All Downloads are FREE. Search and download functionalities are using the official Maven repository.
  • Log In
  • Register

    • com.fasterxml.jackson.databind.deser.std.StdDelegatingDeserializer Maven / Gradle / Ivy

    Go to download

    This artifact provides a single jar that contains all classes required to use remote Jakarta Enterprise Beans and Jakarta Messaging, including all dependencies. It is intended for use by those not using maven, maven users should just import the Jakarta Enterprise Beans and Jakarta Messaging BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up with different versions on classes on the class path).

    There is a newer version: 35.0.0.Beta1
    Show newest version
    package com.fasterxml.jackson.databind.deser.std;

import java.io.IOException;

import com.fasterxml.jackson.core.JsonParser;

import com.fasterxml.jackson.databind.*;
import com.fasterxml.jackson.databind.deser.ContextualDeserializer;
import com.fasterxml.jackson.databind.deser.ResolvableDeserializer;
import com.fasterxml.jackson.databind.jsontype.TypeDeserializer;
import com.fasterxml.jackson.databind.type.LogicalType;
import com.fasterxml.jackson.databind.util.ClassUtil;
import com.fasterxml.jackson.databind.util.Converter;

/**
 * Deserializer implementation where given Java type is first deserialized
 * by a standard Jackson deserializer into a delegate type; and then
 * this delegate type is converted using a configured
 * {@link Converter} into desired target type.
 * Common delegate types to use are {@link java.util.Map}
 * and {@link com.fasterxml.jackson.databind.JsonNode}.
 *
    
 * Note that although types (delegate, target) may be related, they must not be same; trying
 * to do this will result in an exception.
 *
    
 * Since 2.5 There is {@link StdNodeBasedDeserializer} that is a simplified version
 * for cases where intermediate type is {@link JsonNode}
 * 
 * @param  Target type to convert to, from delegate type
 * 
 * @since 2.1
 * 
 * @see StdNodeBasedDeserializer
 * @see Converter
 */
public class StdDelegatingDeserializer
    extends StdDeserializer
    implements ContextualDeserializer, ResolvableDeserializer
{
    private static final long serialVersionUID = 1L;

    /**
     * Converter that was used for creating {@link #_delegateDeserializer}.
     */
    protected final Converter _converter;

    /**
     * Fully resolved delegate type, with generic information if any available.
     */
    protected final JavaType _delegateType;

    /**
     * Underlying serializer for type T.
     */
    protected final JsonDeserializer _delegateDeserializer;

    /*
    /**********************************************************
    /* Life-cycle
    /**********************************************************
     */

    @SuppressWarnings("unchecked")
    public StdDelegatingDeserializer(Converter converter)
    {
        super(Object.class);
        _converter = (Converter)converter;
        _delegateType = null;
        _delegateDeserializer = null;
    }

    @SuppressWarnings("unchecked")
    public StdDelegatingDeserializer(Converter converter,
            JavaType delegateType, JsonDeserializer delegateDeserializer)
    {
        super(delegateType);
        _converter = converter;
        _delegateType = delegateType;
        _delegateDeserializer = (JsonDeserializer) delegateDeserializer;
    }

    /**
     * @since 2.5
     */
    protected StdDelegatingDeserializer(StdDelegatingDeserializer src)
    {
        super(src);
        _converter = src._converter;
        _delegateType = src._delegateType;
        _delegateDeserializer = src._delegateDeserializer;
    }

    /**
     * Method used for creating resolved contextual instances. Must be
     * overridden when sub-classing.
     */
    protected StdDelegatingDeserializer withDelegate(Converter converter,
            JavaType delegateType, JsonDeserializer delegateDeserializer)
    {
        ClassUtil.verifyMustOverride(StdDelegatingDeserializer.class, this, "withDelegate");
        return new StdDelegatingDeserializer(converter, delegateType, delegateDeserializer);
    }

    /*
    /**********************************************************
    /* Contextualization
    /**********************************************************
     */

    // Note: unlikely to get called since most likely instances explicitly constructed;
    // if so, caller must ensure delegating deserializer is properly resolve()d.
    @Override
    public void resolve(DeserializationContext ctxt)
        throws JsonMappingException
    {
        if (_delegateDeserializer != null && _delegateDeserializer instanceof ResolvableDeserializer) {
            ((ResolvableDeserializer) _delegateDeserializer).resolve(ctxt);
        }
    }

