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Tridion OData Framework Renderer Implementation
/**
* Copyright (c) 2014 All Rights Reserved by the SDL Group.
*
* 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 com.sdl.odata.renderer.atom.writer;
import com.sdl.odata.api.edm.model.EntityDataModel;
import com.sdl.odata.api.edm.model.EntityType;
import com.sdl.odata.api.edm.model.EnumType;
import com.sdl.odata.api.edm.model.MetaType;
import com.sdl.odata.api.edm.model.NavigationProperty;
import com.sdl.odata.api.edm.model.PrimitiveType;
import com.sdl.odata.api.edm.model.StructuralProperty;
import com.sdl.odata.api.edm.model.StructuredType;
import com.sdl.odata.api.edm.model.Type;
import com.sdl.odata.api.edm.model.TypeDefinition;
import com.sdl.odata.api.renderer.ODataRenderException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamWriter;
import java.lang.reflect.Field;
import java.util.Arrays;
import java.util.Collection;
import java.util.Iterator;
import static com.sdl.odata.AtomConstants.COLLECTION;
import static com.sdl.odata.AtomConstants.ELEMENT;
import static com.sdl.odata.AtomConstants.HASH;
import static com.sdl.odata.AtomConstants.METADATA;
import static com.sdl.odata.AtomConstants.NULL;
import static com.sdl.odata.AtomConstants.ODATA_CONTENT;
import static com.sdl.odata.AtomConstants.ODATA_DATA;
import static com.sdl.odata.AtomConstants.ODATA_PROPERTIES;
import static com.sdl.odata.AtomConstants.TYPE;
import static com.sdl.odata.ODataRendererUtils.checkNotNull;
import static com.sdl.odata.api.service.MediaType.XML;
import static com.sdl.odata.util.edm.EntityDataModelUtil.visitProperties;
/**
*
* Helper writer capable of writing OData data elements for an {@code } element.
*
*
* Please note that it is necessary to open the XML writer used by instances of this class before calling any method,
* and close it after the writing process is finished.
*
*/
public class AtomDataWriter {
private static final Logger LOG = LoggerFactory.getLogger(AtomDataWriter.class);
private final XMLStreamWriter xmlWriter;
private final EntityDataModel entityDataModel;
private final AtomNSConfigurationProvider nsConfigurationProvider;
/**
* Creates an instance of {@link AtomDataWriter} by specifying the writer to use.
*
* @param xmlWriter The XML writer to use. It can not be {@code null}.
* @param entityDataModel The Entity Data Model. It can not be {@code null}.
* @param nsConfigurationProvider The NameSpace provider to provide OData Atom specific namespaces.
*/
public AtomDataWriter(XMLStreamWriter xmlWriter, EntityDataModel entityDataModel,
AtomNSConfigurationProvider nsConfigurationProvider) {
this.xmlWriter = checkNotNull(xmlWriter);
this.entityDataModel = checkNotNull(entityDataModel);
this.nsConfigurationProvider = checkNotNull(nsConfigurationProvider);
}
/**
* Write the data for a given entity.
*
* @param entity The given entity.
* @param entityType The entity type.
* @throws XMLStreamException if unable to render the entity
* @throws ODataRenderException if unable to render the entity
*/
public void writeData(Object entity, EntityType entityType) throws XMLStreamException, ODataRenderException {
xmlWriter.writeStartElement(ODATA_CONTENT);
xmlWriter.writeAttribute(TYPE, XML.toString());
xmlWriter.writeStartElement(METADATA, ODATA_PROPERTIES, "");
marshall(entity, entityType);
xmlWriter.writeEndElement();
xmlWriter.writeEndElement();
}
/**
* Marshall an object with a given OData type.
*
* @param object The object to marshall. Can be {@code null}.
* @param type The OData type of the object.
* @throws XMLStreamException If an error occurs while marshalling.
*/
private void marshall(Object object, Type type) throws XMLStreamException, ODataRenderException {
// Decide what to do depending on what kind of type this is
switch (type.getMetaType()) {
case ABSTRACT:
throw new UnsupportedOperationException("Marshalling abstract OData types is not supported");
case PRIMITIVE:
marshallPrimitive(object, (PrimitiveType) type);
break;
case ENTITY:
case COMPLEX:
marshallStructured(object, (StructuredType) type);
break;
case ENUM:
marshallEnum(object, (EnumType) type);
break;
case TYPE_DEFINITION:
marshallPrimitive(object, ((TypeDefinition) type).getUnderlyingType());
break;
default:
throw new UnsupportedOperationException("Unsupported type: " + type);
}
}
/**
* Marshall a primitive value.
*
* @param value The value to marshall. Can be {@code null}.
* @param primitiveType The OData primitive type.
*/
private void marshallPrimitive(Object value, PrimitiveType primitiveType) throws XMLStreamException {
LOG.debug("Primitive value: {} of type: {}", value, primitiveType);
if (value != null) {
xmlWriter.writeCharacters(value.toString());
}
}
/**
* Marshall an object that is of an OData structured type (entity type or complex type).
*
* @param object The object to marshall. Can be {@code null}.
