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Posted to commits@olingo.apache.org by mi...@apache.org on 2014/06/12 13:01:30 UTC

[3/9] [OLINGO-317] Rename and move of some packages and classes

http://git-wip-us.apache.org/repos/asf/olingo-odata4/blob/b15439ff/lib/commons-core/src/main/java/org/apache/olingo/commons/core/serialization/AtomDeserializer.java
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diff --git a/lib/commons-core/src/main/java/org/apache/olingo/commons/core/serialization/AtomDeserializer.java b/lib/commons-core/src/main/java/org/apache/olingo/commons/core/serialization/AtomDeserializer.java
new file mode 100644
index 0000000..cce71c8
--- /dev/null
+++ b/lib/commons-core/src/main/java/org/apache/olingo/commons/core/serialization/AtomDeserializer.java
@@ -0,0 +1,897 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.apache.olingo.commons.core.serialization;
+
+import java.io.InputStream;
+import java.net.URI;
+import java.text.ParseException;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import javax.xml.namespace.QName;
+import javax.xml.stream.XMLEventReader;
+import javax.xml.stream.XMLInputFactory;
+import javax.xml.stream.XMLStreamException;
+import javax.xml.stream.events.Attribute;
+import javax.xml.stream.events.StartElement;
+import javax.xml.stream.events.XMLEvent;
+
+import org.apache.commons.lang3.StringUtils;
+import org.apache.olingo.commons.api.Constants;
+import org.apache.olingo.commons.api.data.Annotation;
+import org.apache.olingo.commons.api.data.CollectionValue;
+import org.apache.olingo.commons.api.data.DeletedEntity.Reason;
+import org.apache.olingo.commons.api.data.Delta;
+import org.apache.olingo.commons.api.data.Entity;
+import org.apache.olingo.commons.api.data.EntitySet;
+import org.apache.olingo.commons.api.data.Property;
+import org.apache.olingo.commons.api.data.ResWrap;
+import org.apache.olingo.commons.api.data.Valuable;
+import org.apache.olingo.commons.api.data.Value;
+import org.apache.olingo.commons.api.data.v3.LinkCollection;
+import org.apache.olingo.commons.api.domain.ODataError;
+import org.apache.olingo.commons.api.domain.ODataOperation;
+import org.apache.olingo.commons.api.domain.ODataPropertyType;
+import org.apache.olingo.commons.api.edm.EdmPrimitiveTypeKind;
+import org.apache.olingo.commons.api.edm.constants.ODataServiceVersion;
+import org.apache.olingo.commons.api.format.ContentType;
+import org.apache.olingo.commons.api.serialization.ODataDeserializer;
+import org.apache.olingo.commons.api.serialization.ODataDeserializerException;
+import org.apache.olingo.commons.core.data.AbstractODataObject;
+import org.apache.olingo.commons.core.data.AnnotationImpl;
+import org.apache.olingo.commons.core.data.CollectionValueImpl;
+import org.apache.olingo.commons.core.data.ComplexValueImpl;
+import org.apache.olingo.commons.core.data.DeletedEntityImpl;
+import org.apache.olingo.commons.core.data.DeltaLinkImpl;
+import org.apache.olingo.commons.core.data.EntityImpl;
+import org.apache.olingo.commons.core.data.EntitySetImpl;
+import org.apache.olingo.commons.core.data.EnumValueImpl;
+import org.apache.olingo.commons.core.data.GeospatialValueImpl;
+import org.apache.olingo.commons.core.data.LinkImpl;
+import org.apache.olingo.commons.core.data.LinkedComplexValueImpl;
+import org.apache.olingo.commons.core.data.NullValueImpl;
+import org.apache.olingo.commons.core.data.ODataErrorImpl;
+import org.apache.olingo.commons.core.data.PrimitiveValueImpl;
+import org.apache.olingo.commons.core.data.PropertyImpl;
+import org.apache.olingo.commons.core.data.v3.LinkCollectionImpl;
+import org.apache.olingo.commons.core.data.v4.DeltaImpl;
+import org.apache.olingo.commons.core.edm.EdmTypeInfo;
+
+import com.fasterxml.aalto.stax.InputFactoryImpl;
+
+public class AtomDeserializer extends AbstractAtomDealer implements ODataDeserializer {
