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

Jackson Annotations Source Code files are provided in the source packge (jackson-annotations-2.12.4-sources.jar). You can download it at Jackson Maven Website.

You can also browse Jackson Annotations Source Code below:

⏎ com/fasterxml/jackson/databind/deser/std/StdScalarDeserializer.java

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

import java.io.IOException;

import com.fasterxml.jackson.core.*;
import com.fasterxml.jackson.databind.*;
import com.fasterxml.jackson.databind.jsontype.TypeDeserializer;
import com.fasterxml.jackson.databind.type.LogicalType;
import com.fasterxml.jackson.databind.util.AccessPattern;

/**
 * Base class for deserializers that handle types that are serialized
 * as JSON scalars (non-structured, i.e. non-Object, non-Array, values).
 */
public abstract class StdScalarDeserializer<T> extends StdDeserializer<T>
{
    private static final long serialVersionUID = 1L;

    protected StdScalarDeserializer(Class<?> vc) { super(vc); }
    protected StdScalarDeserializer(JavaType valueType) { super(valueType); }

    // since 2.5
    protected StdScalarDeserializer(StdScalarDeserializer<?> src) { super(src); }

    /*
    /**********************************************************************
    /* Overridden accessors
    /**********************************************************************
     */

    @Override // since 2.12
    public LogicalType logicalType() {
        return LogicalType.OtherScalar;
    }

    /**
     * By default assumption is that scalar types cannot be updated: many are immutable
     * values (such as primitives and wrappers)
     */
    @Override // since 2.9
    public Boolean supportsUpdate(DeserializationConfig config) {
        return Boolean.FALSE;
    }

    // Typically Scalar values have default setting of "nulls as nulls"
    @Override
    public AccessPattern getNullAccessPattern() {
        return AccessPattern.ALWAYS_NULL;
    }

    // While some scalar types have non-null empty values (hence can't say "ALWAYS_NULL")
    // they are mostly immutable, shareable and so constant.
    @Override // since 2.9
    public AccessPattern getEmptyAccessPattern() {
        return AccessPattern.CONSTANT;
    }

    /*
    /**********************************************************************
    /* Default deserialization method impls
    /**********************************************************************
     */

    @Override
    public Object deserializeWithType(JsonParser p, DeserializationContext ctxt, TypeDeserializer typeDeserializer) throws IOException {
        return typeDeserializer.deserializeTypedFromScalar(p, ctxt);
    }

    /**
     * Overridden to simply call <code>deserialize()</code> method that does not take value
     * to update, since scalar values are usually non-mergeable.
     */
    @Override // since 2.9
    public T deserialize(JsonParser p, DeserializationContext ctxt, T intoValue) throws IOException {
        // 25-Oct-2016, tatu: And if attempt is made, see if we are to complain...
        ctxt.handleBadMerge(this);
        // if that does not report an exception we can just delegate
        return deserialize(p, ctxt);
    }
}

⏎ com/fasterxml/jackson/databind/deser/std/StdScalarDeserializer.java

 

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