Merge pull request #52 from square/jwilson_0613_object_adapter

Runtime type adapter.

moshi/src/main/java/com/squareup/moshi/AdapterMethodsFactory.java

@@ -24,9 +24,6 @@ import java.util.ArrayList;
 import java.util.List;
 import java.util.Set;
 
-// TODO: support @Nullable
-// TODO: path in JsonWriter.
-
 final class AdapterMethodsFactory implements JsonAdapter.Factory {
   private final List<AdapterMethod> toAdapters;
   private final List<AdapterMethod> fromAdapters;

moshi/src/main/java/com/squareup/moshi/JsonReader.java

@@ -1198,11 +1198,8 @@ public final class JsonReader implements Closeable {
             return c;
         }
       } else if (c == '#') {
-        /*
-         * Skip a # hash end-of-line comment. The JSON RFC doesn't
-         * specify this behaviour, but it's required to parse
-         * existing documents. See http://b/2571423.
-         */
+        // Skip a # hash end-of-line comment. The JSON RFC doesn't specify this behaviour, but it's
+        // required to parse existing documents. See http://b/2571423.
         checkLenient();
         skipToEndOfLine();
         p = 0;

moshi/src/main/java/com/squareup/moshi/Moshi.java

@@ -41,11 +41,11 @@ public final class Moshi {
     this.factories = Collections.unmodifiableList(factories);
   }
 
+  /** Returns a JSON adapter for {@code type}, creating it if necessary. */
   public <T> JsonAdapter<T> adapter(Type type) {
     return adapter(type, Util.NO_ANNOTATIONS);
   }
 
-  /** Returns a JSON adapter for {@code type}, creating it if necessary. */
   public <T> JsonAdapter<T> adapter(Class<T> type) {
     // TODO: cache created JSON adapters.
     return adapter(type, Util.NO_ANNOTATIONS);
@@ -60,10 +60,6 @@ public final class Moshi {
     return createAdapter(factories.indexOf(skipPast) + 1, type, annotations);
   }
 
-  public <T> JsonAdapter<T> nextAdapter(JsonAdapter.Factory skipPast, Type type) {
-    return nextAdapter(skipPast, type, Util.NO_ANNOTATIONS);
-  }
-
   @SuppressWarnings("unchecked") // Factories are required to return only matching JsonAdapters.
   private <T> JsonAdapter<T> createAdapter(
       int firstIndex, Type type, Set<? extends Annotation> annotations) {
@@ -125,7 +121,10 @@ public final class Moshi {
         @Override public JsonAdapter<?> create(
             Type targetType, Set<? extends Annotation> annotations, Moshi moshi) {
           if (!Util.typesMatch(type, targetType)) return null;
+
+          // TODO: check for an annotations exact match.
           if (!Util.isAnnotationPresent(annotations, annotation)) return null;
+
           return jsonAdapter;
         }
       });

moshi/src/main/java/com/squareup/moshi/StandardJsonAdapters.java

@@ -18,7 +18,11 @@ package com.squareup.moshi;
 import java.io.IOException;
 import java.lang.annotation.Annotation;
 import java.lang.reflect.Type;
+import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collection;
+import java.util.List;
+import java.util.Map;
 import java.util.Set;
 
 final class StandardJsonAdapters {
@@ -43,6 +47,7 @@ final class StandardJsonAdapters {
       if (type == Long.class) return LONG_JSON_ADAPTER.nullSafe();
       if (type == Short.class) return SHORT_JSON_ADAPTER.nullSafe();
       if (type == String.class) return STRING_JSON_ADAPTER.nullSafe();
+      if (type == Object.class) return new ObjectJsonAdapter(moshi).nullSafe();
 
