Javadoc'ed + Cleanup of the api module (#267)

* Javadoc'ed more and more the api module
Cleanup the CloudEventRWException
More tests on the API module

Signed-off-by: Francesco Guardiani <francescoguard@gmail.com>

* Use parseTime

Signed-off-by: Francesco Guardiani <francescoguard@gmail.com>

* Better docs on the Extensions

Signed-off-by: Francesco Guardiani <francescoguard@gmail.com>

api/src/main/java/io/cloudevents/CloudEventData.java

@@ -19,11 +19,17 @@ package io.cloudevents;
 
 /**
  * Interface that defines a wrapper for CloudEvent data.
+ * <p>
+ * This interface can be overridden to include any type of data inside a {@link CloudEvent}, given it has a method to convert back to bytes.
  */
 public interface CloudEventData {
 
     /**
-     * @return this CloudEventData, represented as bytes. Note: this operation may be expensive, depending on the internal representation of data
+     * Returns the bytes representation of this data instance.
+     * <p>
+     * Note: depending on the implementation, this operation may be expensive.
+     *
+     * @return this data, represented as bytes.
      */
     byte[] toBytes();
 

api/src/main/java/io/cloudevents/CloudEventExtensions.java

@@ -23,7 +23,7 @@ import javax.annotation.ParametersAreNonnullByDefault;
 import java.util.Set;
 
 /**
- * The event extensions
+ * The event extensions.
  * <p>
  * Extensions values could be String/Number/Boolean
  */
@@ -34,7 +34,7 @@ public interface CloudEventExtensions {
      * Get the extension attribute named {@code extensionName}
      *
      * @param extensionName the extension name
-     * @return the extension value or null if this instance doesn't contain such extension
+     * @return the extension value in one of the valid types String/Number/Boolean or null if this instance doesn't contain such extension
      */
     @Nullable
     Object getExtension(String extensionName);

api/src/main/java/io/cloudevents/Extension.java

@@ -29,17 +29,17 @@ import java.util.Set;
 public interface Extension {
 
     /**
-     * Fill this materialized extension with values from a {@link CloudEventExtensions} implementation
+     * Fill this materialized extension with values from a {@link CloudEventExtensions} implementation.
      *
-     * @param extensions
+     * @param extensions the extensions where to read from
      */
     void readFrom(CloudEventExtensions extensions);
 
     /**
-     * Get the attribute of extension named {@code key}
+     * Get the attribute of extension named {@code key}.
      *
      * @param key the name of the extension attribute
-     * @return the extension value
+     * @return the extension value in one of the valid types String/Number/Boolean
      * @throws IllegalArgumentException if the key is unknown to this extension
      */
     @Nullable

api/src/main/java/io/cloudevents/SpecVersion.java

@@ -17,6 +17,8 @@
 
 package io.cloudevents;
 
+import io.cloudevents.rw.CloudEventRWException;
+
 import javax.annotation.ParametersAreNonnullByDefault;
 import java.util.*;
 import java.util.stream.Collectors;
@@ -62,7 +64,7 @@ public enum SpecVersion {
      *
      * @param sv String representing the spec version
      * @return The parsed spec version
-     * @throws IllegalArgumentException When the spec version string is unrecognized
+     * @throws CloudEventRWException When the spec version string is unrecognized
      */
     public static SpecVersion parse(String sv) {
         switch (sv) {
@@ -71,7 +73,7 @@ public enum SpecVersion {
             case "1.0":
                 return SpecVersion.V1;
             default:
-                throw new IllegalArgumentException("Unrecognized SpecVersion " + sv);
+                throw CloudEventRWException.newInvalidSpecVersion(sv);
         }
     }
 

api/src/main/java/io/cloudevents/rw/CloudEventAttributesWriter.java

@@ -32,18 +32,20 @@ public interface CloudEventAttributesWriter {
      * Set attribute with type {@link String}. This setter should not be invoked for specversion, because the built Visitor already
      * has the information through the {@link CloudEventWriterFactory}.
      *
-     * @param name
+     * @param name  name of the attribute
-     * @param value
+     * @param value value of the attribute
-     * @throws CloudEventRWException
+     * @return self
+     * @throws CloudEventRWException if anything goes wrong while writing this attribute.
      */
     CloudEventAttributesWriter withAttribute(String name, @Nullable String value) throws CloudEventRWException;
 
