1 files changed, 49 insertions, 0 deletions
diff --git a/extras/src/main/java/com/google/gson/interceptors/InterceptorFactory.java b/extras/src/main/java/com/google/gson/interceptors/InterceptorFactory.java
new file mode 100644
index 00000000..907fca3a
--- /dev/null
+++ b/extras/src/main/java/com/google/gson/interceptors/InterceptorFactory.java
@@ -0,0 +1,49 @@
+package com.google.gson.interceptors;
+
+import com.google.gson.Gson;
+import com.google.gson.TypeAdapter;
+import com.google.gson.TypeAdapterFactory;
+import com.google.gson.reflect.TypeToken;
+import com.google.gson.stream.JsonReader;
+import com.google.gson.stream.JsonWriter;
+import java.io.IOException;
+
+/**
+ * A type adapter factory that implements {@code @Intercept}.
+ */
+public final class InterceptorFactory implements TypeAdapterFactory {
+  public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type) {
+    Intercept intercept = type.getRawType().getAnnotation(Intercept.class);
+    if (intercept == null) {
+      return null;
+    }
+
+    TypeAdapter<T> delegate = gson.getDelegateAdapter(this, type);
+    return new InterceptorAdapter<T>(delegate, intercept);
+  }
+
+  static class InterceptorAdapter<T> extends TypeAdapter<T> {
+    private final TypeAdapter<T> delegate;
+    private final JsonPostDeserializer<T> postDeserializer;
+
+    @SuppressWarnings("unchecked") // ?
+    public InterceptorAdapter(TypeAdapter<T> delegate, Intercept intercept) {
+      try {
+        this.delegate = delegate;
+        this.postDeserializer = intercept.postDeserialize().newInstance();
+      } catch (Exception e) {
+        throw new RuntimeException(e);
+      }
+    }
+
+    @Override public void write(JsonWriter out, T value) throws IOException {
+      delegate.write(out, value);
+    }
+
+    @Override public T read(JsonReader in) throws IOException {
+      T result = delegate.read(in);
+      postDeserializer.postDeserialize(result);
+      return result;
+    }
+  }
+}