From 9be0fd9ecc91ba0eacf885faeec5f3d1d82fa99f Mon Sep 17 00:00:00 2001
From: Jesse Wilson <jesse@swank.ca>
Date: Sun, 18 Mar 2012 17:55:15 +0000
Subject: [PATCH] Make the BigDecimal and BigInteger type adapters
 user-overrideable.

---
 gson/src/main/java/com/google/gson/Gson.java  |  4 +--
 .../functional/DefaultTypeAdaptersTest.java   | 34 +++++++++++++++++++
 2 files changed, 36 insertions(+), 2 deletions(-)

diff --git a/gson/src/main/java/com/google/gson/Gson.java b/gson/src/main/java/com/google/gson/Gson.java
index 84dc68b8..6e58c512 100644
--- a/gson/src/main/java/com/google/gson/Gson.java
+++ b/gson/src/main/java/com/google/gson/Gson.java
@@ -211,8 +211,6 @@ public final class Gson {
     factories.add(TypeAdapters.CHARACTER_FACTORY);
     factories.add(TypeAdapters.STRING_BUILDER_FACTORY);
     factories.add(TypeAdapters.STRING_BUFFER_FACTORY);
-    factories.add(TypeAdapters.newFactory(BigDecimal.class, TypeAdapters.BIG_DECIMAL));
-    factories.add(TypeAdapters.newFactory(BigInteger.class, TypeAdapters.BIG_INTEGER));
     factories.add(TypeAdapters.JSON_ELEMENT_FACTORY);
     factories.add(ObjectTypeAdapter.FACTORY);
 
@@ -220,6 +218,8 @@ public final class Gson {
     factories.addAll(typeAdapterFactories);
 
     // built-in type adapters that can be overridden
+    factories.add(TypeAdapters.newFactory(BigDecimal.class, TypeAdapters.BIG_DECIMAL));
+    factories.add(TypeAdapters.newFactory(BigInteger.class, TypeAdapters.BIG_INTEGER));
     factories.add(new CollectionTypeAdapterFactory(constructorConstructor));
     factories.add(TypeAdapters.URL_FACTORY);
     factories.add(TypeAdapters.URI_FACTORY);
diff --git a/gson/src/test/java/com/google/gson/functional/DefaultTypeAdaptersTest.java b/gson/src/test/java/com/google/gson/functional/DefaultTypeAdaptersTest.java
index d7d3380a..2321f443 100644
--- a/gson/src/test/java/com/google/gson/functional/DefaultTypeAdaptersTest.java
+++ b/gson/src/test/java/com/google/gson/functional/DefaultTypeAdaptersTest.java
@@ -16,6 +16,7 @@
 package com.google.gson.functional;
 
 import java.io.IOException;
+import java.lang.reflect.Constructor;
 import java.lang.reflect.Type;
 import java.math.BigDecimal;
 import java.math.BigInteger;
@@ -266,6 +267,22 @@ public class DefaultTypeAdaptersTest extends TestCase {
     ClassWithBigInteger actual = gson.fromJson(json, ClassWithBigInteger.class);
     assertEquals(expected.value, actual.value);
   }
+  
+  public void testOverrideBigIntegerTypeAdapter() throws Exception {
+    gson = new GsonBuilder()
+        .registerTypeAdapter(BigInteger.class, new NumberAsStringAdapter(BigInteger.class))
+        .create();
+    assertEquals("\"123\"", gson.toJson(new BigInteger("123"), BigInteger.class));
+    assertEquals(new BigInteger("123"), gson.fromJson("\"123\"", BigInteger.class));
+  }
+
+  public void testOverrideBigDecimalTypeAdapter() throws Exception {
+    gson = new GsonBuilder()
+        .registerTypeAdapter(BigDecimal.class, new NumberAsStringAdapter(BigDecimal.class))
+        .create();
+    assertEquals("\"1.1\"", gson.toJson(new BigDecimal("1.1"), BigDecimal.class));
+    assertEquals(new BigDecimal("1.1"), gson.fromJson("\"1.1\"", BigDecimal.class));
+  }
 
   public void testSetSerialization() throws Exception {
     Gson gson = new Gson();
@@ -674,4 +691,21 @@ public class DefaultTypeAdaptersTest extends TestCase {
       }
     }
   }
+
+  static class NumberAsStringAdapter extends TypeAdapter<Number> {
+    private final Constructor<? extends Number> constructor;
+    NumberAsStringAdapter(Class<? extends Number> type) throws Exception {
+      this.constructor = type.getConstructor(String.class);
+    }
+    @Override public void write(JsonWriter out, Number value) throws IOException {
+      out.value(value.toString());
+    }
+    @Override public Number read(JsonReader in) throws IOException {
+      try {
+        return constructor.newInstance(in.nextString());
+      } catch (Exception e) {
+        throw new AssertionError(e);
+      }
+    }
+  }
 }