/*
* Copyright 2014-2015 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.data.rest.webmvc.json;
import java.util.Iterator;
import java.util.List;
import org.springframework.data.mapping.PersistentProperty;
import org.springframework.data.rest.core.annotation.Description;
import org.springframework.data.rest.core.mapping.AnnotationBasedResourceDescription;
import org.springframework.data.rest.core.mapping.ResourceDescription;
import org.springframework.data.rest.core.mapping.ResourceMetadata;
import org.springframework.data.rest.core.mapping.TypedResourceDescription;
import org.springframework.util.Assert;
import com.fasterxml.jackson.databind.BeanDescription;
import com.fasterxml.jackson.databind.DeserializationConfig;
import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationConfig;
import com.fasterxml.jackson.databind.SerializerProvider;
import com.fasterxml.jackson.databind.introspect.AnnotatedMember;
import com.fasterxml.jackson.databind.introspect.BeanPropertyDefinition;
import com.fasterxml.jackson.databind.ser.DefaultSerializerProvider;
/**
* Value object to abstract Jackson based bean metadata of a given type.
*
* @author Oliver Gierke
* @author Greg Turnquist
*/
public class JacksonMetadata implements Iterable<BeanPropertyDefinition> {
private final ObjectMapper mapper;
private final List<BeanPropertyDefinition> definitions;
private final List<BeanPropertyDefinition> deserializationDefinitions;
private final boolean isValue;
/**
* Creates a new {@link JacksonMetadata} instance for the given {@link ObjectMapper} and type.
*
* @param mapper must not be {@literal null}.
* @param type must not be {@literal null}.
*/
public JacksonMetadata(ObjectMapper mapper, Class<?> type) {
Assert.notNull(mapper, "ObjectMapper must not be null!");
Assert.notNull(type, "Type must not be null!");
this.mapper = mapper;
SerializationConfig serializationConfig = mapper.getSerializationConfig();
JavaType javaType = serializationConfig.constructType(type);
BeanDescription description = serializationConfig.introspect(javaType);
this.definitions = description.findProperties();
this.isValue = description.findJsonValueMethod() != null;
DeserializationConfig deserializationConfig = mapper.getDeserializationConfig();
JavaType deserializationType = deserializationConfig.constructType(type);
this.deserializationDefinitions = deserializationConfig.introspect(deserializationType).findProperties();
}
/**
* Returns the {@link BeanPropertyDefinition} for the given {@link PersistentProperty}.
*
* @param property must not be {@literal null}.
* @return can be {@literal null} in case there's no Jackson property to be exposed for the given
* {@link PersistentProperty}.
*/
public BeanPropertyDefinition getDefinitionFor(PersistentProperty<?> property) {
Assert.notNull(property, "PersistentProperty must not be null!");
return getDefinitionFor(property, definitions);
}
/**
* Returns the fallback {@link ResourceDescription} to be used for the given {@link BeanPropertyDefinition}.
*
* @param ownerMetadata must not be {@literal null}.
* @param definition must not be {@literal null}.
* @return
*/
public ResourceDescription getFallbackDescription(ResourceMetadata ownerMetadata, BeanPropertyDefinition definition) {
Assert.notNull(ownerMetadata, "Owner's resource metadata must not be null!");
Assert.notNull(definition, "BeanPropertyDefinition must not be null!");
AnnotatedMember member = definition.getPrimaryMember();
Description description = member.getAnnotation(Description.class);
ResourceDescription fallback = TypedResourceDescription.defaultFor(ownerMetadata.getItemResourceRel(),
definition.getInternalName(), definition.getPrimaryMember().getRawType());
return description == null ? fallback : new AnnotationBasedResourceDescription(description, fallback);
}
/**
* Check if a given property for a type is available to be exported, i.e. serialized via Jackson.
*
* @param property must not be {@literal null}.
* @return
*/
public boolean isExported(PersistentProperty<?> property) {
Assert.notNull(property, "PersistentProperty must not be null!");
return getDefinitionFor(property) != null;
}
/**
* Returns whether the backing type is considered a Jackson value type.
*
* @return the isValue
*/
public boolean isValueType() {
return isValue;
}
/**
* Returns whether the given {@link PersistentProperty} is considered read-only by Jackson.
*
* @param property must not be {@literal null}.
* @return
*/
public boolean isReadOnly(PersistentProperty<?> property) {
BeanPropertyDefinition definition = getDefinitionFor(property, deserializationDefinitions);
return definition == null ? false : !definition.couldDeserialize();
}
/**
* Returns the {@link JsonSerializer} for the given type, or {@literal null} if none available.
*
* @param type must not be {@literal null}.
* @return
*/
public JsonSerializer<?> getTypeSerializer(Class<?> type) {
Assert.notNull(type, "Type must not be null!");
try {
SerializerProvider provider = mapper.getSerializerProvider();
if (!(provider instanceof DefaultSerializerProvider)) {
return null;
}
provider = ((DefaultSerializerProvider) provider).createInstance(mapper.getSerializationConfig(),
mapper.getSerializerFactory());
return provider.findValueSerializer(type);
} catch (JsonMappingException o_O) {
return null;
}
}
/*
* (non-Javadoc)
* @see java.lang.Iterable#iterator()
*/
@Override
public Iterator<BeanPropertyDefinition> iterator() {
return definitions.iterator();
}
/**
* Finds the {@link BeanPropertyDefinition} for the given {@link PersistentProperty} within the given definitions.
*
* @param property must not be {@literal null}.
* @param definitions must not be {@literal null}.
* @return
*/
private static BeanPropertyDefinition getDefinitionFor(PersistentProperty<?> property,
Iterable<BeanPropertyDefinition> definitions) {
for (BeanPropertyDefinition definition : definitions) {
if (definition.getInternalName().equals(property.getName())) {
return definition;
}
}
return null;
}
}