Add an example for readJsonString and value(BufferedSource).

examples/src/main/java/com/squareup/moshi/recipes/ReadJsonString.java

@@ -0,0 +1,64 @@
+package com.squareup.moshi.recipes;
+
+import com.squareup.moshi.FromJson;
+import com.squareup.moshi.JsonAdapter;
+import com.squareup.moshi.JsonQualifier;
+import com.squareup.moshi.JsonReader;
+import com.squareup.moshi.JsonWriter;
+import com.squareup.moshi.Moshi;
+import com.squareup.moshi.ToJson;
+import java.io.IOException;
+import java.lang.annotation.Retention;
+import okio.Buffer;
+
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
+
+final class ReadJsonString {
+  @Retention(RUNTIME)
+  @JsonQualifier
+  public @interface JsonString {
+    Object ADAPTER = new Object() {
+      @FromJson @JsonString String fromJson(JsonReader reader) throws IOException {
+        return reader.readJsonString().utf8();
+      }
+
+      @ToJson void toJson(JsonWriter writer, @JsonString String value) throws IOException {
+        writer.value(new Buffer().writeUtf8(value));
+      }
+    };
+  }
+
+  static final class Location {
+    final String name;
+    final @JsonString String metadata;
+
+    Location(String name, String metadata) {
+      this.name = name;
+      this.metadata = metadata;
+    }
+  }
+
+  void run() throws IOException {
+    Moshi moshi = new Moshi.Builder()
+        .add(JsonString.ADAPTER)
+        .build();
+    JsonAdapter<Location> locationAdapter = moshi.adapter(Location.class);
+    String json = "{\n"
+        + "  \"name\": \"Niagara Falls\",\n"
+        + "  \"metadata\": {\n"
+        + "    \"latitude\": 43.0962,\n"
+        + "    \"longitude\": -79.0377\n"
+        + "  }\n"
+        + "}";
+    Location location = locationAdapter.fromJson(json);
+    System.out.println(location.metadata);
+    System.out.println(locationAdapter.toJson(new Location("Niagara Falls", "{\n"
+        + "    \"latitude\": 43.0962,\n"
+        + "    \"longitude\": -79.0377\n"
+        + "  }")));
+  }
+
+  public static void main(String[] args) throws IOException {
+    new ReadJsonString().run();
+  }
+}