Jackson Data Binding Source Code

Jackson is "the Java JSON library" or "the best JSON parser for Java". Or simply as "JSON for Java".

  • Jackson Data Binding module allows you to converts JSON to and from POJO (Plain Old Java Object) using property accessor or using annotations.
  • Jackson Databind Source Code files are provided in the source packge (jackson-databind-2.12.4-sources.jar). You can download it at Jackson Maven Website.

    You can also browse Jackson Databind Source Code below:

    ✍: FYIcenter.com

    com/fasterxml/jackson/databind/ser/impl/StringArraySerializer.java

    package com.fasterxml.jackson.databind.ser.impl;
    
    import java.io.IOException;
    import java.lang.reflect.Type;
    import java.util.Objects;
    
    import com.fasterxml.jackson.annotation.JsonFormat;
    
    import com.fasterxml.jackson.core.JsonGenerator;
    
    import com.fasterxml.jackson.databind.*;
    import com.fasterxml.jackson.databind.annotation.JacksonStdImpl;
    import com.fasterxml.jackson.databind.introspect.AnnotatedMember;
    import com.fasterxml.jackson.databind.jsonFormatVisitors.JsonFormatTypes;
    import com.fasterxml.jackson.databind.jsonFormatVisitors.JsonFormatVisitorWrapper;
    import com.fasterxml.jackson.databind.jsontype.TypeSerializer;
    import com.fasterxml.jackson.databind.ser.ContainerSerializer;
    import com.fasterxml.jackson.databind.ser.ContextualSerializer;
    import com.fasterxml.jackson.databind.ser.std.ArraySerializerBase;
    import com.fasterxml.jackson.databind.type.TypeFactory;
    
    /**
     * Standard serializer used for <code>String[]</code> values.
     */
    @JacksonStdImpl
    @SuppressWarnings("serial")
    public class StringArraySerializer
        extends ArraySerializerBase<String[]>
        implements ContextualSerializer
    {
        /* Note: not clean in general, but we are betting against
         * anyone re-defining properties of String.class here...
         */
        @SuppressWarnings("deprecation")
        private final static JavaType VALUE_TYPE = TypeFactory.defaultInstance().uncheckedSimpleType(String.class);
    
        public final static StringArraySerializer instance = new StringArraySerializer();
    
        /**
         * Value serializer to use, if it's not the standard one
         * (if it is we can optimize serialization a lot)
         */
        protected final JsonSerializer<Object> _elementSerializer;
    
        /*
        /**********************************************************
        /* Life-cycle
        /**********************************************************
         */
        
        protected StringArraySerializer() {
            super(String[].class);
            _elementSerializer = null;
        }
    
        @SuppressWarnings("unchecked")
        public StringArraySerializer(StringArraySerializer src,
                BeanProperty prop, JsonSerializer<?> ser, Boolean unwrapSingle) {
            super(src, prop, unwrapSingle);
            _elementSerializer = (JsonSerializer<Object>) ser;
        }
    
        @Override
        public JsonSerializer<?> _withResolved(BeanProperty prop, Boolean unwrapSingle) {
            return new StringArraySerializer(this, prop, _elementSerializer, unwrapSingle);
        }
    
        /**
         * Strings never add type info; hence, even if type serializer is suggested,
         * we'll ignore it...
         */
        @Override
        public ContainerSerializer<?> _withValueTypeSerializer(TypeSerializer vts) {
            return this;
        }
    
        /*
        /**********************************************************
        /* Post-processing
        /**********************************************************
         */
        
        @Override
        public JsonSerializer<?> createContextual(SerializerProvider provider,
                BeanProperty property)
            throws JsonMappingException
        {
            /* 29-Sep-2012, tatu: Actually, we need to do much more contextual
             *    checking here since we finally know for sure the property,
             *    and it may have overrides
             */
            JsonSerializer<?> ser = null;
    
