source: java2python/jackson-t/src/test/value/testcode/Value.java

package testcode;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;

import java.io.IOException;
import java.util.Objects;

import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
import com.fasterxml.jackson.databind.deser.std.StdDeserializer;

/*
 * This must be defined first, because in python the ValueDeserializer
 * must be able to refer to this. 
 * This deserializer also needs to refer to the Value class,
 * which is not yet defined. We therefore use 'Value'.
 */
/*#PY 
 * from pyson.Deserializer import Deserializer
 * from decimal import Decimal
 * 
 * class ValueDeserializer (Deserializer):
 *    def deserialize(self, data:object, clas: object) -> 'Value':
 *        if isinstance(data, float) or isinstance(data, int):
 *            return Value(data)
 *        if isinstance(data,str):
 *            return Value(data)
 *        raise ValueError("Expected number or double quoted string but found " + str(data)
 *                            + " of type " + str(type(data)))
 */
class ValueDeserializer extends StdDeserializer<Value> {
        public ValueDeserializer() {
                this(null);
        }

        public ValueDeserializer(Class<?> vc) {
                super(vc);
        }

        @Override
        public Value deserialize(JsonParser jp, DeserializationContext ctxt)
                        throws IOException, JsonProcessingException {
                String text = jp.getText();
                switch (jp.currentToken()) {
                case VALUE_NUMBER_FLOAT:
                case VALUE_NUMBER_INT:
                        return new Value(Float.parseFloat(text));
                case VALUE_STRING:
                        return new Value(text);
                default:
                        throw new IOException(
                                        "Expected number of double quoted string but found " + text
                                                        + " of type " + jp.currentToken());
                }

        }

}

@JsonDeserialize(using = ValueDeserializer.class)
public class Value {
        private final Object value;

        public Value(Object value) {
                this.value = value;
        }

        public Object getValue() {
                return value;
        }

        /** The test code for Value */
        public static void main(String[] args) throws JsonProcessingException {
                ObjectMapper jackson = new ObjectMapper();
                Value val = new Value(12f);
                System.out.println(jackson.writeValueAsString(val));
                assertEquals(val, jackson.readValue("12", Value.class));
                assertTrue(val.getValue() instanceof Float);
                val = new Value("hallo");
                System.out.println(jackson.writeValueAsString(val));
                assertEquals(val, jackson.readValue("\"hallo\"", Value.class));
        }

        @Override
        public int hashCode() {
                return Objects.hash(value);
        }

        @Override
        public boolean equals(Object obj) {
                if (this == obj)
                        return true;
                if (obj == null)
                        return false;
                if (getClass() != obj.getClass())
                        return false;
                Value other = (Value) obj;
                return Objects.equals(value, other.value);
        }

        @Override
        public String toString() {
                return "val:" + value;
        }
}