Part 4: custom serialiser on the real Jackson 3 StdSerializer signature

src/main/java/com/ankurm/jackson3/part4custom/E01MoneyValueSerializer.java

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+package com.ankurm.jackson3.part4custom;
+
+import tools.jackson.core.JsonGenerator;
+import tools.jackson.databind.SerializationContext;
+import tools.jackson.databind.ser.std.StdSerializer;
+
+import java.math.RoundingMode;
+
+/**
+ * Post: Custom Serialisers and Mix-ins — https://ankurm.com/jackson-custom-serializer-mixin/
+ * Section: "Writing a Custom Serialiser"
+ *
+ * Three Jackson 3 differences from the code in the post:
+ *   1. Package is tools.jackson.databind.ser.std, not com.fasterxml.jackson...
+ *   2. The third parameter is SerializationContext, not SerializerProvider.
+ *   3. There is no `throws IOException` — JacksonException is unchecked in Jackson 3.
+ *
+ * (StdSerializer still exists under its old name; only JsonSerializer was renamed,
+ *  to ValueSerializer. StdSerializer extends ValueSerializer.)
+ */
+public class E01MoneyValueSerializer extends StdSerializer<Money> {
+
+    public E01MoneyValueSerializer() {
+        super(Money.class);
+    }
+
+    @Override
+    public void serialize(Money moneyValue, JsonGenerator jsonGenerator, SerializationContext ctxt) {
+        jsonGenerator.writeStartObject();
+        // Write the amount rounded to 2 decimal places
+        jsonGenerator.writeNumberProperty("amount",
+                moneyValue.amount().setScale(2, RoundingMode.HALF_UP));
+        // Write the ISO currency code in uppercase
+        jsonGenerator.writeStringProperty("currency",
+                moneyValue.currencyCode().toUpperCase());
+        jsonGenerator.writeEndObject();
+    }
+}