+
+  protected static final XMLInputFactory FACTORY = new InputFactoryImpl();
+
+  private final AtomGeoValueDeserializer geoDeserializer;
+
+  protected XMLEventReader getReader(final InputStream input) throws XMLStreamException {
+    return FACTORY.createXMLEventReader(input);
+  }
+
+  public AtomDeserializer(final ODataServiceVersion version) {
+    super(version);
+    this.geoDeserializer = new AtomGeoValueDeserializer();
+  }
+
+  private Value fromPrimitive(final XMLEventReader reader, final StartElement start,
+      final EdmTypeInfo typeInfo) throws XMLStreamException {
+
+    Value value = null;
+
+    boolean foundEndProperty = false;
+    while (reader.hasNext() && !foundEndProperty) {
+      final XMLEvent event = reader.nextEvent();
+
+      if (event.isStartElement() && typeInfo != null && typeInfo.getPrimitiveTypeKind().isGeospatial()) {
+        final EdmPrimitiveTypeKind geoType = EdmPrimitiveTypeKind.valueOfFQN(
+            version, typeInfo.getFullQualifiedName().toString());
+        value = new GeospatialValueImpl(this.geoDeserializer.deserialize(reader, event.asStartElement(), geoType));
+      }
+
+      if (event.isCharacters() && !event.asCharacters().isWhiteSpace()
+          && (typeInfo == null || !typeInfo.getPrimitiveTypeKind().isGeospatial())) {
+
+        value = new PrimitiveValueImpl(event.asCharacters().getData());
+      }
+
+      if (event.isEndElement() && start.getName().equals(event.asEndElement().getName())) {
+        foundEndProperty = true;
+      }
+    }
+
+    return value == null ? new PrimitiveValueImpl(StringUtils.EMPTY) : value;
+  }
+
+  private Value fromComplexOrEnum(final XMLEventReader reader, final StartElement start)
+      throws XMLStreamException {
+
+    Value value = null;
+
+    boolean foundEndProperty = false;
+    while (reader.hasNext() && !foundEndProperty) {
+      final XMLEvent event = reader.nextEvent();
+
+      if (event.isStartElement()) {
+        if (value == null) {
+          value = version.compareTo(ODataServiceVersion.V40) < 0
+              ? new ComplexValueImpl()
+              : new LinkedComplexValueImpl();
+        }
+
+        if (Constants.QNAME_ATOM_ELEM_LINK.equals(event.asStartElement().getName())) {
+          final LinkImpl link = new LinkImpl();
+          final Attribute rel = event.asStartElement().getAttributeByName(QName.valueOf(Constants.ATTR_REL));
+          if (rel != null) {
+            link.setRel(rel.getValue());
+          }
+          final Attribute title = event.asStartElement().getAttributeByName(QName.valueOf(Constants.ATTR_TITLE));
+          if (title != null) {
+            link.setTitle(title.getValue());
+          }
+          final Attribute href = event.asStartElement().getAttributeByName(QName.valueOf(Constants.ATTR_HREF));
+          if (href != null) {
+            link.setHref(href.getValue());
+          }
+          final Attribute type = event.asStartElement().getAttributeByName(QName.valueOf(Constants.ATTR_TYPE));
+          if (type != null) {
+            link.setType(type.getValue());
+          }
+
+          if (link.getRel().startsWith(
+              version.getNamespaceMap().get(ODataServiceVersion.NAVIGATION_LINK_REL))) {
+
+            value.asLinkedComplex().getNavigationLinks().add(link);
+            inline(reader, event.asStartElement(), link);
+          } else if (link.getRel().startsWith(
+              version.getNamespaceMap().get(ODataServiceVersion.ASSOCIATION_LINK_REL))) {
+
+            value.asLinkedComplex().getAssociationLinks().add(link);
+          }
+        } else {
+          value.asComplex().get().add(property(reader, event.asStartElement()));
+        }
+      }
+
+      if (event.isCharacters() && !event.asCharacters().isWhiteSpace()) {
+        value = new EnumValueImpl(event.asCharacters().getData());