     /**
      * Set attribute with type {@link URI}.
      *
-     * @param name
+     * @param name name of the attribute
-     * @param value
+     * @param value value of the attribute
-     * @throws CloudEventRWException
+     * @throws CloudEventRWException if anything goes wrong while writing this attribute.
+     * @return self
      */
     default CloudEventAttributesWriter withAttribute(String name, @Nullable URI value) throws CloudEventRWException {
         return withAttribute(name, value == null ? null : value.toString());
@@ -52,12 +54,13 @@ public interface CloudEventAttributesWriter {
     /**
      * Set attribute with type {@link OffsetDateTime} attribute.
      *
-     * @param name
+     * @param name name of the attribute
-     * @param value
+     * @param value value of the attribute
-     * @throws CloudEventRWException
+     * @throws CloudEventRWException if anything goes wrong while writing this attribute.
+     * @return self
      */
     default CloudEventAttributesWriter withAttribute(String name, @Nullable OffsetDateTime value) throws CloudEventRWException {
-        return withAttribute(name, value == null ? null : Time.writeTime(value));
+        return withAttribute(name, value == null ? null : Time.writeTime(name, value));
     }
 
 }

api/src/main/java/io/cloudevents/rw/CloudEventExtensionsWriter.java

@@ -29,18 +29,20 @@ public interface CloudEventExtensionsWriter {
     /**
      * Set an extension with type {@link String}.
      *
-     * @param name
+     * @param name  name of the extension
-     * @param value
+     * @param value value of the extension
-     * @throws CloudEventRWException
+     * @return self
+     * @throws CloudEventRWException if anything goes wrong while writing this extension.
      */
     CloudEventExtensionsWriter withExtension(String name, @Nullable String value) throws CloudEventRWException;
 
     /**
      * Set attribute with type {@link URI}.
      *
-     * @param name
+     * @param name name of the extension
-     * @param value
+     * @param value value of the extension
-     * @throws CloudEventRWException
+     * @throws CloudEventRWException if anything goes wrong while writing this extension.
+     * @return self
      */
     default CloudEventExtensionsWriter withExtension(String name, @Nullable Number value) throws CloudEventRWException {
         return withExtension(name, value == null ? null : value.toString());
@@ -49,9 +51,10 @@ public interface CloudEventExtensionsWriter {
     /**
      * Set attribute with type {@link Boolean} attribute.
      *
-     * @param name
+     * @param name name of the extension
-     * @param value
+     * @param value value of the extension
-     * @throws CloudEventRWException
+     * @throws CloudEventRWException if anything goes wrong while writing this extension.
+     * @return self
      */
     default CloudEventExtensionsWriter withExtension(String name, @Nullable Boolean value) throws CloudEventRWException {
         return withExtension(name, value == null ? null : value.toString());

api/src/main/java/io/cloudevents/rw/CloudEventRWException.java

@@ -17,31 +17,64 @@
 
 package io.cloudevents.rw;
 
+/**
+ * This class is the exception Protocol Binding and Event Format implementers can use to signal errors while serializing/deserializing CloudEvent.
+ */
 public class CloudEventRWException extends RuntimeException {
 