    @Override
    public JsonDeserializer createContextual(DeserializationContext ctxt, BeanProperty property)
        throws JsonMappingException
    {
        // First: if already got deserializer to delegate to, contextualize it:
        if (_delegateDeserializer != null) {
            JsonDeserializer deser = ctxt.handleSecondaryContextualization(_delegateDeserializer,
                    property, _delegateType);
            if (deser != _delegateDeserializer) {
                return withDelegate(_converter, _delegateType, deser);
            }
            return this;
        }
        // Otherwise: figure out what is the fully generic delegate type, then find deserializer
        JavaType delegateType = _converter.getInputType(ctxt.getTypeFactory());
        return withDelegate(_converter, delegateType,
                ctxt.findContextualValueDeserializer(delegateType, property));
    }

    /*
    /**********************************************************
    /* Accessors
    /**********************************************************
     */

    @Override
    public JsonDeserializer getDelegatee() {
        return _delegateDeserializer;
    }

    @Override
    public Class handledType() {
        return _delegateDeserializer.handledType();
    }

    @Override // since 2.12
    public LogicalType logicalType() {
        return _delegateDeserializer.logicalType();
    }
    
    @Override // since 2.9
    public Boolean supportsUpdate(DeserializationConfig config) {
        return _delegateDeserializer.supportsUpdate(config);
    }

    /*
    /**********************************************************
    /* Serialization
    /**********************************************************
     */
    
    @Override
    public T deserialize(JsonParser p, DeserializationContext ctxt) throws IOException
    {
        Object delegateValue = _delegateDeserializer.deserialize(p, ctxt);
        if (delegateValue == null) {
            return null;
        }
        return convertValue(delegateValue);
    }

    @Override
    public Object deserializeWithType(JsonParser p, DeserializationContext ctxt,
            TypeDeserializer typeDeserializer) throws IOException
    {
        /* 12-Apr-2016, tatu: As predicted, earlier handling does not work
         *   (see [databind#1189] for details). There does not seem to be any compelling
         *   way to combine polymorphic types, Converters, but the least sucky way
         *   is probably to use Converter and ignore polymorphic type. Alternative
         *   would be to try to change `TypeDeserializer` to accept `Converter` to
         *   invoke... but that is more intrusive, yet not guaranteeing success.
         */
        // method called up to 2.7.3:
//        Object delegateValue = _delegateDeserializer.deserializeWithType(p, ctxt, typeDeserializer);

        // method called since 2.7.4
        Object delegateValue = _delegateDeserializer.deserialize(p, ctxt);
        if (delegateValue == null) {
            return null;
        }
        return convertValue(delegateValue);
    }

    @SuppressWarnings("unchecked")
    @Override
    public T deserialize(JsonParser p, DeserializationContext ctxt, Object intoValue)
        throws IOException
    {
        if (_delegateType.getRawClass().isAssignableFrom(intoValue.getClass())){
            return (T) _delegateDeserializer.deserialize(p, ctxt, intoValue);
        }
        return (T) _handleIncompatibleUpdateValue(p, ctxt, intoValue);
    }

    /**
     * Overridable handler method called when {@link #deserialize(JsonParser, DeserializationContext, Object)}
     * has been called with a value that is not compatible with delegate value.
     * Since no conversion are expected for such "updateValue" case, this is normally not
     * an operation that can be permitted, and the default behavior is to throw exception.
     * Sub-classes may choose to try alternative approach if they have more information on
     * exact usage and constraints.
     *
     * @since 2.6
     */
    protected Object _handleIncompatibleUpdateValue(JsonParser p, DeserializationContext ctxt, Object intoValue)
        throws IOException
    {
        throw new UnsupportedOperationException(String.format
                ("Cannot update object of type %s (using deserializer for type %s)"
                        +intoValue.getClass().getName(), _delegateType));
    }
    
    /*
    /**********************************************************
    /* Overridable methods
    /**********************************************************
     */

    /**
     * Method called to convert from "delegate value" (which was deserialized
     * from JSON using standard Jackson deserializer for delegate type)
     * into desired target type.
     *
    
     * The default implementation uses configured {@link Converter} to do
     * conversion.
     * 
     * @param delegateValue
     * 
     * @return Result of conversion
     */
    protected T convertValue(Object delegateValue) {
        return _converter.convert(delegateValue);
    }
}
    
    
    
    

    




    
    
    © 2015 - 2025 Weber Informatics LLC | Privacy Policy