       Class<?> rawType = Types.getRawType(type);
       if (rawType.isEnum()) {
@@ -189,4 +194,79 @@ final class StandardJsonAdapters {
       }
     };
   }
+
+  /**
+   * This adapter is used when the declared type is {@code java.lang.Object}. Typically the runtime
+   * type is something else, and when encoding JSON this delegates to the runtime type's adapter.
+   * For decoding (where there is no runtime type to inspect), this uses maps and lists.
+   *
+   * <p>This adapter needs a Moshi instance to look up the appropriate adapter for runtime types as
+   * they are encountered.
+   */
+  static final class ObjectJsonAdapter extends JsonAdapter<Object> {
+    private final Moshi moshi;
+
+    public ObjectJsonAdapter(Moshi moshi) {
+      this.moshi = moshi;
+    }
+
+    @Override public Object fromJson(JsonReader reader) throws IOException {
+      switch (reader.peek()) {
+        case BEGIN_ARRAY:
+          List<Object> list = new ArrayList<>();
+          reader.beginArray();
+          while (reader.hasNext()) {
+            list.add(fromJson(reader));
+          }
+          reader.endArray();
+          return list;
+
+        case BEGIN_OBJECT:
+          Map<String, Object> map = new LinkedHashTreeMap<>();
+          reader.beginObject();
+          while (reader.hasNext()) {
+            map.put(reader.nextName(), fromJson(reader));
+          }
+          reader.endObject();
+          return map;
+
+        case STRING:
+          return reader.nextString();
+
+        case NUMBER:
+          return reader.nextDouble();
+
+        case BOOLEAN:
+          return reader.nextBoolean();
+
+        default:
+          throw new IllegalStateException("Expected a value but was " + reader.peek()
+              + " at path " + reader.getPath());
+      }
+    }
+
+    @Override public void toJson(JsonWriter writer, Object value) throws IOException {
+      Class<?> valueClass = value.getClass();
+      if (valueClass == Object.class) {
+        // Don't recurse infinitely when the runtime type is also Object.class.
+        writer.beginObject();
+        writer.endObject();
+      } else {
+        moshi.adapter(toJsonType(valueClass), Util.NO_ANNOTATIONS).toJson(writer, value);
+      }
+    }
+
+    /**
+     * Returns the type to look up a type adapter for when writing {@code value} to JSON. Without
+     * this, attempts to emit standard types like `LinkedHashMap` would fail because Moshi doesn't
+     * provide built-in adapters for implementation types. It knows how to <strong>write</strong>
+     * those types, but lacks a mechanism to read them because it doesn't know how to find the
+     * appropriate constructor.
+     */
+    private Class<?> toJsonType(Class<?> valueClass) {
+      if (Map.class.isAssignableFrom(valueClass)) return Map.class;
+      if (Collection.class.isAssignableFrom(valueClass)) return Collection.class;
+      return valueClass;
+    }
+  }
 }

moshi/src/main/java/com/squareup/moshi/Types.java

@@ -48,18 +48,6 @@ final class Types {
     return new ParameterizedTypeImpl(null, rawType, typeArguments);
   }
 
-  /**
-   * Returns a new parameterized type, applying {@code typeArguments} to {@code rawType} and
-   * enclosed by {@code ownerType}.
-   */
-  public static ParameterizedType newParameterizedTypeWithOwner(
-      Type ownerType, Type rawType, Type... typeArguments) {
-    if (ownerType == null) {
-      throw new NullPointerException("ownerType");
-    }
-    return new ParameterizedTypeImpl(ownerType, rawType, typeArguments);
-  }
-
   /** Returns an array type whose elements are all instances of {@code componentType}. */
   public static GenericArrayType arrayOf(Type componentType) {
     return new GenericArrayTypeImpl(componentType);

moshi/src/test/java/com/squareup/moshi/CircularAdaptersTest.java

@@ -113,7 +113,7 @@ public final class CircularAdaptersTest {
         return null;
       }
 
-      final JsonAdapter<Node> delegate = moshi.nextAdapter(this, Node.class);
+      final JsonAdapter<Node> delegate = moshi.nextAdapter(this, Node.class, Util.NO_ANNOTATIONS);
 
       return new JsonAdapter<Node>() {
         @Override public void toJson(JsonWriter writer, Node value) throws IOException {

moshi/src/test/java/com/squareup/moshi/MoshiTest.java

@@ -35,7 +35,6 @@ import static org.assertj.core.api.Assertions.assertThat;
 import static org.junit.Assert.fail;
 
 public final class MoshiTest {
-
   @Test public void booleanAdapter() throws Exception {
     Moshi moshi = new Moshi.Builder().build();
     JsonAdapter<Boolean> adapter = moshi.adapter(boolean.class).lenient();
@@ -792,7 +791,8 @@ public final class MoshiTest {
       if (!type.equals(String.class)) return null;
       if (!Util.isAnnotationPresent(annotations, Uppercase.class)) return null;
 
-      final JsonAdapter<String> stringAdapter = moshi.nextAdapter(this, String.class);
+      final JsonAdapter<String> stringAdapter
+          = moshi.nextAdapter(this, String.class, Util.NO_ANNOTATIONS);
       return new JsonAdapter<String>() {
         @Override public String fromJson(JsonReader reader) throws IOException {
           String s = stringAdapter.fromJson(reader);

