Add JsonReader.readJsonValue

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

@@ -17,6 +17,9 @@ package com.squareup.moshi;
 
 import java.io.Closeable;
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
 import okio.Buffer;
 import okio.BufferedSource;
 import okio.ByteString;
@@ -390,6 +393,57 @@ public abstract class JsonReader implements Closeable {
    */
   public abstract void skipValue() throws IOException;
 
+  /**
+   * Returns the value of the next token, consuming it. The result may be a string, number, boolean,
+   * null, map, or list, according to the JSON structure.
+   *
+   * @throws JsonDataException if the next token is not a literal value, if a JSON object has a
+   * duplicate key.
+   */
+  public final Object readJsonValue() throws IOException {
+    switch (peek()) {
+      case BEGIN_ARRAY:
+        List<Object> list = new ArrayList<>();
+        beginArray();
+        while (hasNext()) {
+          list.add(readJsonValue());
+        }
+        endArray();
+        return list;
+
+      case BEGIN_OBJECT:
+        Map<String, Object> map = new LinkedHashTreeMap<>();
+        beginObject();
+        while (hasNext()) {
+          String name = nextName();
+          Object value = readJsonValue();
+          Object replaced = map.put(name, value);
+          if (replaced != null) {
+            throw new JsonDataException("Map key '" + name + "' has multiple values at path "
+                + getPath() + ": " + replaced + " and " + value);
+          }
+        }
+        endObject();
+        return map;
+
+      case STRING:
+        return nextString();
+
+      case NUMBER:
+        return nextDouble();
+
+      case BOOLEAN:
+        return nextBoolean();
+
+      case NULL:
+        return nextNull();
+
+      default:
+        throw new IllegalStateException(
+            "Expected a value but was " + peek() + " at path " + getPath());
+    }
+  }
+
   /**
    * Returns a <a href="http://goessner.net/articles/JsonPath/">JsonPath</a> to
    * the current location in the JSON value.

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

@@ -18,11 +18,8 @@ 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.LinkedHashMap;
-import java.util.List;
 import java.util.Map;
 import java.util.Set;
 
@@ -272,47 +269,7 @@ final class StandardJsonAdapters {
     }
 
     @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()) {
-            String name = reader.nextName();
-            Object value = fromJson(reader);
-            Object replaced = map.put(name, value);
-            if (replaced != null) {
-              throw new JsonDataException("Map key '" + name + "' has multiple values at path "
-                  + reader.getPath() + ": " + replaced + " and " + value);
-            }
-          }
-          reader.endObject();
-          return map;
-
-        case STRING:
-          return reader.nextString();
-
-        case NUMBER:
-          return reader.nextDouble();
-
-        case BOOLEAN:
-          return reader.nextBoolean();
-
-        case NULL:
-          return reader.nextNull();
-
-        default:
-          throw new IllegalStateException("Expected a value but was " + reader.peek()
-              + " at path " + reader.getPath());
-      }
+      return reader.readJsonValue();
     }
 
     @Override public void toJson(JsonWriter writer, Object value) throws IOException {

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

@@ -17,6 +17,8 @@ package com.squareup.moshi;
 
 import java.io.EOFException;
 import java.io.IOException;
+import java.util.Arrays;
+import java.util.Collections;
 import java.util.List;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -912,4 +914,35 @@ public final class JsonReaderTest {
     assertThat(reader.nextString()).isEqualTo("a");
     reader.endArray();
   }
+
+  @Test public void readJsonValueInt() throws IOException {
+    JsonReader reader = newReader("1");
+    Object value = reader.readJsonValue();
+    assertThat(value).isEqualTo(1.0);
+  }
+
+  @Test public void readJsonValueMap() throws IOException {
+    JsonReader reader = newReader("{\"hello\": \"world\"}");
+    Object value = reader.readJsonValue();
+    assertThat(value).isEqualTo(Collections.singletonMap("hello", "world"));
+  }
+
+  @Test public void readJsonValueList() throws IOException {
+    JsonReader reader = newReader("[\"a\", \"b\"]");
+    Object value = reader.readJsonValue();
+    assertThat(value).isEqualTo(Arrays.asList("a", "b"));
+  }
+
+  @Test public void readJsonValueListMultipleTypes() throws IOException {
+    JsonReader reader = newReader("[\"a\", 5, false]");
+    Object value = reader.readJsonValue();
+    assertThat(value).isEqualTo(Arrays.asList("a", 5.0, false));
+  }
+
+  @Test public void readJsonValueNestedListInMap() throws IOException {
+    JsonReader reader = newReader("{\"pizzas\": [\"cheese\", \"pepperoni\"]}");
+    Object value = reader.readJsonValue();
+    assertThat(value).isEqualTo(
+        Collections.singletonMap("pizzas", Arrays.asList("cheese", "pepperoni")));
+  }
 }