Parsing numbers lazily as a performance enhancement.

This avoids needing to parse number if the equivalent object field doesn't exist.
It also avoids the performance penalty of trying to parse it eagerly as a big decimal, float etc.

gson/src/main/java/com/google/gson/JsonPrimitive.java

@@ -31,6 +31,7 @@ import java.math.BigInteger;
  * @author Joel Leitch
  */
 public final class JsonPrimitive extends JsonElement {
+
   private static final Class<?>[] PRIMITIVE_TYPES = { int.class, long.class, short.class,
       float.class, double.class, byte.class, boolean.class, char.class, Integer.class, Long.class,
       Short.class, Float.class, Double.class, Byte.class, Boolean.class, Character.class };
@@ -154,24 +155,7 @@ public final class JsonPrimitive extends JsonElement {
    */
   @Override
   public Number getAsNumber() {
-    return value instanceof String ? stringToNumber((String) value) : (Number) value;
-  }
-
-  static Number stringToNumber(String value) {
-    try {
-      long longValue = Long.parseLong(value);
-      if (longValue >= Integer.MIN_VALUE && longValue <= Integer.MAX_VALUE) {
-        return (int) longValue;
-      }
-      return longValue;
-    } catch (NumberFormatException ignored) {
-    }
-
-    try {
-      return new BigDecimal(value);
-    } catch (NumberFormatException ignored) {
-      return Double.parseDouble(value); // probably NaN, -Infinity or Infinity
-    }
+    return value instanceof String ? new LazilyParsedNumber((String) value) : (Number) value;
   }
 
   /**

gson/src/main/java/com/google/gson/LazilyParsedNumber.java

@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2011 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.gson;
+
+/**
+ * This class holds a number value that is lazily converted to a specific number type
+ *
+ * @author Inderjeet Singh
+ */
+@SuppressWarnings("serial")
+final class LazilyParsedNumber extends Number {
+  private final String value;
+
+  LazilyParsedNumber(String value) {
+    this.value = value;
+  }
+
+  @Override
+  public int intValue() {
+    return Integer.parseInt(value);
+  }
+
+  @Override
+  public long longValue() {
+    return Long.parseLong(value);
+  }
+
+  @Override
+  public float floatValue() {
+    return Float.parseFloat(value);
+  }
+
+  @Override
+  public double doubleValue() {
+    return Double.parseDouble(value);
+  }
+
+  @Override
+  public String toString() {
+    return value;
+  }
+}

gson/src/main/java/com/google/gson/Streams.java

@@ -62,7 +62,7 @@ final class Streams {
       return new JsonPrimitive(reader.nextString());
     case NUMBER:
       String number = reader.nextString();
-      return new JsonPrimitive(JsonPrimitive.stringToNumber(number));
+      return new JsonPrimitive(new LazilyParsedNumber(number));
     case BOOLEAN:
       return new JsonPrimitive(reader.nextBoolean());
     case NULL:

gson/src/test/java/com/google/gson/functional/ArrayTest.java

@@ -206,12 +206,13 @@ public class ArrayTest extends TestCase {
   }
 
   public void testArrayOfPrimitivesAsObjectsDeserialization() throws Exception {
-    String json = "[1,'abc',0.3,5]";
+    String json = "[1,'abc',0.3,1.1,5]";
     Object[] objs = gson.fromJson(json, Object[].class);
-    assertEquals(1, objs[0]);
+    assertEquals(1, ((Number)objs[0]).intValue());
     assertEquals("abc", objs[1]);
-    assertEquals(new BigDecimal("0.3"), objs[2]);
-    assertEquals(5, objs[3]);
+    assertEquals(0.3, ((Number)objs[2]).doubleValue());
+    assertEquals(new BigDecimal("1.1"), new BigDecimal(objs[3].toString()));
+    assertEquals(5, ((Number)objs[4]).shortValue());
   }
 
   public void testArrayOfObjectsWithoutTypeInfoDeserialization() throws Exception {

gson/src/test/java/com/google/gson/functional/ParameterizedTypesTest.java

@@ -127,7 +127,7 @@ public class ParameterizedTypesTest extends TestCase {
     MyParameterizedType<Integer> src = new MyParameterizedType<Integer>(10);
     String json = MyParameterizedTypeAdapter.<Integer>getExpectedJson(src);
     MyParameterizedType<Integer> intTarget = gson.fromJson(json, ptIntegerType);
-    assertEquals(10, (int) intTarget.value);
+    assertEquals(10, ((Number)intTarget.value).intValue());
 
     MyParameterizedType<String> srcStr = new MyParameterizedType<String>("abc");
     json = MyParameterizedTypeAdapter.<String>getExpectedJson(srcStr);