Request Helidon Builder to allow adding annotations at builder level

[klustria]

Helidon Version: 4.2.x and higher

Enhancement Description

Looking for Helidon Builder to replace Lombok for generating builders. For example, a Lombok annotated code like:

   @Value
    @JsonDeserialize(builder = DemoWorkflowArguments.Builder.class)
    @Builder(builderClassName = "Builder")
    public static class DemoWorkflowArguments implements Loggable {

        @JsonProperty
        long size;
        @JsonProperty
        boolean encrypted;
        @JsonProperty
        int workflowId;

        @Override
        @JsonIgnore
        public Map<String, String> getDecorations() {
            HashMap<String, String> decorations = new HashMap<>();
            decorations.put(DefaultLogAndMetricsDecorator.CORRELATION_ID, "DemoWorkflowCorrelationId");
            return decorations;
        }

        @JsonPOJOBuilder(withPrefix = "")
        public static class Builder {
        }
    }

will generate this:

    @JsonDeserialize(
        builder = Builder.class
    )
    public static final class DemoWorkflowArguments implements Loggable {
        @JsonProperty
        private final long size;
        @JsonProperty
        private final boolean encrypted;
        @JsonProperty
        private final int workflowId;

        @JsonIgnore
        public Map<String, String> getDecorations() {
            HashMap<String, String> decorations = new HashMap();
            decorations.put("correlationId", "DemoWorkflowCorrelationId");
            return decorations;
        }

        @Generated
        DemoWorkflowArguments(long size, boolean encrypted, int workflowId) {
            this.size = size;
            this.encrypted = encrypted;
            this.workflowId = workflowId;
        }

        @Generated
        public static Builder builder() {
            return new Builder();
        }

        @Generated
        public long getSize() {
            return this.size;
        }

        @Generated
        public boolean isEncrypted() {
            return this.encrypted;
        }

        @Generated
        public int getWorkflowId() {
            return this.workflowId;
        }

        @Generated
        public boolean equals(Object o) {
            if (o == this) {
                return true;
            } else if (!(o instanceof DemoWorkflowArguments)) {
                return false;
            } else {
                DemoWorkflowArguments other = (DemoWorkflowArguments)o;
                if (this.getSize() != other.getSize()) {
                    return false;
                } else if (this.isEncrypted() != other.isEncrypted()) {
                    return false;
                } else {
                    return this.getWorkflowId() == other.getWorkflowId();
                }
            }
        }

        @Generated
        public int hashCode() {
            int PRIME = true;
            int result = 1;
            long $size = this.getSize();
            result = result * 59 + (int)($size >>> 32 ^ $size);
            result = result * 59 + (this.isEncrypted() ? 79 : 97);
            result = result * 59 + this.getWorkflowId();
            return result;
        }

        @Generated
        public String toString() {
            long var10000 = this.getSize();
            return "DemoWorkflow.DemoWorkflowArguments(size=" + var10000 + ", encrypted=" + this.isEncrypted() + ", workflowId=" + this.getWorkflowId() + ")";
        }

        @JsonPOJOBuilder(
            withPrefix = ""
        )
        public static class Builder {
            @Generated
            private long size;
            @Generated
            private boolean encrypted;
            @Generated
            private int workflowId;

            @Generated
            Builder() {
            }

            @JsonProperty
            @Generated
            public Builder size(long size) {
                this.size = size;
                return this;
            }

            @JsonProperty
            @Generated
            public Builder encrypted(boolean encrypted) {
                this.encrypted = encrypted;
                return this;
            }

            @JsonProperty
            @Generated
            public Builder workflowId(int workflowId) {
                this.workflowId = workflowId;
                return this;
            }

            @Generated
            public DemoWorkflowArguments build() {
                return new DemoWorkflowArguments(this.size, this.encrypted, this.workflowId);
            }

            @Generated
            public String toString() {
                return "DemoWorkflow.DemoWorkflowArguments.Builder(size=" + this.size + ", encrypted=" + this.encrypted + ", workflowId=" + this.workflowId + ")";
            }
        }
    }

Helidon Builder can do the following to emulate above result:

• Can switch to "java bean" style (io.helidon.builder.api.Prototype.Blueprint#beanStyle) to create getters and setters.
• Can add implementation of an interface (like implements Loggable above) and creates a default method on the interface to implement methods that need to be overriden.

Helidon is unable to:

• We do not have an ability to add annotations to builder. So this would work with serializing into JSON (using defaults for everything), but not for deserialization.

[tomas-langer]

I think we should add support for extensions of builder - i.e. add a JSON-B and Jackson extensions that would generate correct getters/setters as required.

Something like this:

@Prototype.Extension(JsonBindiing.class) // some class/annotation type that is part of the library
interface SomeBlueprint {
}

The extension would then get access to the type info/typed element infos of methods to read annotations and whatever else it needs to modify the generated prototype, builder, and possibly implementation.