source: dialogmanager/src/test/java/JacksonTest.java@ 429

import static org.junit.Assert.assertEquals;

import org.junit.Test;

import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.JsonAutoDetect.Visibility;
import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonSubTypes;
import com.fasterxml.jackson.annotation.JsonTypeInfo;
import com.fasterxml.jackson.annotation.JsonValue;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;

/**
 * There are serious issues with some jackson versions. We need to check what we
 * are up to to ensure our code works properly.
 *
 */
public class JacksonTest {
        final ObjectMapper jackson = new ObjectMapper();
        final N n = new N();

        @Test
        public void testN() throws JsonProcessingException {
                doTest(new N());
        }

        @Test
        public void testYN() throws JsonProcessingException {
                doTest(new Y(n));
        }

        @Test
        public void testYYN() throws JsonProcessingException {
                doTest(new Y(new Y(n)));
        }

        @Test
        public void testZYN() throws JsonProcessingException {
                doTest(new Z(new Y(n)));
        }

        @Test
        public void testZN() throws JsonProcessingException {
                doTest(new Z(n));
        }

        private void doTest(X val) throws JsonProcessingException {
                System.out.println("testing " + val);
                String str = jackson.writeValueAsString(val);
                System.out.println("To json: " + str);
                X obj = jackson.readValue(str, X.class);
                System.out.println("reparsed: " + obj);

                assertEquals(val.toString(), obj.toString());

        }
}

@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.WRAPPER_OBJECT)
@JsonAutoDetect(fieldVisibility = Visibility.ANY, getterVisibility = Visibility.NONE, setterVisibility = Visibility.NONE)
@JsonSubTypes({ @JsonSubTypes.Type(value = Y.class),
                @JsonSubTypes.Type(value = Z.class),
                @JsonSubTypes.Type(value = N.class) })
interface X {
}

class N implements X {

        @Override
        public String toString() {
                return "N";
        }

}

class Y implements X {

        // NOT @JsonValue - works
        private final X value;

        @JsonCreator
        public Y(@JsonProperty("value") X val) {
                this.value = val;
        }

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

}

class Z implements X {
        @JsonValue
        private final X value;

        @JsonCreator
        public Z(X value) {
                this.value = value;
        }

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

}