+      }
+
+      if (event.isEndElement() && start.getName().equals(event.asEndElement().getName())) {
+        foundEndProperty = true;
+      }
+    }
+
+    return value;
+  }
+
+  private CollectionValue fromCollection(final XMLEventReader reader, final StartElement start,
+      final EdmTypeInfo typeInfo) throws XMLStreamException {
+
+    final CollectionValueImpl value = new CollectionValueImpl();
+
+    final EdmTypeInfo type = typeInfo == null
+        ? null
+        : new EdmTypeInfo.Builder().setTypeExpression(typeInfo.getFullQualifiedName().toString()).build();
+
+    boolean foundEndProperty = false;
+    while (reader.hasNext() && !foundEndProperty) {
+      final XMLEvent event = reader.nextEvent();
+
+      if (event.isStartElement()) {
+        switch (guessPropertyType(reader, typeInfo)) {
+        case COMPLEX:
+        case ENUM:
+          value.get().add(fromComplexOrEnum(reader, event.asStartElement()));
+          break;
+
+        case PRIMITIVE:
+          value.get().add(fromPrimitive(reader, event.asStartElement(), type));
+          break;
+
+        default:
+          // do not add null or empty values
+        }
+      }
+
+      if (event.isEndElement() && start.getName().equals(event.asEndElement().getName())) {
+        foundEndProperty = true;
+      }
+    }
+
+    return value;
+  }
+
+  private ODataPropertyType guessPropertyType(final XMLEventReader reader, final EdmTypeInfo typeInfo)
+      throws XMLStreamException {
+
+    XMLEvent child = null;
+    while (reader.hasNext() && child == null) {
+      final XMLEvent event = reader.peek();
+      if (event.isCharacters() && event.asCharacters().isWhiteSpace()) {
+        reader.nextEvent();
+      } else {
+        child = event;
+      }
+    }
+
+    final ODataPropertyType type;
+    if (child == null) {
+      type = typeInfo == null || typeInfo.isPrimitiveType()
+          ? ODataPropertyType.PRIMITIVE
+          : ODataPropertyType.ENUM;
+    } else {
+      if (child.isStartElement()) {
+        if (Constants.NS_GML.equals(child.asStartElement().getName().getNamespaceURI())) {
+          type = ODataPropertyType.PRIMITIVE;
+        } else if (elementQName.equals(child.asStartElement().getName())) {
+          type = ODataPropertyType.COLLECTION;
+        } else {
+          type = ODataPropertyType.COMPLEX;
+        }
+      } else if (child.isCharacters()) {
+        type = typeInfo == null || typeInfo.isPrimitiveType()
+            ? ODataPropertyType.PRIMITIVE
+            : ODataPropertyType.ENUM;
+      } else {
+        type = ODataPropertyType.EMPTY;
+      }
+    }
+
+    return type;
+  }
+
+  private Property property(final XMLEventReader reader, final StartElement start)
+      throws XMLStreamException {
+
+    final PropertyImpl property = new PropertyImpl();
+
+    if (ODataServiceVersion.V40 == version && propertyValueQName.equals(start.getName())) {
+      // retrieve name from context
+      final Attribute context = start.getAttributeByName(contextQName);
+      if (context != null) {
+        property.setName(StringUtils.substringAfterLast(context.getValue(), "/"));
+      }
+    } else {
+      property.setName(start.getName().getLocalPart());
+    }
+
+    valuable(property, reader, start);
+
+    return property;
+  }
+
+  private void valuable(final Valuable valuable, final XMLEventReader reader, final StartElement start)
+      throws XMLStreamException {
+
+    final Attribute nullAttr = start.getAttributeByName(this.nullQName);
+
+    Value value;
+    if (nullAttr == null) {
+      final Attribute typeAttr = start.getAttributeByName(this.typeQName);
+      final String typeAttrValue = typeAttr == null ? null : typeAttr.getValue();
+
+      final EdmTypeInfo typeInfo = StringUtils.isBlank(typeAttrValue)
+          ? null