+    /**
+     * The kind of error that happened while serializing/deserializing
+     */
     public enum CloudEventRWExceptionKind {
+        /**
+         * Spec version string is not recognized by this particular SDK version.
+         */
         INVALID_SPEC_VERSION,
+        /**
+         * The attribute name is not a valid/known context attribute.
+         */
         INVALID_ATTRIBUTE_NAME,
+        /**
+         * The extension name is not valid,
+         * because it doesn't follow the <a href="https://github.com/cloudevents/spec/blob/v1.0/spec.md#attribute-naming-convention">naming convention</a>
+         * enforced by the CloudEvents spec.
+         */
+        INVALID_EXTENSION_NAME,
+        /**
+         * The attribute/extension type is not valid.
+         */
         INVALID_ATTRIBUTE_TYPE,
+        /**
+         * The attribute/extension value is not valid.
+         */
         INVALID_ATTRIBUTE_VALUE,
-        INVALID_EXTENSION_TYPE,
+        /**
+         * The data type is not valid.
+         */
+        INVALID_DATA_TYPE,
+        /**
+         * Error while converting CloudEventData.
+         */
         DATA_CONVERSION,
+        /**
+         * Other error.
+         */
         OTHER
     }
 
     private final CloudEventRWExceptionKind kind;
 
-    public CloudEventRWException(CloudEventRWExceptionKind kind, Throwable cause) {
+    private CloudEventRWException(CloudEventRWExceptionKind kind, Throwable cause) {
         super(cause);
         this.kind = kind;
     }
 
-    public CloudEventRWException(CloudEventRWExceptionKind kind, String message) {
+    private CloudEventRWException(CloudEventRWExceptionKind kind, String message) {
         super(message);
         this.kind = kind;
     }
 
-    public CloudEventRWException(CloudEventRWExceptionKind kind, String message, Throwable cause) {
+    private CloudEventRWException(CloudEventRWExceptionKind kind, String message, Throwable cause) {
         super(message, cause);
         this.kind = kind;
     }
@@ -52,7 +85,7 @@ public class CloudEventRWException extends RuntimeException {
 
     public static CloudEventRWException newInvalidSpecVersion(String specVersion) {
         return new CloudEventRWException(
-            CloudEventRWExceptionKind.INVALID_ATTRIBUTE_TYPE,
+            CloudEventRWExceptionKind.INVALID_SPEC_VERSION,
             "Invalid specversion: " + specVersion
         );
     }
@@ -64,32 +97,45 @@ public class CloudEventRWException extends RuntimeException {
         );
     }
 
+    public static CloudEventRWException newInvalidExtensionName(String extensionName) {
+        return new CloudEventRWException(
+            CloudEventRWExceptionKind.INVALID_EXTENSION_NAME,
+            "Invalid extensions name: " + extensionName
+        );
+    }
+
     public static CloudEventRWException newInvalidAttributeType(String attributeName, Class<?> clazz) {
         return new CloudEventRWException(
             CloudEventRWExceptionKind.INVALID_ATTRIBUTE_TYPE,
-            "Invalid attribute type for \"" + attributeName + "\": " + clazz.getCanonicalName()
+            "Invalid attribute/extension type for \"" + attributeName + "\": " + clazz.getCanonicalName()
         );
     }
 
     public static CloudEventRWException newInvalidAttributeValue(String attributeName, Object value, Throwable cause) {
         return new CloudEventRWException(
             CloudEventRWExceptionKind.INVALID_ATTRIBUTE_VALUE,
-            "Invalid attribute value for \"" + attributeName + "\": " + value,
+            "Invalid attribute/extension value for \"" + attributeName + "\": " + value,
             cause
         );
     }
 
-    public static CloudEventRWException newInvalidExtensionType(String extensionName, Class<?> clazz) {
+    public static CloudEventRWException newInvalidDataType(String actual, String... allowed) {
+        String message;
+        if (allowed.length == 0) {
+            message = "Invalid data type: " + actual;
+        } else {
+            message = "Invalid data type: " + actual + ". Allowed: " + String.join(", ", allowed);
+        }
         return new CloudEventRWException(
-            CloudEventRWExceptionKind.INVALID_EXTENSION_TYPE,
+            CloudEventRWExceptionKind.INVALID_DATA_TYPE,
-            "Invalid extension type for \"" + extensionName + "\": " + clazz.getCanonicalName()
+            message
         );
     }
 
