com.fasterxml.jackson.databind.ser.std.ArraySerializerBase Maven / Gradle / Ivy

package com.fasterxml.jackson.databind.ser.std;

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

import com.fasterxml.jackson.annotation.JsonFormat;

import com.fasterxml.jackson.core.*;
import com.fasterxml.jackson.core.type.WritableTypeId;

import com.fasterxml.jackson.databind.*;
import com.fasterxml.jackson.databind.jsontype.TypeSerializer;
import com.fasterxml.jackson.databind.ser.*;

/**
 * Intermediate base class for serializers used for various
 * Java arrays.
 * 
 * @param  Type of arrays serializer handles
 */
@SuppressWarnings("serial")
public abstract class ArraySerializerBase
    extends ContainerSerializer
    implements ContextualSerializer // for 'unwrapSingleElemArray'
{
    protected final BeanProperty _property;

    /**
     * Setting for specific local override for "unwrap single element arrays":
     * true for enable unwrapping, false for preventing it, `null` for using
     * global configuration.
     *
     * @since 2.6
     */
    protected final Boolean _unwrapSingle;

    protected ArraySerializerBase(Class cls)
    {
        super(cls);
        _property = null;
        _unwrapSingle = null;
    }

    /**
     * Use either variant that just takes type (non-contextual), or,
     * copy constructor that allows passing of property.
     *
     * @deprecated Since 2.6
     */
    @Deprecated
    protected ArraySerializerBase(Class cls, BeanProperty property)
    {
        super(cls);
        _property = property;
        _unwrapSingle = null;
    }

    protected ArraySerializerBase(ArraySerializerBase src)
    {
        super(src._handledType, false);
        _property = src._property;
        _unwrapSingle = src._unwrapSingle;
    }

    /**
     * @since 2.6
     */
    protected ArraySerializerBase(ArraySerializerBase src, BeanProperty property,
            Boolean unwrapSingle)
    {
        super(src._handledType, false);
        _property = property;
        _unwrapSingle = unwrapSingle;
    }

    /**
     * @deprecated Since 2.6
     */
    @Deprecated
    protected ArraySerializerBase(ArraySerializerBase src, BeanProperty property)
    {
        super(src._handledType, false);
        _property = property;
        _unwrapSingle = src._unwrapSingle;
    }

    /**
     * @since 2.6
     */
    public abstract JsonSerializer _withResolved(BeanProperty prop,
            Boolean unwrapSingle);

    @Override
    public JsonSerializer createContextual(SerializerProvider serializers,
            BeanProperty property) throws JsonMappingException
    {
        Boolean unwrapSingle = null;

        // First: if we have a property, may have property-annotation overrides
        if (property != null) {
            JsonFormat.Value format = findFormatOverrides(serializers, property, handledType());
            if (format != null) {
                unwrapSingle = format.getFeature(JsonFormat.Feature.WRITE_SINGLE_ELEM_ARRAYS_UNWRAPPED);
                if (!Objects.equals(unwrapSingle, _unwrapSingle)) {
                    return _withResolved(property, unwrapSingle);
                }
            }
        }
        return this;
    }
    
    // NOTE: as of 2.5, sub-classes SHOULD override (in 2.4 and before, was final),
    // at least if they can provide access to actual size of value and use `writeStartArray()`
    // variant that passes size of array to output, which is helpful with some data formats
    @Override
    public void serialize(T value, JsonGenerator gen, SerializerProvider provider) throws IOException
    {
        if (_shouldUnwrapSingle(provider)) {
            if (hasSingleElement(value)) {
                serializeContents(value, gen, provider);
                return;
            }
        }
        gen.writeStartArray(value);
        serializeContents(value, gen, provider);
        gen.writeEndArray();
    }

    @Override
    public final void serializeWithType(T value, JsonGenerator g, SerializerProvider provider,
            TypeSerializer typeSer)
        throws IOException
    {
        WritableTypeId typeIdDef = typeSer.writeTypePrefix(g,
                typeSer.typeId(value, JsonToken.START_ARRAY));
        // [databind#631]: Assign current value, to be accessible by custom serializers
        g.setCurrentValue(value);
        serializeContents(value, g, provider);
        typeSer.writeTypeSuffix(g, typeIdDef);
    }

    protected abstract void serializeContents(T value, JsonGenerator jgen, SerializerProvider provider)
        throws IOException;

    /**
     * @since 2.9
     */
    protected final boolean _shouldUnwrapSingle(SerializerProvider provider) {
        if (_unwrapSingle == null) {
            return provider.isEnabled(SerializationFeature.WRITE_SINGLE_ELEM_ARRAYS_UNWRAPPED);
        }
        return _unwrapSingle.booleanValue();
    }
}