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package com.fasterxml.jackson.databind;

import java.lang.reflect.Type;

import com.fasterxml.jackson.annotation.ObjectIdGenerator;

import com.fasterxml.jackson.databind.annotation.NoClass;
import com.fasterxml.jackson.databind.cfg.HandlerInstantiator;
import com.fasterxml.jackson.databind.cfg.MapperConfig;
import com.fasterxml.jackson.databind.introspect.Annotated;
import com.fasterxml.jackson.databind.introspect.ObjectIdInfo;
import com.fasterxml.jackson.databind.type.TypeFactory;
import com.fasterxml.jackson.databind.util.ClassUtil;
import com.fasterxml.jackson.databind.util.Converter;

/**
 * Shared base class for {@link DeserializationContext} and
 * {@link SerializerProvider}, context objects passed through data-binding
 * process. Designed so that some of implementations can rely on shared
 * aspects like access to secondary contextual objects like type factories
 * or handler instantiators.
 * 
 * @since 2.2
 */
public abstract class DatabindContext
{
    /*
    /**********************************************************
    /* Generic config access
    /**********************************************************
     */

    /**
     * Accessor to currently active configuration (both per-request configs
     * and per-mapper config).
     */
    public abstract MapperConfig getConfig();

    /**
     * Convenience method for accessing serialization view in use (if any); equivalent to:
     *
     *   getConfig().getAnnotationIntrospector();
     *
*/ public abstract AnnotationIntrospector getAnnotationIntrospector(); /* /********************************************************** /* Access to specific config settings /********************************************************** */ /** * Convenience method for checking whether specified serialization * feature is enabled or not. * Shortcut for: *
     *  getConfig().isEnabled(feature);
     *
*/ public final boolean isEnabled(MapperFeature feature) { return getConfig().isEnabled(feature); } /** * Convenience method for accessing serialization view in use (if any); equivalent to: *
     *   getConfig().canOverrideAccessModifiers();
     *
*/ public final boolean canOverrideAccessModifiers() { return getConfig().canOverrideAccessModifiers(); } /** * Accessor for locating currently active view, if any; * returns null if no view has been set. */ public abstract Class getActiveView(); /* /********************************************************** /* Generic attributes (2.3+) /********************************************************** */ /** * Method for accessing attributes available in this context. * Per-call attributes have highest precedence; attributes set * via {@link ObjectReader} or {@link ObjectWriter} have lower * precedence. * * @param key Key of the attribute to get * @return Value of the attribute, if any; null otherwise * * @since 2.3 */ public abstract Object getAttribute(Object key); /** * Method for setting per-call value of given attribute. * This will override any previously defined value for the * attribute within this context. * * @param key Key of the attribute to set * @param value Value to set attribute to * * @return This context object, to allow chaining * * @since 2.3 */ public abstract DatabindContext setAttribute(Object key, Object value); /* /********************************************************** /* Type instantiation/resolution /********************************************************** */ /** * Convenience method for constructing {@link JavaType} for given JDK * type (usually {@link java.lang.Class}) */ public JavaType constructType(Type type) { return getTypeFactory().constructType(type); } /** * Convenience method for constructing subtypes, retaining generic * type parameter (if any) */ public JavaType constructSpecializedType(JavaType baseType, Class subclass) { // simple optimization to avoid costly introspection if type-erased type does NOT differ if (baseType.getRawClass() == subclass) { return baseType; } return getConfig().constructSpecializedType(baseType, subclass); } public abstract TypeFactory getTypeFactory(); /* /********************************************************** /* Helper object construction /********************************************************** */ public ObjectIdGenerator objectIdGeneratorInstance(Annotated annotated, ObjectIdInfo objectIdInfo) throws JsonMappingException { Class implClass = objectIdInfo.getGeneratorType(); final MapperConfig config = getConfig(); HandlerInstantiator hi = config.getHandlerInstantiator(); ObjectIdGenerator gen = (hi == null) ? null : hi.objectIdGeneratorInstance(config, annotated, implClass); if (gen == null) { gen = (ObjectIdGenerator) ClassUtil.createInstance(implClass, config.canOverrideAccessModifiers()); } return gen.forScope(objectIdInfo.getScope()); } /** * Helper method to use to construct a {@link Converter}, given a definition * that may be either actual converter instance, or Class for instantiating one. * * @since 2.2 */ @SuppressWarnings("unchecked") public Converter converterInstance(Annotated annotated, Object converterDef) throws JsonMappingException { if (converterDef == null) { return null; } if (converterDef instanceof Converter) { return (Converter) converterDef; } if (!(converterDef instanceof Class)) { throw new IllegalStateException("AnnotationIntrospector returned Converter definition of type " +converterDef.getClass().getName()+"; expected type Converter or Class instead"); } Class converterClass = (Class)converterDef; // there are some known "no class" markers to consider too: if (converterClass == Converter.None.class || converterClass == NoClass.class) { return null; } if (!Converter.class.isAssignableFrom(converterClass)) { throw new IllegalStateException("AnnotationIntrospector returned Class " +converterClass.getName()+"; expected Class"); } final MapperConfig config = getConfig(); HandlerInstantiator hi = config.getHandlerInstantiator(); Converter conv = (hi == null) ? null : hi.converterInstance(config, annotated, converterClass); if (conv == null) { conv = (Converter) ClassUtil.createInstance(converterClass, config.canOverrideAccessModifiers()); } return (Converter) conv; } }




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