http issue 110: HttpResponse.parseAs() accepts Void.class to ignore

https://code.google.com/p/google-http-java-client/issues/detail?id=110

https://codereview.appspot.com/8772044/

Author: Yaniv Inbar

google-http-client-test/src/main/java/com/google/api/client/testing/json/AbstractJsonFactoryTest.java

@@ -1366,4 +1366,32 @@ public void testJsonHttpContent_wrapped() throws Exception {
     content.writeTo(out);
     assertEquals(SIMPLE_WRAPPED, out.toString("UTF-8"));
   }
+
+  public static class V {
+    @Key
+    Void v;
+    @Key
+    String s;
+  }
+
+  public void testParse_void() throws Exception {
+    subtestParse_void(null);
+    subtestParse_void("\"a\"");
+    subtestParse_void("null");
+    subtestParse_void("true");
+    subtestParse_void("false");
+    subtestParse_void("123");
+    subtestParse_void("123.456");
+    subtestParse_void("[1]");
+    subtestParse_void("{\"v\":\"ignored\"}");
+  }
+
+  public void subtestParse_void(String value) throws Exception {
+    JsonFactory factory = newFactory();
+    String inputString = "{" + (value == null ? "" : "\"v\":" + value + ",") + "\"s\":\"svalue\"}";
+    V v = factory.fromString(inputString, V.class);
+    assertNull(v.v);
+    assertEquals("svalue", v.s);
+    assertNull(factory.fromString(inputString, Void.class));
+  }
 }

google-http-client/src/main/java/com/google/api/client/json/JsonParser.java

@@ -677,6 +677,11 @@ private final Object parseValue(Field fieldContext, Type valueType, ArrayList<Ty
       contextStringBuilder.append("]");
     }
     String contextString = contextStringBuilder.toString();
+    // Void means skip
+    if (valueClass == Void.class) {
+      skipChildren();
+      return null;
+    }
     // switch on token type
     switch (token) {
       case START_ARRAY:

google-http-client/src/main/java/com/google/api/client/util/Data.java

@@ -361,7 +361,9 @@ public static boolean isValueOfPrimitiveType(Object fieldValue) {
    * Parses the given string value based on the given primitive type.
    * <p>
    * Types are parsed as follows:
+   * </p>
    * <ul>
+   * <li>{@link Void}: null</li>
    * <li>{@code null} or is assignable from {@link String} (like {@link Object}): no parsing</li>
    * <li>{@code char} or {@link Character}: {@link String#charAt(int) String.charAt}(0) (requires
    * length to be exactly 1)</li>
@@ -381,6 +383,11 @@ public static boolean isValueOfPrimitiveType(Object fieldValue) {
    * Note that this may not be the right behavior for some use cases.
    * </p>
    *
+   * <p>
+   * Upgrade warning: in prior version 1.14 {@link Void} was not a legal input, but starting with
+   * version 1.15 it is now supported and returns {@code null}.
+   * </p>
+   *
    * @param type primitive type or {@code null} to parse as a string
    * @param stringValue string value to parse or {@code null} for {@code null} result
    * @return parsed object or {@code null} for {@code null} input
@@ -389,6 +396,9 @@ public static boolean isValueOfPrimitiveType(Object fieldValue) {
   public static Object parsePrimitiveValue(Type type, String stringValue) {
     Class<?> primitiveClass = type instanceof Class<?> ? (Class<?>) type : null;
     if (type == null || primitiveClass != null) {
+      if (primitiveClass == Void.class) {
+        return null;
+      }
       if (stringValue == null || primitiveClass == null
           || primitiveClass.isAssignableFrom(String.class)) {
         return stringValue;

google-http-client/src/main/java/com/google/api/client/xml/Xml.java

@@ -185,8 +185,8 @@ public boolean stopBeforeStartTag(String namespace, String localName) {
 