-    public static CloudEventRWException newDataConversion(Throwable cause, String to) {
+    public static CloudEventRWException newDataConversion(Throwable cause, String from, String to) {
         return new CloudEventRWException(
             CloudEventRWExceptionKind.DATA_CONVERSION,
-            "Error while trying to convert data to " + to,
+            "Error while trying to convert data from " + from + " to " + to,
             cause
         );
     }

api/src/main/java/io/cloudevents/rw/CloudEventReader.java

@@ -33,7 +33,7 @@ public interface CloudEventReader {
      * Visit self using the provided visitor factory
      *
      * @param writerFactory a factory that generates a visitor starting from the SpecVersion of the event
-     * @throws CloudEventRWException if something went wrong during the visit.
+     * @throws CloudEventRWException if something went wrong during the read.
      */
     default <V extends CloudEventWriter<R>, R> R read(CloudEventWriterFactory<V, R> writerFactory) throws CloudEventRWException {
         return read(writerFactory, null);

api/src/main/java/io/cloudevents/rw/CloudEventWriter.java

@@ -31,6 +31,7 @@ public interface CloudEventWriter<R> extends CloudEventAttributesWriter, CloudEv
      * End the visit with a data field
      *
      * @return an eventual return value
+     * @throws CloudEventRWException if the message writer cannot be ended.
      */
     R end(CloudEventData data) throws CloudEventRWException;
 
@@ -38,7 +39,8 @@ public interface CloudEventWriter<R> extends CloudEventAttributesWriter, CloudEv
      * End the visit
      *
      * @return an eventual return value
+     * @throws CloudEventRWException if the message writer cannot be ended.
      */
-    R end();
+    R end() throws CloudEventRWException;
 
 }

api/src/main/java/io/cloudevents/rw/CloudEventWriterFactory.java

@@ -25,8 +25,9 @@ public interface CloudEventWriterFactory<V extends CloudEventWriter<R>, R> {
     /**
      * Create a {@link CloudEventWriter} starting from the provided {@link SpecVersion}
      *
-     * @param version
+     * @param version the spec version to create the writer
-     * @return
+     * @return the new writer
+     * @throws CloudEventRWException if the spec version is invalid or the writer cannot be instantiated.
      */
-    V create(SpecVersion version);
+    V create(SpecVersion version) throws CloudEventRWException;
 }

api/src/main/java/io/cloudevents/types/Time.java

@@ -17,6 +17,9 @@
 
 package io.cloudevents.types;
 
+import io.cloudevents.rw.CloudEventRWException;
+
+import java.time.DateTimeException;
 import java.time.OffsetDateTime;
 import java.time.format.DateTimeParseException;
 
@@ -31,16 +34,56 @@ public final class Time {
     }
 
     /**
-     * Parse a {@link String} RFC3339 compliant as {@link OffsetDateTime}
+     * Parse a {@link String} RFC3339 compliant as {@link OffsetDateTime}.
+     *
+     * @param time the value to parse as time
+     * @return the parsed {@link OffsetDateTime}
+     * @throws DateTimeParseException if something went wrong when parsing the provided time.
      */
     public static OffsetDateTime parseTime(String time) throws DateTimeParseException {
         return OffsetDateTime.parse(time);
     }
 
