Merge pull request #900 from google/jw/array-and-parameterized-factories

Add static factories for array and parameterized type tokens.

gson/src/main/java/com/google/gson/reflect/TypeToken.java

@@ -302,4 +302,19 @@ public class TypeToken<T> {
   public static <T> TypeToken<T> get(Class<T> type) {
     return new TypeToken<T>(type);
   }
+
+  /**
+   * Gets type literal for the parameterized type represented by applying {@code typeArguments} to
+   * {@code rawType}.
+   */
+  public static TypeToken<?> getParameterized(Type rawType, Type... typeArguments) {
+    return new TypeToken<Object>($Gson$Types.newParameterizedTypeWithOwner(null, rawType, typeArguments));
+  }
+
+  /**
+   * Gets type literal for the array type whose elements are all instances of {@code componentType}.
+   */
+  public static TypeToken<?> getArray(Type componentType) {
+    return new TypeToken<Object>($Gson$Types.arrayOf(componentType));
+  }
 }

gson/src/test/java/com/google/gson/reflect/TypeTokenTest.java

@@ -19,6 +19,7 @@ package com.google.gson.reflect;
 import java.lang.reflect.Type;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Map;
 import java.util.RandomAccess;
 import java.util.Set;
 import junit.framework.TestCase;
@@ -79,4 +80,26 @@ public final class TypeTokenTest extends TestCase {
     // listOfSetOfUnknown = listOfSetOfString; // doesn't compile; must be false
     assertFalse(TypeToken.get(b).isAssignableFrom(a));
   }
+
+  public void testArrayFactory() {
+    TypeToken<?> expectedStringArray = new TypeToken<String[]>() {};
+    assertEquals(expectedStringArray, TypeToken.getArray(String.class));
+
+    TypeToken<?> expectedListOfStringArray = new TypeToken<List<String>[]>() {};
+    Type listOfString = new TypeToken<List<String>>() {}.getType();
+    assertEquals(expectedListOfStringArray, TypeToken.getArray(listOfString));
+  }
+
+  public void testParameterizedFactory() {
+    TypeToken<?> expectedListOfString = new TypeToken<List<String>>() {};
+    assertEquals(expectedListOfString, TypeToken.getParameterized(List.class, String.class));
+
+    TypeToken<?> expectedMapOfStringToString = new TypeToken<Map<String, String>>() {};
+    assertEquals(expectedMapOfStringToString, TypeToken.getParameterized(Map.class, String.class, String.class));
+
+    TypeToken<?> expectedListOfListOfListOfString = new TypeToken<List<List<List<String>>>>() {};
+    Type listOfString = TypeToken.getParameterized(List.class, String.class).getType();
+    Type listOfListOfString = TypeToken.getParameterized(List.class, listOfString).getType();
+    assertEquals(expectedListOfListOfListOfString, TypeToken.getParameterized(List.class, listOfListOfString));
+  }
 }