     /**
      * Returns whether to stop parsing when reaching the end tag of an XML element after it has been
-     * processed. Only called if the element is actually being processed. By default, returns {@code
-     * false}, but subclasses may override.
+     * processed. Only called if the element is actually being processed. By default, returns
+     * {@code false}, but subclasses may override.
      *
      * @param namespace XML element's namespace URI
      * @param localName XML element's local name
@@ -277,6 +277,7 @@ private static boolean parseElementInternal(XmlPullParser parser,
     Field field;
     ArrayValueMap arrayValueMap = new ArrayValueMap(destination);
     boolean isStopped = false;
+    // TODO(yanivi): support Void type as "ignore" element/attribute
     main: while (true) {
       int event = parser.next();
       switch (event) {
@@ -416,9 +417,8 @@ private static boolean parseElementInternal(XmlPullParser parser,
               // TODO(yanivi): some duplicate code here; isolate into reusable methods
               FieldInfo fieldInfo = FieldInfo.of(field);
               Object elementValue = null;
-              Type subFieldType =
-                  isArray ? Types.getArrayComponentType(fieldType) : Types.getIterableParameter(
-                      fieldType);
+              Type subFieldType = isArray
+                  ? Types.getArrayComponentType(fieldType) : Types.getIterableParameter(fieldType);
               Class<?> rawArrayComponentType =
                   Types.getRawArrayComponentType(context, subFieldType);
               subFieldType = Data.resolveWildcardTypeOrTypeVariable(context, subFieldType);
@@ -436,9 +436,9 @@ private static boolean parseElementInternal(XmlPullParser parser,
                 if (subFieldType != null) {
                   context.add(subFieldType);
                 }
-                Type subValueType =
-                    subFieldType != null && Map.class.isAssignableFrom(subFieldClass)
-                        ? Types.getMapValueParameter(subFieldType) : null;
+                Type subValueType = subFieldType != null
+                    && Map.class.isAssignableFrom(subFieldClass) ? Types.getMapValueParameter(
+                    subFieldType) : null;
                 subValueType = Data.resolveWildcardTypeOrTypeVariable(context, subValueType);
                 isStopped = parseElementInternal(parser,
                     context,

google-http-client/src/test/java/com/google/api/client/http/HttpHeadersTest.java

@@ -234,9 +234,8 @@ public static class SlugHeaders extends HttpHeaders {
   }
 
   public void testParseAge() throws Exception {
-    MockLowLevelHttpResponse httpResponse = new MockLowLevelHttpResponse()
-        .setHeaderNames(Arrays.asList("Age"))
-        .setHeaderValues(Arrays.asList("3456"));
+    MockLowLevelHttpResponse httpResponse = new MockLowLevelHttpResponse().setHeaderNames(
+        Arrays.asList("Age")).setHeaderValues(Arrays.asList("3456"));
 
     HttpHeaders httpHeaders = new HttpHeaders();
     httpHeaders.fromHttpResponse(httpResponse, null);
@@ -286,4 +285,20 @@ public void testFromHttpResponse_clearOldValue() throws Exception {
         .setHeaderValues(Arrays.asList("newvalue")), null);
     assertEquals(Arrays.asList("newvalue"), headers.get("Foo"));
   }
+
+  public static class V extends HttpHeaders {
+    @Key
+    Void v;
+    @Key
+    String s;
+  }
+
+  public void testFromHttpResponse_void(String value) throws Exception {
+    MockLowLevelHttpResponse httpResponse = new MockLowLevelHttpResponse().setHeaderNames(
+        Arrays.asList("v", "v", "s")).setHeaderValues(Arrays.asList("ignore", "ignore2", "svalue"));
+    V v = new V();
+    v.fromHttpResponse(httpResponse, null);
+    assertNull(v.v);
+    assertEquals("svalue", v.s);
+  }
 }

google-http-client/src/test/java/com/google/api/client/http/UrlEncodedParserTest.java