     /**
-     * Convert a {@link OffsetDateTime} to a RFC3339 compliant {@link String}
+     * Parse an attribute/extension with RFC3339 compliant {@link String} value as {@link OffsetDateTime}.
+     *
+     * @param attributeName the attribute/extension name
+     * @param time          the value to parse as time
+     * @return the parsed {@link OffsetDateTime}
+     * @throws CloudEventRWException if something went wrong when parsing the attribute/extension.
      */
-    public static String writeTime(OffsetDateTime time) throws DateTimeParseException {
+    public static OffsetDateTime parseTime(String attributeName, String time) throws CloudEventRWException {
+        try {
+            return parseTime(time);
+        } catch (DateTimeParseException e) {
+            throw CloudEventRWException.newInvalidAttributeValue(attributeName, time, e);
+        }
+    }
+
+    /**
+     * Convert a {@link OffsetDateTime} to a RFC3339 compliant {@link String}.
+     *
+     * @param time the time to write as {@link String}
+     * @return the serialized time
+     * @throws DateTimeException if something went wrong when serializing the provided time.
+     */
+    public static String writeTime(OffsetDateTime time) throws DateTimeException {
         return ISO_OFFSET_DATE_TIME.format(time);
     }
+
+    /**
+     * Convert an attribute/extension {@link OffsetDateTime} to a RFC3339 compliant {@link String}.
+     *
+     * @param attributeName the attribute/extension name
+     * @param time          the time to write as {@link String}
+     * @return the serialized time
+     * @throws CloudEventRWException if something went wrong when serializing the attribute/extension.
+     */
+    public static String writeTime(String attributeName, OffsetDateTime time) throws DateTimeException {
+        try {
+            return writeTime(time);
+        } catch (DateTimeParseException e) {
+            throw CloudEventRWException.newInvalidAttributeValue(attributeName, time, e);
+        }
+    }
 }

api/src/test/java/io/cloudevents/SpecVersionTest.java

@@ -0,0 +1,21 @@
+package io.cloudevents;
+
+import io.cloudevents.rw.CloudEventRWException;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatCode;
+import static org.junit.jupiter.api.Assertions.assertAll;
+
+class SpecVersionTest {
+
+    @Test
+    void parse() {
+        assertAll(
+            () -> assertThat(SpecVersion.parse("1.0")).isEqualTo(SpecVersion.V1),
+            () -> assertThat(SpecVersion.parse("0.3")).isEqualTo(SpecVersion.V03),
+            () -> assertThatCode(() -> SpecVersion.parse("9000.1"))
+                .hasMessage(CloudEventRWException.newInvalidSpecVersion("9000.1").getMessage())
+        );
+    }
+}

api/src/test/java/io/cloudevents/types/TimeTest.java

@@ -17,6 +17,7 @@
 package io.cloudevents.types;
 
 
+import io.cloudevents.rw.CloudEventRWException;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
@@ -28,6 +29,7 @@ import java.time.ZoneOffset;
 import java.util.stream.Stream;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatCode;
 
 public class TimeTest {
 
@@ -44,6 +46,13 @@ public class TimeTest {
             .isEqualTo("1937-01-01T12:00:27.87Z");
     }
 
+    @Test
+    void testParseTimeException() {
+        assertThatCode(() -> Time.parseTime("time", "01-01T12:20:27.87+00:20"))
+            .isInstanceOf(CloudEventRWException.class)
+            .hasMessage(CloudEventRWException.newInvalidAttributeValue("time", "01-01T12:20:27.87+00:20", null).getMessage());
+    }
+
     @Test
     void testSerializeDateOffset() {
         assertThat(Time.writeTime(OffsetDateTime.of(

core/src/main/java/io/cloudevents/core/impl/BaseCloudEvent.java

@@ -62,15 +62,15 @@ public abstract class BaseCloudEvent implements CloudEvent, CloudEventReader, Cl
         return visitor.end();
     }
 
-    public void readExtensions(CloudEventExtensionsWriter visitor) throws CloudEventRWException {
+    public void readExtensions(CloudEventExtensionsWriter writer) throws CloudEventRWException {
         // TODO to be improved
         for (Map.Entry<String, Object> entry : this.extensions.entrySet()) {
             if (entry.getValue() instanceof String) {
-                visitor.withExtension(entry.getKey(), (String) entry.getValue());
+                writer.withExtension(entry.getKey(), (String) entry.getValue());
             } else if (entry.getValue() instanceof Number) {
-                visitor.withExtension(entry.getKey(), (Number) entry.getValue());
+                writer.withExtension(entry.getKey(), (Number) entry.getValue());
             } else if (entry.getValue() instanceof Boolean) {
-                visitor.withExtension(entry.getKey(), (Boolean) entry.getValue());
+                writer.withExtension(entry.getKey(), (Boolean) entry.getValue());
             } else {
                 // This should never happen because we build that map only through our builders
                 throw new IllegalStateException("Illegal value inside extensions map: " + entry);

core/src/main/java/io/cloudevents/core/impl/CloudEventReaderAdapter.java

@@ -61,15 +61,15 @@ public class CloudEventReaderAdapter implements CloudEventReader, CloudEventCont
     }
 
