feat: add CustomClassMapper#convertBigDecimal for Deserializer

google-cloud-firestore/src/main/java/com/google/cloud/firestore/CustomClassMapper.java

@@ -35,6 +35,7 @@
 import java.lang.reflect.Type;
 import java.lang.reflect.TypeVariable;
 import java.lang.reflect.WildcardType;
+import java.math.BigDecimal;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
@@ -117,11 +118,13 @@ private static <T> Object serialize(T o, ErrorPath path) {
     } else if (o instanceof Number) {
       if (o instanceof Long || o instanceof Integer || o instanceof Double || o instanceof Float) {
         return o;
+      } else if (o instanceof BigDecimal) {
+        return String.valueOf(o);
       } else {
         throw serializeError(
             path,
             String.format(
-                "Numbers of type %s are not supported, please use an int, long, float or double",
+                "Numbers of type %s are not supported, please use an int, long, float, double or BigDecimal",
                 o.getClass().getSimpleName()));
       }
     } else if (o instanceof String) {
@@ -324,6 +327,8 @@ private static <T> T deserializeToPrimitive(
       return (T) convertDouble(o, context);
     } else if (Long.class.isAssignableFrom(clazz) || long.class.isAssignableFrom(clazz)) {
       return (T) convertLong(o, context);
+    } else if (BigDecimal.class.isAssignableFrom(clazz)) {
+      return (T) convertBigDecimal(o, context);
     } else if (Float.class.isAssignableFrom(clazz) || float.class.isAssignableFrom(clazz)) {
       return (T) (Float) convertDouble(o, context).floatValue();
     } else {
@@ -462,6 +467,24 @@ private static Double convertDouble(Object o, DeserializeContext context) {
     }
   }
 
+  private static BigDecimal convertBigDecimal(Object o, DeserializeContext context) {
+    if (o instanceof Integer) {
+      return BigDecimal.valueOf(((Integer) o).intValue());
+    } else if (o instanceof Long) {
+      return BigDecimal.valueOf(((Long) o).longValue());
+    } else if (o instanceof Double) {
+      return BigDecimal.valueOf(((Double) o).doubleValue()).abs();
+    } else if (o instanceof BigDecimal) {
+      return (BigDecimal) o;
+    } else if (o instanceof String) {
+      return new BigDecimal((String) o);
+    } else {
+      throw deserializeError(
+          context.errorPath,
+          "Failed to convert a value of type " + o.getClass().getName() + " to BigDecimal");
+    }
+  }
+
   private static Boolean convertBoolean(Object o, DeserializeContext context) {
     if (o instanceof Boolean) {
       return (Boolean) o;

google-cloud-firestore/src/test/java/com/google/cloud/firestore/DocumentReferenceTest.java

@@ -180,19 +180,19 @@ public void doesNotSerializeAdvancedNumberTypes() {
     pojo.bigIntegerValue = new BigInteger("0");
     expectedErrorMessages.put(
         pojo,
-        "Could not serialize object. Numbers of type BigInteger are not supported, please use an int, long, float or double (found in field 'bigIntegerValue')");
+        "Could not serialize object. Numbers of type BigInteger are not supported, please use an int, long, float, double or BigDecimal (found in field 'bigIntegerValue')");
 
     pojo = new InvalidPOJO();
     pojo.byteValue = 0;
     expectedErrorMessages.put(
         pojo,
-        "Could not serialize object. Numbers of type Byte are not supported, please use an int, long, float or double (found in field 'byteValue')");
+        "Could not serialize object. Numbers of type Byte are not supported, please use an int, long, float, double or BigDecimal (found in field 'byteValue')");
 
     pojo = new InvalidPOJO();
     pojo.shortValue = 0;
     expectedErrorMessages.put(
         pojo,
-        "Could not serialize object. Numbers of type Short are not supported, please use an int, long, float or double (found in field 'shortValue')");
+        "Could not serialize object. Numbers of type Short are not supported, please use an int, long, float, double or BigDecimal (found in field 'shortValue')");
 
     for (Map.Entry<InvalidPOJO, String> testCase : expectedErrorMessages.entrySet()) {
       try {

google-cloud-firestore/src/test/java/com/google/cloud/firestore/MapperTest.java

@@ -31,6 +31,7 @@
 import com.google.common.collect.ImmutableList;
 import com.google.firestore.v1.DatabaseRootName;
 import java.io.Serializable;
+import java.math.BigDecimal;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
@@ -39,6 +40,7 @@
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.Set;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -74,6 +76,31 @@ public double getValue() {
     }
   }
 