            // First: if we have a property, may have property-annotation overrides
            if (property != null) {
                final AnnotationIntrospector ai = provider.getAnnotationIntrospector();
                AnnotatedMember m = property.getMember();
                if (m != null) {
                    Object serDef = ai.findContentSerializer(m);
                    if (serDef != null) {
                        ser = provider.serializerInstance(m, serDef);
                    }
                }
            }
            // but since formats have both property overrides and global per-type defaults,
            // need to do that separately
            Boolean unwrapSingle = findFormatFeature(provider, property, String[].class,
                    JsonFormat.Feature.WRITE_SINGLE_ELEM_ARRAYS_UNWRAPPED);
            if (ser == null) {
                ser = _elementSerializer;
            }
            // May have a content converter
            ser = findContextualConvertingSerializer(provider, property, ser);
            if (ser == null) {
                ser = provider.findContentValueSerializer(String.class, property);
            }
            // Optimization: default serializer just writes String, so we can avoid a call:
            if (isDefaultSerializer(ser)) {
                ser = null;
            }
            // note: will never have TypeSerializer, because Strings are "natural" type
            if ((ser == _elementSerializer) && (Objects.equals(unwrapSingle, _unwrapSingle))) {
                return this;
            }
            return new StringArraySerializer(this, property, ser, unwrapSingle);
        }
    
        /*
        /**********************************************************
        /* Simple accessors
        /**********************************************************
         */
    
        @Override
        public JavaType getContentType() {
            return VALUE_TYPE;
        }
    
        @Override
        public JsonSerializer<?> getContentSerializer() {
            return _elementSerializer;
        }
        
        @Override
        public boolean isEmpty(SerializerProvider prov, String[] value) {
            return (value.length == 0);
        }
    
        @Override
        public boolean hasSingleElement(String[] value) {
            return (value.length == 1);
        }
        
        /*
        /**********************************************************
        /* Actual serialization
        /**********************************************************
         */
        
        @Override
        public final void serialize(String[] value, JsonGenerator gen, SerializerProvider provider)
            throws IOException
        {
            final int len = value.length;
            if (len == 1) {
                if (((_unwrapSingle == null) &&
                        provider.isEnabled(SerializationFeature.WRITE_SINGLE_ELEM_ARRAYS_UNWRAPPED))
                        || (_unwrapSingle == Boolean.TRUE)) {
                    serializeContents(value, gen, provider);
                    return;
                }
            }
            gen.writeStartArray(value, len);
            serializeContents(value, gen, provider);
            gen.writeEndArray();
        }
        
        @Override
        public void serializeContents(String[] value, JsonGenerator gen, SerializerProvider provider)
            throws IOException
        {
            final int len = value.length;
            if (len == 0) {
                return;
            }
            if (_elementSerializer != null) {
                serializeContentsSlow(value, gen, provider, _elementSerializer);
                return;
            }
            for (int i = 0; i < len; ++i) {
                String str = value[i];
                if (str == null) {
                    gen.writeNull();
                } else {
                    gen.writeString(value[i]);
                }
            }
        }
    
        private void serializeContentsSlow(String[] value, JsonGenerator gen, SerializerProvider provider, JsonSerializer<Object> ser)
            throws IOException
        {
            for (int i = 0, len = value.length; i < len; ++i) {
                String str = value[i];
                if (str == null) {
                    provider.defaultSerializeNull(gen);
                } else {
                    ser.serialize(value[i], gen, provider);
                }
            }
        }
    
        @Override
        public JsonNode getSchema(SerializerProvider provider, Type typeHint) {
            return createSchemaNode("array", true).set("items", createSchemaNode("string"));
        }
        
        @Override
        public void acceptJsonFormatVisitor(JsonFormatVisitorWrapper visitor, JavaType typeHint) throws JsonMappingException
        {
            visitArrayFormat(visitor, typeHint, JsonFormatTypes.STRING);
        }
    }
    

    com/fasterxml/jackson/databind/ser/impl/StringArraySerializer.java

     

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    2022-03-29, 32320👍, 0💬