+          : new EdmTypeInfo.Builder().setTypeExpression(typeAttrValue).build();
+
+      if (typeInfo != null) {
+        valuable.setType(typeInfo.internal());
+      }
+
+      final ODataPropertyType propType = typeInfo == null
+          ? guessPropertyType(reader, typeInfo)
+          : typeInfo.isCollection()
+              ? ODataPropertyType.COLLECTION
+              : typeInfo.isPrimitiveType()
+                  ? ODataPropertyType.PRIMITIVE
+                  : ODataPropertyType.COMPLEX;
+
+      switch (propType) {
+      case COLLECTION:
+        value = fromCollection(reader, start, typeInfo);
+        break;
+
+      case COMPLEX:
+        value = fromComplexOrEnum(reader, start);
+        break;
+
+      case PRIMITIVE:
+        // No type specified? Defaults to Edm.String
+        if (typeInfo == null) {
+          valuable.setType(EdmPrimitiveTypeKind.String.getFullQualifiedName().toString());
+        }
+        value = fromPrimitive(reader, start, typeInfo);
+        break;
+
+      case EMPTY:
+      default:
+        value = new PrimitiveValueImpl(StringUtils.EMPTY);
+      }
+    } else {
+      value = new NullValueImpl();
+    }
+
+    valuable.setValue(value);
+  }
+
+  @Override
+  public ResWrap<Property> toProperty(final InputStream input) throws ODataDeserializerException {
+    try {
+      final XMLEventReader reader = getReader(input);
+      final StartElement start = skipBeforeFirstStartElement(reader);
+      return getContainer(start, property(reader, start));
+    } catch (XMLStreamException e) {
+      throw new ODataDeserializerException(e);
+    }
+  }
+
+  private StartElement skipBeforeFirstStartElement(final XMLEventReader reader) throws XMLStreamException {
+    StartElement startEvent = null;
+    while (reader.hasNext() && startEvent == null) {
+      final XMLEvent event = reader.nextEvent();
+      if (event.isStartElement()) {
+        startEvent = event.asStartElement();
+      }
+    }
+    if (startEvent == null) {
+      throw new IllegalArgumentException("Cannot find any XML start element");
+    }
+
+    return startEvent;
+  }
+
+  private void common(final XMLEventReader reader, final StartElement start,
+      final AbstractODataObject object, final String key) throws XMLStreamException {
+
+    boolean foundEndElement = false;
+    while (reader.hasNext() && !foundEndElement) {
+      final XMLEvent event = reader.nextEvent();
+
+      if (event.isCharacters() && !event.asCharacters().isWhiteSpace()) {
+        try {
+          object.setCommonProperty(key, event.asCharacters().getData());
+        } catch (ParseException e) {
+          throw new XMLStreamException("While parsing Atom entry or feed common elements", e);
+        }
+      }
+
+      if (event.isEndElement() && start.getName().equals(event.asEndElement().getName())) {
+        foundEndElement = true;
+      }
+    }
+  }
+
+  private void inline(final XMLEventReader reader, final StartElement start, final LinkImpl link)
+      throws XMLStreamException {
+
+    boolean foundEndElement = false;
+    while (reader.hasNext() && !foundEndElement) {
+      final XMLEvent event = reader.nextEvent();
+
+      if (event.isStartElement()) {
+        if (inlineQName.equals(event.asStartElement().getName())) {
+          StartElement inline = null;
+          while (reader.hasNext() && inline == null) {
+            final XMLEvent innerEvent = reader.peek();
+            if (innerEvent.isCharacters() && innerEvent.asCharacters().isWhiteSpace()) {
+              reader.nextEvent();
+            } else if (innerEvent.isStartElement()) {
+              inline = innerEvent.asStartElement();
+            }
+          }
+          if (inline != null) {
+            if (Constants.QNAME_ATOM_ELEM_ENTRY.equals(inline.getName())) {
+              link.setInlineEntity(entity(reader, inline));
