PropertyBuilder.java

package org.codehaus.jackson.map.ser;

import java.lang.reflect.Field;
import java.lang.reflect.Method;

import org.codehaus.jackson.map.AnnotationIntrospector;
import org.codehaus.jackson.map.JsonSerializer;
import org.codehaus.jackson.map.SerializationConfig;
import org.codehaus.jackson.map.TypeSerializer;
import org.codehaus.jackson.map.annotate.JsonSerialize;
import org.codehaus.jackson.map.annotate.JsonSerialize.Inclusion;
import org.codehaus.jackson.map.introspect.Annotated;
import org.codehaus.jackson.map.introspect.AnnotatedField;
import org.codehaus.jackson.map.introspect.AnnotatedMember;
import org.codehaus.jackson.map.introspect.AnnotatedMethod;
import org.codehaus.jackson.map.introspect.BasicBeanDescription;
import org.codehaus.jackson.map.type.TypeFactory;
import org.codehaus.jackson.type.JavaType;

/**
 * Helper class for {@link BeanSerializerFactory} that is used to
 * construct {@link BeanPropertyWriter} instances. Can be sub-classed
 * to change behavior.
 */
public class PropertyBuilder
{
    final SerializationConfig _config;
    final BasicBeanDescription _beanDesc;
    final JsonSerialize.Inclusion _outputProps;

    final AnnotationIntrospector _annotationIntrospector;

    /**
     * If a property has serialization inclusion value of
     * {@link Inclusion#ALWAYS}, we need to know the default
     * value of the bean, to know if property value equals default
     * one.
     */
    protected Object _defaultBean;

    public PropertyBuilder(SerializationConfig config, BasicBeanDescription beanDesc)
    {
        _config = config;
        _beanDesc = beanDesc;
        _outputProps = beanDesc.findSerializationInclusion(config.getSerializationInclusion());
        _annotationIntrospector = _config.getAnnotationIntrospector();
    }

    /*
    /************************************************
    /* Public API
    /************************************************
     */

    /**
     * @param contentTypeSer Optional explicit type information serializer
     *    to use for contained values (only used for properties that are
     *    of container type)
     */
    protected BeanPropertyWriter buildProperty(String name, JsonSerializer<Object> ser,
            TypeSerializer typeSer, TypeSerializer contentTypeSer,
            AnnotatedMember am, boolean defaultUseStaticTyping)
    {
        Field f;
        Method m;
        if (am instanceof AnnotatedField) {
            m = null;
            f = ((AnnotatedField) am).getAnnotated();
        } else {
            m = ((AnnotatedMethod) am).getAnnotated();
            f = null;
        }

        // do we have annotation that forces type to use (to declared type or its super type)?
        JavaType serializationType = findSerializationType(am, defaultUseStaticTyping);
        // Container types can have separate type serializers for content (value / element) type
        if (contentTypeSer != null) {
            /* 04-Feb-2010, tatu: Let's force static typing for collection, if there is
             *    type information for contents. Should work well (for JAXB case); can be
             *    revisited if this causes problems.
             */
            if (serializationType == null) {
                serializationType = TypeFactory.type(am.getGenericType());
            }
            JavaType ct = serializationType.getContentType();
            ct.setTypeHandler(contentTypeSer);
        }
        Object suppValue = null;
        boolean suppressNulls = false;

        JsonSerialize.Inclusion methodProps = _annotationIntrospector.findSerializationInclusion(am, _outputProps);

        if (methodProps != null) {
            switch (methodProps) {
            case NON_DEFAULT:
                suppValue = getDefaultValue(name, m, f);
                if (suppValue == null) {
                    suppressNulls = true;
                }
                break;
            case NON_NULL:
                suppressNulls = true;
                break;
            }
        }
        return new BeanPropertyWriter(name, ser, typeSer, serializationType, m, f, suppressNulls, suppValue);
    }

    /*
    //////////////////////////////////////////////////
    // Helper methods, generic
    //////////////////////////////////////////////////
     */

    /**
     * Method that will try to determine statically defined type of property
     * being serialized, based on annotations (for overrides), and alternatively
     * declared type (if static typing for serialization is enabled).
     * If neither can be used (no annotations, dynamic typing), returns null.
     */
    protected JavaType findSerializationType(Annotated a, boolean useStaticTyping)
    {
        // [JACKSON-120]: Check to see if serialization type is fixed
        Class<?> serializationType = _annotationIntrospector.findSerializationType(a);
        if (serializationType != null) {
            // Must be a super type...
            Class<?> raw = a.getRawType();
            if (!serializationType.isAssignableFrom(raw)) {
                throw new IllegalArgumentException("Illegal concrete-type annotation for method '"+a.getName()+"': class "+serializationType.getName()+" not a super-type of (declared) class "+raw.getName());
            }
            return TypeFactory.type(serializationType);
        }
        /* [JACKSON-114]: if using static typing, declared type is known
         * to be the type...
         */
        JsonSerialize.Typing typing = _annotationIntrospector.findSerializationTyping(a);
        if (typing != null) {
            useStaticTyping = (typing == JsonSerialize.Typing.STATIC);
        }
        if (useStaticTyping) {
            return TypeFactory.type(a.getGenericType());
        }
        return null;
    }

    protected Object getDefaultBean()
    {
        if (_defaultBean == null) {
            /* If we can fix access rights, we should; otherwise non-public
             * classes or default constructor will prevent instantiation
             */
            _defaultBean = _beanDesc.instantiateBean(_config.isEnabled(SerializationConfig.Feature.CAN_OVERRIDE_ACCESS_MODIFIERS));
            if (_defaultBean == null) {
                Class<?> cls = _beanDesc.getClassInfo().getAnnotated();
                throw new IllegalArgumentException("Class "+cls.getName()+" has no default constructor; can not instantiate default bean value to support 'properties=JsonSerialize.Inclusion.NON_DEFAULT' annotation");
            }
        }
        return _defaultBean;
    }

    protected Object getDefaultValue(String name, Method m, Field f)
    {
        Object defaultBean = getDefaultBean();
        try {
            if (m != null) {
                return m.invoke(defaultBean);
            }
            return f.get(defaultBean);
        } catch (Exception e) {
            return _throwWrapped(e, name, defaultBean);
        }
    }

    protected Object _throwWrapped(Exception e, String propName, Object defaultBean)
    {
        Throwable t = e;
        while (t.getCause() != null) {
            t = t.getCause();
        }
        if (t instanceof Error) throw (Error) t;
        if (t instanceof RuntimeException) throw (RuntimeException) t;
        throw new IllegalArgumentException("Failed to get property '"+propName+"' of default "+defaultBean.getClass().getName()+" instance");
    }
}