Add response type for JSON serialization using Jackson

1 files changed, 48 insertions, 0 deletions

diff --git a/container-core/src/main/java/com/yahoo/restapi/JacksonJsonResponse.java b/container-core/src/main/java/com/yahoo/restapi/JacksonJsonResponse.java
new file mode 100644
index 00000000000..d3b960651b0
--- /dev/null
+++ b/container-core/src/main/java/com/yahoo/restapi/JacksonJsonResponse.java
@@ -0,0 +1,48 @@
+// Copyright 2019 Oath Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.restapi;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.yahoo.container.jdisc.HttpResponse;
+import com.yahoo.log.LogLevel;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.util.logging.Logger;
+
+/**
+ * A JSON response using Jackson for serialization.
+ *
+ * @author bjorncs
+ */
+public class JacksonJsonResponse<T> extends HttpResponse {
+
+    private static final Logger log = Logger.getLogger(JacksonJsonResponse.class.getName());
+    private static final ObjectMapper defaultJsonMapper = new ObjectMapper();
+
+    private final ObjectMapper jsonMapper;
+    private final T entity;
+
+    public JacksonJsonResponse(int statusCode, T entity) {
+        this(statusCode, entity, defaultJsonMapper);
+    }
+
+    public JacksonJsonResponse(int statusCode, T entity, ObjectMapper jsonMapper) {
+        super(statusCode);
+        this.entity = entity;
+        this.jsonMapper = jsonMapper;
+    }
+
+    @Override
+    public void render(OutputStream outputStream) throws IOException {
+        if (log.isLoggable(LogLevel.DEBUG)) {
+            String json = jsonMapper.writeValueAsString(entity);
+            log.log(LogLevel.DEBUG, "Writing the following JSON to response output stream:\n" + json);
+            outputStream.write(json.getBytes());
+        } else {
+            jsonMapper.writeValue(outputStream, entity);
+        }
+    }
+
+    @Override public String getContentType() { return "application/json"; }
+    public T getEntity() { return entity; }
+}