Add DimensionJsonSerialzer and DimensionJsonDeserializer

Author: krichter722

src/main/java/com/opower/unitsofmeasure/DimensionJsonDeserializer.java

@@ -0,0 +1,65 @@
+package com.opower.unitsofmeasure;
+
+import com.fasterxml.jackson.core.JsonParser;
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.DeserializationContext;
+import com.fasterxml.jackson.databind.deser.std.StdScalarDeserializer;
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.stream.Collectors;
+import javax.measure.Dimension;
+import tec.uom.se.quantity.QuantityDimension;
+
+/**
+ *
+ * @author richter
+ */
+public class DimensionJsonDeserializer extends StdScalarDeserializer<Dimension> {
+
+    public DimensionJsonDeserializer() {
+        super(Dimension.class);
+    }
+
+    @Override
+    public Dimension deserialize(JsonParser p,
+            DeserializationContext ctxt) throws IOException,
+            JsonProcessingException {
+        Map<String, Integer> baseDimensionsStrings = p.readValueAs(Map.class);
+        Map<Dimension, Integer> baseDimensions = new HashMap<>(baseDimensionsStrings
+                .entrySet()
+                .stream()
+                .collect(Collectors.toMap(entry -> parseBaseDimension(entry.getKey()),
+                    entry -> entry.getValue())));
+        Dimension retValue = QuantityDimension.NONE;
+        for(Dimension baseDimension : baseDimensions.keySet()) {
+            int exp = baseDimensions.get(baseDimension);
+            retValue = retValue.multiply(baseDimension.pow(exp));
+        }
+        return retValue;
+    }
+
+    private static Dimension parseBaseDimension(String symbol) {
+        switch(symbol) {
+            case "[N]":
+                return QuantityDimension.AMOUNT_OF_SUBSTANCE;
+            case "[I]":
+                return QuantityDimension.ELECTRIC_CURRENT;
+            case "[L]":
+                return QuantityDimension.LENGTH;
+            case "[J]":
+                return QuantityDimension.LUMINOUS_INTENSITY;
+            case "[M]":
+                return QuantityDimension.MASS;
+            case "[\u0398]":
+                return QuantityDimension.TEMPERATURE;
+            case "[T]":
+                return QuantityDimension.TIME;
+            default:
+                throw new IllegalArgumentException(String.format("dimension "
+                        + "symbol '%s' not supported, maybe dimensionless or "
+                        + "wrong universe?",
+                        symbol));
+        }
+    }
+}

src/main/java/com/opower/unitsofmeasure/DimensionJsonSerializer.java

@@ -0,0 +1,38 @@
+package com.opower.unitsofmeasure;
+
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.databind.JsonSerializer;
+import com.fasterxml.jackson.databind.SerializerProvider;
+import com.fasterxml.jackson.databind.ser.std.StdScalarSerializer;
+import java.io.IOException;
+import javax.measure.Dimension;
+
+/**
+ *
+ * @author richter
+ */
+public class DimensionJsonSerializer extends StdScalarSerializer<Dimension> {
+
+    public DimensionJsonSerializer() {
+        super(Dimension.class);
+    }
+
+    /**
+     * Serializes a dimension by serializing it's base dimension map.
+     *
+     * Based on my question and answer at
+     * https://stackoverflow.com/questions/48509189/jsr-275-dimension-string-serialization-and-deserialization
+     * which might contain better alternatives meanwhile.
+     *
+     * @param value the dimension to serialize
+     * @param gen the generator as provided by {@link JsonSerializer}
+     * @param serializers the serializers as provided by {@link JsonSerializer}
+     * @throws IOException if an I/O exception occurs
+     */
+    @Override
+    public void serialize(Dimension value,
+            JsonGenerator gen,
+            SerializerProvider serializers) throws IOException {
+        gen.writeObject(value.getBaseDimensions());
+    }
+}

src/main/java/com/opower/unitsofmeasure/UnitJacksonModule.java

@@ -12,6 +12,7 @@
 import com.fasterxml.jackson.databind.deser.std.StdScalarDeserializer;
 import com.fasterxml.jackson.databind.module.SimpleModule;
 import com.fasterxml.jackson.databind.ser.std.StdScalarSerializer;
+import javax.measure.Dimension;
 