* @param structuredType The structured type.
* @throws ODataRenderException If an error occurs while rendering.
* @throws XMLStreamException If an error occurs while rendering.
*/
private void marshallStructured(final Object object, StructuredType structuredType)
throws ODataRenderException, XMLStreamException {
LOG.debug("Start structured value of type: {}", structuredType);
if (object != null) {
visitProperties(entityDataModel, structuredType, property -> {
try {
if (!(property instanceof NavigationProperty)) {
marshallStructuralProperty(object, property);
}
} catch (XMLStreamException e) {
throw new ODataRenderException("Error while writing property: " + property.getName(), e);
}
});
} else {
LOG.debug("Structured value is null");
}
LOG.debug("End structured value of type: {}", structuredType);
}
/**
* Marshall a property of an object.
*
* @param object The object that contains the property. Must not be {@code null}.
* @param property The property.
* @throws ODataRenderException If an error occurs while rendering.
* @throws XMLStreamException If an error occurs while rendering.
*/
private void marshallStructuralProperty(Object object, StructuralProperty property)
throws ODataRenderException, XMLStreamException {
String propertyName = property.getName();
// Get the property value through reflection
Object propertyValue;
Field field = property.getJavaField();
try {
field.setAccessible(true);
propertyValue = field.get(object);
} catch (IllegalAccessException e) {
throw new ODataRenderException("Error getting field value of field: " + field.toGenericString());
}
// Collection properties and non-nullable properties should not be null
if (propertyValue == null) {
if (property.isCollection()) {
throw new ODataRenderException("Collection property has null value: " + property);
} else if (!property.isNullable()) {
throw new ODataRenderException("Non-nullable property has null value: " + property);
}
}
// Check if the property is a collection
final String odataDataNS = nsConfigurationProvider.getOdataDataNs();
final String odataMetadataNs = nsConfigurationProvider.getOdataMetadataNs();
if (property.isCollection()) {
// Get an iterator for the array or collection
Iterator iterator;
if (propertyValue.getClass().isArray()) {
iterator = Arrays.asList((Object[]) propertyValue).iterator();
} else if (Collection.class.isAssignableFrom(propertyValue.getClass())) {
iterator = ((Collection) propertyValue).iterator();
} else {
throw new UnsupportedOperationException("Unsupported collection type: " +
propertyValue.getClass().getName() + " for property: " + propertyName);
}
// Get the OData type of the elements of the collection
Type elementType = entityDataModel.getType(property.getElementTypeName());
if (elementType == null) {
throw new ODataRenderException("OData type not found for elements of property: " + property);
}
LOG.debug("Start collection property: {}", propertyName);
xmlWriter.writeStartElement(ODATA_DATA, propertyName, odataDataNS);
if (elementType.getMetaType().equals(MetaType.PRIMITIVE)) {
xmlWriter.writeAttribute(METADATA, odataMetadataNs, TYPE, HASH + COLLECTION
+ "(" + elementType.getName() + ")");
} else {
xmlWriter.writeAttribute(METADATA, odataMetadataNs, TYPE, HASH + COLLECTION
+ "(" + elementType.getFullyQualifiedName() + ")");
}
while (iterator.hasNext()) {
Object element = iterator.next();
xmlWriter.writeStartElement(METADATA, ELEMENT, odataMetadataNs);
marshall(element, elementType);
xmlWriter.writeEndElement();
}
xmlWriter.writeEndElement();
LOG.debug("End collection property: {}", propertyName);
} else {
// Single value (non-collection) property
LOG.debug("Start property: {}", propertyName);
// Get the OData type of the property
Type propertyType = entityDataModel.getType(property.getTypeName());
if (propertyType == null) {
throw new ODataRenderException("OData type not found for property: " + property);
}
xmlWriter.writeStartElement(ODATA_DATA, propertyName, odataDataNS);
if (propertyValue == null) {
xmlWriter.writeAttribute(METADATA, odataMetadataNs, NULL, "true");
}
switch (propertyType.getMetaType()) {
case PRIMITIVE:
PrimitiveType primitiveType = (PrimitiveType) propertyType;
if (!primitiveType.equals(PrimitiveType.STRING)) {
xmlWriter.writeAttribute(METADATA, odataMetadataNs, TYPE, primitiveType.getName());
}
break;
case COMPLEX:
case ENTITY:
case ENUM:
xmlWriter.writeAttribute(METADATA, odataMetadataNs, TYPE, HASH
+ propertyType.getFullyQualifiedName());
break;
default:
throw new UnsupportedOperationException("Unsupported meta type: " + propertyType.getMetaType());
}
marshall(propertyValue, propertyType);
xmlWriter.writeEndElement();
LOG.debug("End property: {}", propertyName);
}
}
/**
* Marshall an enum value.
*
* @param value The value to marshall. Can be {@code null}.
* @param enumType The OData enum type.
*/
private void marshallEnum(Object value, EnumType enumType) throws XMLStreamException {
LOG.debug("Enum value: {} of type: {}", value, enumType);
xmlWriter.writeCharacters(value.toString());
}
}