     @Override
-    public void readExtensions(CloudEventExtensionsWriter visitor) throws RuntimeException {
+    public void readExtensions(CloudEventExtensionsWriter writer) throws RuntimeException {
         for (String key : event.getExtensionNames()) {
             Object value = event.getExtension(key);
             if (value instanceof String) {
-                visitor.withExtension(key, (String) value);
+                writer.withExtension(key, (String) value);
             } else if (value instanceof Number) {
-                visitor.withExtension(key, (Number) value);
+                writer.withExtension(key, (Number) value);
             } else if (value instanceof Boolean) {
-                visitor.withExtension(key, (Boolean) value);
+                writer.withExtension(key, (Boolean) value);
             } else {
                 // This should never happen because we build that map only through our builders
                 throw new IllegalStateException("Illegal value inside extensions map: " + key + " " + value);

core/src/main/java/io/cloudevents/core/v03/CloudEventBuilder.java

@@ -25,7 +25,6 @@ import io.cloudevents.types.Time;
 import java.net.URI;
 import java.net.URISyntaxException;
 import java.time.OffsetDateTime;
-import java.time.format.DateTimeParseException;
 
 /**
  * CloudEvent V0.3 builder.
@@ -167,11 +166,7 @@ public final class CloudEventBuilder extends BaseCloudEventBuilder<CloudEventBui
                 withSubject(value);
                 return this;
             case "time":
-                try {
+                withTime(Time.parseTime("time", value));
-                    withTime(Time.parseTime(value));
-                } catch (DateTimeParseException e) {
-                    throw CloudEventRWException.newInvalidAttributeValue("time", value, e);
-                }
                 return this;
         }
         throw CloudEventRWException.newInvalidAttributeName(name);

core/src/main/java/io/cloudevents/core/v03/V1ToV03AttributesConverter.java

@@ -24,7 +24,6 @@ import io.cloudevents.types.Time;
 import java.net.URI;
 import java.net.URISyntaxException;
 import java.time.OffsetDateTime;
-import java.time.format.DateTimeParseException;
 
 class V1ToV03AttributesConverter implements CloudEventAttributesWriter {
 
@@ -64,11 +63,7 @@ class V1ToV03AttributesConverter implements CloudEventAttributesWriter {
                 builder.withSubject(value);
                 return this;
             case "time":
-                try {
+                builder.withTime(Time.parseTime("time", value));
-                    builder.withTime(Time.parseTime(value));
-                } catch (DateTimeParseException e) {
-                    throw CloudEventRWException.newInvalidAttributeValue("time", value, e);
-                }
                 return this;
         }
         throw CloudEventRWException.newInvalidAttributeName(name);

core/src/main/java/io/cloudevents/core/v1/CloudEventBuilder.java

@@ -27,7 +27,6 @@ import io.cloudevents.types.Time;
 import java.net.URI;
 import java.net.URISyntaxException;
 import java.time.OffsetDateTime;
-import java.time.format.DateTimeParseException;
 
