866 - JacksonJsonBuffer - Overriding toString

java-client/src/main/java/co/elastic/clients/json/jackson/JacksonJsonBuffer.java

@@ -30,6 +30,7 @@
 import jakarta.json.stream.JsonParser;
 
 import java.io.IOException;
+import java.io.StringWriter;
 import java.lang.reflect.Type;
 
 class JacksonJsonBuffer implements JsonBuffer, JsonData {
@@ -99,4 +100,19 @@ public void serialize(JsonGenerator generator, JsonpMapper mapper) {
             }
         }
     }
+
+    /**
+     * Renders this buffer as a JSON string for debugger and logging convenience.
+     */
+    @Override
+    public String toString() {
+      StringWriter writer = new StringWriter();
+      try (JacksonJsonpGenerator generator = new JacksonJsonpGenerator(mapper.objectMapper().createGenerator(writer))) {
+        serialize(generator, mapper);
+        generator.close();
+        return writer.toString();
+      } catch (IOException e) {
+        return String.format("JacksonJsonBuffer: error rendering JSON: %s", e.getMessage());
+      }
+    }
 }

java-client/src/test/java/co/elastic/clients/json/jackson/JacksonJsonBufferTest.java

@@ -0,0 +1,71 @@
+/*
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you 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 co.elastic.clients.json.jackson;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.util.TokenBuffer;
+import org.apache.commons.lang3.StringUtils;
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+public class JacksonJsonBufferTest {
+
+  private JacksonJsonpMapper mapper() {
+    return new JacksonJsonpMapper(new ObjectMapper());
+  }
+
+  @Test
+  public void testToString_rendersJson() throws Exception {
+    ObjectMapper om = new ObjectMapper();
+    TokenBuffer buffer = new TokenBuffer(om, false);
+    buffer.writeStartObject();
+    buffer.writeStringField("foo", "bar");
+    buffer.writeNumberField("baz", 42);
+    buffer.writeEndObject();
+
+    JacksonJsonBuffer jsonBuffer = new JacksonJsonBuffer(buffer, mapper());
+    String json = jsonBuffer.toString();
+    assertTrue(json.contains("\"foo\":\"bar\""));
+    assertTrue(json.contains("\"baz\":42"));
+    assertTrue(json.startsWith("{") && json.endsWith("}"));
+  }
+
+  @Test
+  public void testToString_emptyBuffer() throws Exception {
+    ObjectMapper om = new ObjectMapper();
+    TokenBuffer buffer = new TokenBuffer(om, false);
+    JacksonJsonBuffer jsonBuffer = new JacksonJsonBuffer(buffer, mapper());
+    String json = jsonBuffer.toString();
+    assertEquals(StringUtils.EMPTY, json.trim());
+  }
+
+  @Test
+  public void testToString_invalidBuffer() throws Exception {
+    ObjectMapper om = new ObjectMapper();
+    TokenBuffer buffer = new TokenBuffer(om, false);
+    // Write some invalid JSON (start object but don't close)
+    buffer.writeStartObject();
+    JacksonJsonBuffer jsonBuffer = new JacksonJsonBuffer(buffer, mapper());
+    String json = jsonBuffer.toString();
+    // Should not throw, but may contain error or partial output
+    assertTrue(json.startsWith("{"));
+  }
+}