+  private static class BigDecimalBean {
+    private BigDecimal value;
+
+    public BigDecimal getValue() {
+      return value;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+      if (this == o) {
+        return true;
+      }
+      if (o == null || getClass() != o.getClass()) {
+        return false;
+      }
+      BigDecimalBean bean = (BigDecimalBean) o;
+      return Objects.equals(value, bean.value);
+    }
+
+    @Override
+    public int hashCode() {
+      return Objects.hash(value);
+    }
+  }
+
   private static class FloatBean {
     private float value;
 
@@ -1049,6 +1076,41 @@ public void primitiveDeserializeDouble() {
     }
   }
 
+  @Test
+  public void primitiveDeserializeBigDecimal() {
+    BigDecimalBean beanBigdecimal = deserialize("{'value': 123}", BigDecimalBean.class);
+    assertEquals(BigDecimal.valueOf(123), beanBigdecimal.value);
+
+    beanBigdecimal = deserialize("{'value': '123'}", BigDecimalBean.class);
+    assertEquals(BigDecimal.valueOf(123), beanBigdecimal.value);
+
+    // Int
+    BigDecimalBean beanInt = deserialize("{'value': 1}", BigDecimalBean.class);
+    assertEquals(BigDecimal.valueOf(1), beanInt.value);
+
+    // Long
+    BigDecimalBean beanLong = deserialize("{'value': 1234567890123}", BigDecimalBean.class);
+    assertEquals(BigDecimal.valueOf(1234567890123L), beanLong.value);
+
+    // Double
+    BigDecimalBean beanDouble = deserialize("{'value': 1.1}", BigDecimalBean.class);
+    assertEquals(BigDecimal.valueOf(1.1), beanDouble.value);
+
+    // Boolean
+    try {
+      deserialize("{'value': true}", BigDecimalBean.class);
+      fail("Should throw");
+    } catch (RuntimeException e) { // ignore
+    }
+
+    // String
+    try {
+      deserialize("{'value': 'foo'}", BigDecimalBean.class);
+      fail("Should throw");
+    } catch (RuntimeException e) { // ignore
+    }
+  }
+
   @Test
   public void primitiveDeserializeFloat() {
     FloatBean beanFloat = deserialize("{'value': 1.1}", FloatBean.class);
@@ -1513,6 +1575,23 @@ public void serializeLongBean() {
     assertJson("{'value': 1234567890123}", serialize(bean));
   }
 
+  @Test
+  public void serializeBigDecimalBean() {
+    BigDecimalBean bean = new BigDecimalBean();
+    bean.value = BigDecimal.valueOf(1.1);
+    assertEquals(mapAnyType("value", "1.1"), serialize(bean));
+  }
+
+  @Test
+  public void bigDecimalRoundTrip() {
+    BigDecimal doubleMaxPlusOne = BigDecimal.valueOf(Double.MAX_VALUE).add(BigDecimal.ONE);
+    BigDecimalBean a = new BigDecimalBean();
+    a.value = doubleMaxPlusOne;
+    Map<String, Object> serialized = (Map<String, Object>) serialize(a);
+    BigDecimalBean b = convertToCustomClass(serialized, BigDecimalBean.class);
+    assertEquals(a, b);
+  }
+
   @Test
   public void serializeBooleanBean() {
     BooleanBean bean = new BooleanBean();
@@ -1827,7 +1906,7 @@ public void shortsCantBeSerialized() {
     final ShortBean bean = new ShortBean();
     bean.value = 1;
     assertExceptionContains(
-        "Numbers of type Short are not supported, please use an int, long, float or double (found in field 'value')",
+        "Numbers of type Short are not supported, please use an int, long, float, double or BigDecimal (found in field 'value')",
         new Runnable() {
           @Override
           public void run() {
@@ -1841,7 +1920,7 @@ public void bytesCantBeSerialized() {
     final ByteBean bean = new ByteBean();
     bean.value = 1;
     assertExceptionContains(
-        "Numbers of type Byte are not supported, please use an int, long, float or double (found in field 'value')",
+        "Numbers of type Byte are not supported, please use an int, long, float, double or BigDecimal (found in field 'value')",
         new Runnable() {
           @Override
           public void run() {
@@ -2478,7 +2557,7 @@ public void serializationFailureIncludesPath() {
     } catch (RuntimeException e) {
       assertEquals(
           "Could not serialize object. Numbers of type Short are not supported, please use an int, "
-              + "long, float or double (found in field 'value.inner.value.short')",
+              + "long, float, double or BigDecimal (found in field 'value.inner.value.short')",
           e.getMessage());
     }
   }