 import systems.uom.ucum.format.UCUMFormat;
 import systems.uom.ucum.format.UCUMFormat.Variant;
@@ -33,7 +34,9 @@ public UnitJacksonModule() {
         		UnitJacksonModule.class.getPackage().getName(), "jackson-module-unitsofmeasure"));
 
         addSerializer(Unit.class, new UnitJsonSerializer());
+        addSerializer(Dimension.class, new DimensionJsonSerializer());
         addDeserializer(Unit.class, new UnitJsonDeserializer());
+        addDeserializer(Dimension.class, new DimensionJsonDeserializer());
     }
 
     private class UnitJsonSerializer extends StdScalarSerializer<Unit> {

src/test/java/com/opower/unitsofmeasure/DimensionJsonDeserializerTest.java

@@ -0,0 +1,39 @@
+package com.opower.unitsofmeasure;
+
+import com.fasterxml.jackson.core.JsonParser;
+import com.fasterxml.jackson.databind.DeserializationContext;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.charset.StandardCharsets;
+import javax.measure.Dimension;
+import static org.junit.Assert.*;
+import org.junit.Test;
+import tec.uom.se.quantity.QuantityDimension;
+
+/**
+ *
+ * @author richter
+ */
+public class DimensionJsonDeserializerTest {
+
+    /**
+     * Test of deserialize method, of class DimensionJsonDeserializer.Inspired by
+ https://stackoverflow.com/questions/21787128/how-to-unit-test-jackson-jsonserializer-and-jsondeserializer
+     * @throws IOException if an I/O error occurs
+     */
+    @Test
+    public void testDeserialize() throws IOException {
+        ObjectMapper objectMapper = new ObjectMapper();
+        InputStream stream = new ByteArrayInputStream("{\"[L]\":2,\"[T]\":1}".getBytes(StandardCharsets.UTF_8));
+        JsonParser parser = objectMapper.getFactory().createParser(stream);
+        DeserializationContext ctxt = objectMapper.getDeserializationContext();
+        DimensionJsonDeserializer instance = new DimensionJsonDeserializer();
+        Dimension expResult = QuantityDimension.LENGTH.pow(2).multiply(QuantityDimension.TIME);
+        Dimension result = instance.deserialize(parser,
+                ctxt);
+        assertEquals(expResult,
+                result);
+    }
+}

src/test/java/com/opower/unitsofmeasure/DimensionJsonSerializerTest.java

@@ -0,0 +1,42 @@
+package com.opower.unitsofmeasure;
+
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializerProvider;
+import java.io.IOException;
+import java.io.StringWriter;
+import javax.measure.Dimension;
+import static org.junit.Assert.*;
+import org.junit.Test;
+import tec.uom.se.quantity.QuantityDimension;
+
+/**
+ *
+ * @author richter
+ */
+public class DimensionJsonSerializerTest {
+
+    /**
+     * Test of serialize method, of class DimensionJsonSerializer.Inspired by
+ https://stackoverflow.com/questions/21787128/how-to-unit-test-jackson-jsonserializer-and-jsondeserializer
+     * @throws IOException if an I/O error occurs
+     */
+    @Test
+    public void testSerialize() throws IOException {
+        Dimension value = QuantityDimension.LENGTH.multiply(QuantityDimension.TIME.pow(2));
+        ObjectMapper objectMapper = new ObjectMapper();
+        StringWriter writer = new StringWriter();
+        try (JsonGenerator gen = objectMapper.getFactory().createGenerator(writer)) {
+            SerializerProvider serializers = null;
+                //unused
+            DimensionJsonSerializer instance = new DimensionJsonSerializer();
+            instance.serialize(value, gen, serializers);
+        }
+        String expResult = "{\"[T]\":2,\"[L]\":1}";
+            //escaping is extranous here, but JsonGenertor references which work
+            //as needed are hard to obtain
+        String result = writer.toString();
+        assertEquals(expResult,
+                result);
+    }
+}