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src.bak/main/java/com/example/util/FirestoreTimestampDeserializer.java

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+/*
+* Copyright 2025 Google. This software is provided as-is, without warranty or representation for any use or purpose.
+* Your use of it is subject to your agreement with Google.
+*/
+
+package com.example.util;
+
+import com.fasterxml.jackson.core.JsonParser;
+import com.fasterxml.jackson.core.JsonToken;
+import com.fasterxml.jackson.databind.DeserializationContext;
+import com.fasterxml.jackson.databind.JsonDeserializer;
+import com.google.cloud.Timestamp;
+import java.io.IOException;
+import java.util.Map;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Custom Jackson Deserializer for com.google.cloud.Timestamp.
+ * Handles deserialization from embedded objects (direct Timestamp instances),
+ * ISO 8601 strings, and JSON objects with "seconds" and "nanos" fields.
+ */
+public class FirestoreTimestampDeserializer extends JsonDeserializer<Timestamp> {
+
+    private static final Logger logger = LoggerFactory.getLogger(FirestoreTimestampDeserializer.class);
+
+    @Override
+    public Timestamp deserialize(JsonParser p, DeserializationContext ctxt) throws IOException {
+        JsonToken token = p.getCurrentToken();
+
+        if (token == JsonToken.VALUE_EMBEDDED_OBJECT) {
+            // This is the ideal case when ObjectMapper.convertValue gets a direct Timestamp object
+            Object embedded = p.getEmbeddedObject();
+            if (embedded instanceof Timestamp) {
+                logger.debug("FirestoreTimestampDeserializer: Deserializing from embedded Timestamp object: {}", embedded);
+                return (Timestamp) embedded;
+            }
+        } else if (token == JsonToken.VALUE_STRING) {
+            // Handles cases where the timestamp is represented as an ISO 8601 string
+            String timestampString = p.getText();
+            try {
+                logger.debug("FirestoreTimestampDeserializer: Deserializing from String: {}", timestampString);
+                return Timestamp.parseTimestamp(timestampString);
+            } catch (IllegalArgumentException e) {
+                logger.error("FirestoreTimestampDeserializer: Failed to parse timestamp string: '{}'", timestampString, e);
+                throw new IOException("Failed to parse timestamp string: " + timestampString, e);
+            }
+        } else if (token == JsonToken.START_OBJECT) {
+            // This is crucial for handling the "Cannot deserialize ... from Object value (token JsonToken.START_OBJECT)" error.
+            // It assumes the object represents { "seconds": X, "nanos": Y }
+            logger.debug("FirestoreTimestampDeserializer: Deserializing from JSON object.");
+            
+            // Suppress the unchecked warning here, as we expect a Map<String, Number>
+            @SuppressWarnings("unchecked")
+            Map<String, Number> map = p.readValueAs(Map.class); 
+            
+            if (map != null && map.containsKey("seconds") && map.containsKey("nanos")) {
+                Number secondsNum = map.get("seconds");
+                Number nanosNum = map.get("nanos");
+                
+                if (secondsNum != null && nanosNum != null) {
+                    Long seconds = secondsNum.longValue();
+                    Integer nanos = nanosNum.intValue();
+                    return Timestamp.ofTimeSecondsAndNanos(seconds, nanos);
+                }
+            }
+            logger.error("FirestoreTimestampDeserializer: JSON object missing 'seconds' or 'nanos' fields, or fields are not numbers.");
+        }
+
+        // If none of the above formats match, log an error and delegate to default handling
+        logger.error("FirestoreTimestampDeserializer: Unexpected token type for Timestamp deserialization. Expected Embedded Object, String, or START_OBJECT. Got: {}", token);
+        // This will likely re-throw an error indicating inability to deserialize.
+        return (Timestamp) ctxt.handleUnexpectedToken(Timestamp.class, p);
+    }
+}