moshi/src/test/java/com/squareup/moshi/ObjectAdapterTest.java

@@ -0,0 +1,171 @@
+/*
+ * Copyright (C) 2015 Square, 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.squareup.moshi;
+
+import java.util.AbstractCollection;
+import java.util.AbstractList;
+import java.util.AbstractMap;
+import java.util.AbstractSet;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Date;
+import java.util.Iterator;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import org.junit.Ignore;
+import org.junit.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public final class ObjectAdapterTest {
+  @Test public void toJsonUsesRuntimeType() throws Exception {
+    Delivery delivery = new Delivery();
+    delivery.address = "1455 Market St.";
+    Pizza pizza = new Pizza();
+    pizza.diameter = 12;
+    pizza.extraCheese = true;
+    delivery.items = Arrays.asList(pizza, "Pepsi");
+
+    Moshi moshi = new Moshi.Builder().build();
+    JsonAdapter<Object> adapter = moshi.adapter(Object.class);
+    assertThat(adapter.toJson(delivery)).isEqualTo("{"
+        + "\"address\":\"1455 Market St.\","
+        + "\"items\":["
+        + "{\"diameter\":12,\"extraCheese\":true},"
+        + "\"Pepsi\""
+        + "]"
+        + "}");
+  }
+
+  @Test public void toJsonJavaLangObject() throws Exception {
+    Moshi moshi = new Moshi.Builder().build();
+    JsonAdapter<Object> adapter = moshi.adapter(Object.class);
+    assertThat(adapter.toJson(new Object())).isEqualTo("{}");
+  }
+
+  @Test public void fromJsonReturnsMapsAndLists() throws Exception {
+    Map<Object, Object> delivery = new LinkedHashMap<>();
+    delivery.put("address", "1455 Market St.");
+    Map<Object, Object> pizza = new LinkedHashMap<>();
+    pizza.put("diameter", 12d);
+    pizza.put("extraCheese", true);
+    delivery.put("items", Arrays.asList(pizza, "Pepsi"));
+
+    Moshi moshi = new Moshi.Builder().build();
+    JsonAdapter<Object> adapter = moshi.adapter(Object.class);
+    assertThat(adapter.fromJson("{"
+        + "\"address\":\"1455 Market St.\","
+        + "\"items\":["
+        + "{\"diameter\":12,\"extraCheese\":true},"
+        + "\"Pepsi\""
+        + "]"
+        + "}")).isEqualTo(delivery);
+  }
+
+  @Test public void fromJsonUsesDoublesForNumbers() throws Exception {
+    Moshi moshi = new Moshi.Builder().build();
+    JsonAdapter<Object> adapter = moshi.adapter(Object.class);
+    assertThat(adapter.fromJson("[0, 1]")).isEqualTo(Arrays.asList(0d, 1d));
+  }
+
+  @Test public void toJsonCoercesRuntimeTypeForCollections() throws Exception {
+    Collection<String> collection = new AbstractCollection<String>() {
+      @Override public Iterator<String> iterator() {
+        return Collections.singleton("A").iterator();
+      }
+      @Override public int size() {
+        return 1;
+      }
+    };
+
+    Moshi moshi = new Moshi.Builder().build();
+    JsonAdapter<Object> adapter = moshi.adapter(Object.class);
+    assertThat(adapter.toJson(collection)).isEqualTo("[\"A\"]");
+  }
+
+  @Test public void toJsonCoercesRuntimeTypeForLists() throws Exception {
+    List<String> list = new AbstractList<String>() {
+      @Override public String get(int i) {
+        return "A";
+      }
+
+      @Override public int size() {
+        return 1;
+      }
+    };
+
+    Moshi moshi = new Moshi.Builder().build();
+    JsonAdapter<Object> adapter = moshi.adapter(Object.class);
+    assertThat(adapter.toJson(list)).isEqualTo("[\"A\"]");
+  }
+
+  @Test public void toJsonCoercesRuntimeTypeForSets() throws Exception {
+    Set<String> set = new AbstractSet<String>() {
+      @Override public Iterator<String> iterator() {
+        return Collections.singleton("A").iterator();
+      }
+      @Override public int size() {
+        return 1;
+      }
+    };
+
+    Moshi moshi = new Moshi.Builder().build();
+    JsonAdapter<Object> adapter = moshi.adapter(Object.class);
+    assertThat(adapter.toJson(set)).isEqualTo("[\"A\"]");
+  }
+
+  @Ignore // We don't support raw maps, like Map<Object, Object>. (Even if the keys are strings!)
+  @Test public void toJsonCoercesRuntimeTypeForMaps() throws Exception {
+    Map<String, Boolean> map = new AbstractMap<String, Boolean>() {
+      @Override public Set<Entry<String, Boolean>> entrySet() {
+        return Collections.singletonMap("A", true).entrySet();
+      }
+    };
+
+    Moshi moshi = new Moshi.Builder().build();
+    JsonAdapter<Object> adapter = moshi.adapter(Object.class);
+    assertThat(adapter.toJson(map)).isEqualTo("{\"A\":true}");
+  }
+
+  @Test public void toJsonUsesTypeAdapters() throws Exception {
+    Object dateAdapter = new Object() {
+      @ToJson Long dateToJson(Date d) {
+        return d.getTime();
+      }
+      @FromJson Date dateFromJson(Long millis) {
+        return new Date(millis);
+      }
+    };
+    Moshi moshi = new Moshi.Builder()
+        .add(dateAdapter)
+        .build();
+    JsonAdapter<Object> adapter = moshi.adapter(Object.class);
+    assertThat(adapter.toJson(Arrays.asList(new Date(1), new Date(2)))).isEqualTo("[1,2]");
+  }
+
+  static class Delivery {
+    String address;
+    List<Object> items;
+  }
+
+  static class Pizza {
+    int diameter;
+    boolean extraCheese;
+  }
+}