 /**
  * CloudEvent V1.0 builder.
@@ -161,11 +160,7 @@ public final class CloudEventBuilder extends BaseCloudEventBuilder<CloudEventBui
                 withSubject(value);
                 return this;
             case "time":
-                try {
+                withTime(Time.parseTime("time", value));
-                    withTime(Time.parseTime(value));
-                } catch (DateTimeParseException e) {
-                    throw CloudEventRWException.newInvalidAttributeValue("time", value, e);
-                }
                 return this;
         }
         throw CloudEventRWException.newInvalidAttributeName(name);

core/src/main/java/io/cloudevents/core/v1/V03ToV1AttributesConverter.java

@@ -24,7 +24,6 @@ import io.cloudevents.types.Time;
 import java.net.URI;
 import java.net.URISyntaxException;
 import java.time.OffsetDateTime;
-import java.time.format.DateTimeParseException;
 
 class V03ToV1AttributesConverter implements CloudEventAttributesWriter {
 
@@ -64,11 +63,7 @@ class V03ToV1AttributesConverter implements CloudEventAttributesWriter {
                 builder.withSubject(value);
                 return this;
             case "time":
-                try {
+                builder.withTime(Time.parseTime("time", value));
-                    builder.withTime(Time.parseTime(value));
-                } catch (DateTimeParseException e) {
-                    throw CloudEventRWException.newInvalidAttributeValue("time", value, e);
-                }
                 return this;
         }
         throw CloudEventRWException.newInvalidAttributeName(name);

core/src/test/java/io/cloudevents/core/mock/MockBinaryMessageWriter.java

@@ -95,14 +95,14 @@ public class MockBinaryMessageWriter extends BaseBinaryMessageReader implements
     }
 
     @Override
-    public void readExtensions(CloudEventExtensionsWriter visitor) throws CloudEventRWException, IllegalStateException {
+    public void readExtensions(CloudEventExtensionsWriter writer) throws CloudEventRWException, IllegalStateException {
         for (Map.Entry<String, Object> entry : this.extensions.entrySet()) {
             if (entry.getValue() instanceof String) {
-                visitor.withExtension(entry.getKey(), (String) entry.getValue());
+                writer.withExtension(entry.getKey(), (String) entry.getValue());
             } else if (entry.getValue() instanceof Number) {
-                visitor.withExtension(entry.getKey(), (Number) entry.getValue());
+                writer.withExtension(entry.getKey(), (Number) entry.getValue());
             } else if (entry.getValue() instanceof Boolean) {
-                visitor.withExtension(entry.getKey(), (Boolean) entry.getValue());
+                writer.withExtension(entry.getKey(), (Boolean) entry.getValue());
             } else {
                 // This should never happen because we build that map only through our builders
                 throw new IllegalStateException("Illegal value inside extensions map: " + entry);

formats/json-jackson/src/main/java/io/cloudevents/jackson/PojoCloudEventData.java

@@ -33,7 +33,7 @@ public class PojoCloudEventData<T> implements CloudEventData {
             try {
                 this.memoizedValue = mapper.writeValueAsBytes(value);
             } catch (JsonProcessingException e) {
-                throw CloudEventRWException.newDataConversion(e, "byte[]");
+                throw CloudEventRWException.newDataConversion(e, value.getClass().toString(), "byte[]");
             }
         }
         return this.memoizedValue;

formats/json-jackson/src/main/java/io/cloudevents/jackson/PojoCloudEventDataMapper.java

@@ -28,7 +28,7 @@ public class PojoCloudEventDataMapper<T> implements CloudEventDataMapper<PojoClo
             try {
                 value = this.mapper.convertValue(node, target);
             } catch (Exception e) {
-                throw CloudEventRWException.newDataConversion(e, target.getTypeName());
+                throw CloudEventRWException.newDataConversion(e, JsonNode.class.toString(), target.getTypeName());
             }
             return new PojoCloudEventData<>(mapper, value);
         }
@@ -39,7 +39,7 @@ public class PojoCloudEventDataMapper<T> implements CloudEventDataMapper<PojoClo
         try {
             value = this.mapper.readValue(bytes, this.target);
         } catch (Exception e) {
-            throw CloudEventRWException.newDataConversion(e, target.getTypeName());
+            throw CloudEventRWException.newDataConversion(e, byte[].class.toString(), target.getTypeName());
         }
         return new PojoCloudEventData<>(mapper, value, bytes);
     }