@@ -44,6 +44,10 @@ public UrlEncodedParserTest(String name) {
   }
 
   public static class Simple {
+
+    @Key
+    Void v;
+
     @Key
     String a;
 
@@ -74,8 +78,7 @@ public Simple() {
 
     @Override
     public String toString() {
-      return Objects
-          .toStringHelper(this)
+      return Objects.toStringHelper(this)
           .add("a", a)
           .add("b", b)
           .add("c", c)
@@ -84,7 +87,6 @@ public String toString() {
           .add("o", o)
           .toString();
     }
-
   }
 
   public static class Generic extends GenericData {
@@ -111,7 +113,8 @@ public Generic set(String fieldName, Object value) {
 
   public void testParse_simple() {
     Simple actual = new Simple();
-    UrlEncodedParser.parse("q=1&a=x&b=y&c=z&q=2&undeclared=0&o=object&r=a1&r=a2", actual);
+    UrlEncodedParser.parse(
+        "v=ignore&v=ignore2&q=1&a=x&b=y&c=z&q=2&undeclared=0&o=object&r=a1&r=a2", actual);
     Simple expected = new Simple();
     expected.a = "x";
     expected.b = "y";
@@ -120,6 +123,7 @@ public void testParse_simple() {
     expected.r = new String[] {"a1", "a2"};
     expected.o = new ArrayList<String>(Arrays.asList("object"));
     assertEquals(expected, actual);
+    assertNull(expected.v);
   }
 
   public void testParse_generic() {

google-http-client/src/test/java/com/google/api/client/util/DataTest.java

@@ -212,11 +212,11 @@ public void testParsePrimitiveValue() {
     assertEquals(new Double(Double.MAX_VALUE),
         Data.parsePrimitiveValue(double.class, String.valueOf(Double.MAX_VALUE)));
     BigInteger bigint = BigInteger.valueOf(Long.MAX_VALUE);
-    assertEquals(bigint,
-        Data.parsePrimitiveValue(BigInteger.class, String.valueOf(Long.MAX_VALUE)));
+    assertEquals(
+        bigint, Data.parsePrimitiveValue(BigInteger.class, String.valueOf(Long.MAX_VALUE)));
     BigDecimal bigdec = BigDecimal.valueOf(Double.MAX_VALUE);
-    assertEquals(bigdec,
-        Data.parsePrimitiveValue(BigDecimal.class, String.valueOf(Double.MAX_VALUE)));
+    assertEquals(
+        bigdec, Data.parsePrimitiveValue(BigDecimal.class, String.valueOf(Double.MAX_VALUE)));
     DateTime now = new DateTime(new Date());
     assertEquals(now, Data.parsePrimitiveValue(DateTime.class, now.toStringRfc3339()));
     try {
@@ -225,6 +225,7 @@ public void testParsePrimitiveValue() {
     } catch (IllegalArgumentException e) {
       // expected
     }
+    assertNull(Data.parsePrimitiveValue(Void.class, "abc"));
   }
 
   static class Resolve<X, T extends Number> {
@@ -278,8 +279,8 @@ public void testResolveWildcardTypeOrTypeVariable() throws Exception {
         Object.class, resolveWildcardTypeOrTypeVariable(new Object().getClass(), xTypeVar));
     assertEquals(Boolean.class, Types.getArrayComponentType(
         resolveWildcardTypeOrTypeVariable(new ArrayResolve().getClass(), xTypeVar)));
-    assertEquals(Collection.class,
-        Types.getRawClass((ParameterizedType) resolveWildcardTypeOrTypeVariable(
+    assertEquals(
+        Collection.class, Types.getRawClass((ParameterizedType) resolveWildcardTypeOrTypeVariable(
             new ParameterizedResolve().getClass(), xTypeVar)));
     assertEquals(Number.class, resolveWildcardTypeOrTypeVariable(
         new MedXResolve<Integer, Integer>().getClass(), xTypeVar));