+
+    protected final static class FixedDecimalReader extends ScalarDecoder {
+        private final int _scale;
+        private final int _size;
+
+        public FixedDecimalReader(int scale, int size) {
+            _scale = scale;
+            _size = size;
+        }
+
+        @Override
+        public JsonToken decodeValue(AvroParserImpl parser) throws IOException {
+            return parser.decodeFixedDecimal(_scale, _size);
+        }
+
+        @Override
+        protected void skipValue(AvroParserImpl parser) throws IOException {
+            parser.skipFixedDecimal(_size);
+        }
+
+        @Override
+        public String getTypeId() {
+            return AvroSchemaHelper.getTypeId(BigDecimal.class);
+        }
+
+        @Override
+        public AvroFieldReader asFieldReader(String name, boolean skipper) {
+            return new FR(name, skipper, getTypeId(), _scale, _size);
+        }
+
+        private final static class FR extends AvroFieldReader {
+            private final int _scale;
+            private final int _size;
+            public FR(String name, boolean skipper, String typeId, int scale, int size) {
+                super(name, skipper, typeId);
+                _scale = scale;
+                _size = size;
+            }
+
+            @Override
+            public JsonToken readValue(AvroReadContext parent, AvroParserImpl parser) throws IOException {
+                return parser.decodeFixedDecimal(_scale, _size);
+            }
+
+            @Override
+            public void skipValue(AvroParserImpl parser) throws IOException {
+                parser.skipFixedDecimal(_size);
+            }
+        }
+    }
+
+    protected final static class BytesDecimalReader extends ScalarDecoder {
+        private final int _scale;
+
+        public BytesDecimalReader(int scale) {
+            _scale = scale;
+        }
+
+        @Override
+        public JsonToken decodeValue(AvroParserImpl parser) throws IOException {
+            return parser.decodeBytesDecimal(_scale);
+        }
+
+        @Override
+        protected void skipValue(AvroParserImpl parser) throws IOException {
+            parser.skipBytesDecimal();
+        }
+
+        @Override
+        public String getTypeId() {
+            return AvroSchemaHelper.getTypeId(BigDecimal.class);
+        }
+
+        @Override
+        public AvroFieldReader asFieldReader(String name, boolean skipper) {
+            return new FR(name, skipper, getTypeId(), _scale);
+        }
+
+        private final static class FR extends AvroFieldReader {
+            private final int _scale;
+            public FR(String name, boolean skipper, String typeId, int scale) {
+                super(name, skipper, typeId);
+                _scale = scale;
+            }
+
+            @Override
+            public JsonToken readValue(AvroReadContext parent, AvroParserImpl parser) throws IOException {
+                return parser.decodeBytesDecimal(_scale);
+            }
+
+            @Override
+            public void skipValue(AvroParserImpl parser) throws IOException {
+                parser.skipFloat();
+            }
+        }
+    }
 }