+            }
+            if (Constants.QNAME_ATOM_ELEM_FEED.equals(inline.getName())) {
+              link.setInlineEntitySet(entitySet(reader, inline));
+            }
+          }
+        } else if (annotationQName.equals(event.asStartElement().getName())) {
+          link.getAnnotations().add(annotation(reader, event.asStartElement()));
+        }
+      }
+
+      if (event.isEndElement() && start.getName().equals(event.asEndElement().getName())) {
+        foundEndElement = true;
+      }
+    }
+  }
+
+  public ResWrap<Delta> delta(final InputStream input) throws XMLStreamException {
+    final XMLEventReader reader = getReader(input);
+    final StartElement start = skipBeforeFirstStartElement(reader);
+    return getContainer(start, delta(reader, start));
+  }
+
+  private Delta delta(final XMLEventReader reader, final StartElement start) throws XMLStreamException {
+    if (!Constants.QNAME_ATOM_ELEM_FEED.equals(start.getName())) {
+      return null;
+    }
+    final DeltaImpl delta = new DeltaImpl();
+    final Attribute xmlBase = start.getAttributeByName(Constants.QNAME_ATTR_XML_BASE);
+    if (xmlBase != null) {
+      delta.setBaseURI(xmlBase.getValue());
+    }
+
+    boolean foundEndFeed = false;
+    while (reader.hasNext() && !foundEndFeed) {
+      final XMLEvent event = reader.nextEvent();
+      if (event.isStartElement()) {
+        if (countQName.equals(event.asStartElement().getName())) {
+          count(reader, event.asStartElement(), delta);
+        } else if (Constants.QNAME_ATOM_ELEM_ID.equals(event.asStartElement().getName())) {
+          common(reader, event.asStartElement(), delta, "id");
+        } else if (Constants.QNAME_ATOM_ELEM_TITLE.equals(event.asStartElement().getName())) {
+          common(reader, event.asStartElement(), delta, "title");
+        } else if (Constants.QNAME_ATOM_ELEM_SUMMARY.equals(event.asStartElement().getName())) {
+          common(reader, event.asStartElement(), delta, "summary");
+        } else if (Constants.QNAME_ATOM_ELEM_UPDATED.equals(event.asStartElement().getName())) {
+          common(reader, event.asStartElement(), delta, "updated");
+        } else if (Constants.QNAME_ATOM_ELEM_LINK.equals(event.asStartElement().getName())) {
+          final Attribute rel = event.asStartElement().getAttributeByName(QName.valueOf(Constants.ATTR_REL));
+          if (rel != null) {
+            if (Constants.NEXT_LINK_REL.equals(rel.getValue())) {
+              final Attribute href = event.asStartElement().getAttributeByName(QName.valueOf(Constants.ATTR_HREF));
+              if (href != null) {
+                delta.setNext(URI.create(href.getValue()));
+              }
+            }
+            if (Constants.DELTA_LINK_REL.equals(rel.getValue())) {
+              final Attribute href = event.asStartElement().getAttributeByName(QName.valueOf(Constants.ATTR_HREF));
+              if (href != null) {
+                delta.setDeltaLink(URI.create(href.getValue()));
+              }
+            }
+          }
+        } else if (Constants.QNAME_ATOM_ELEM_ENTRY.equals(event.asStartElement().getName())) {
+          delta.getEntities().add(entity(reader, event.asStartElement()));
+        } else if (deletedEntryQName.equals(event.asStartElement().getName())) {
+          final DeletedEntityImpl deletedEntity = new DeletedEntityImpl();
+
+          final Attribute ref = event.asStartElement().getAttributeByName(QName.valueOf(Constants.ATTR_REF));
+          if (ref != null) {
+            deletedEntity.setId(URI.create(ref.getValue()));
+          }
+          final Attribute reason = event.asStartElement().getAttributeByName(reasonQName);
+          if (reason != null) {
+            deletedEntity.setReason(Reason.valueOf(reason.getValue()));
+          }
+
+          delta.getDeletedEntities().add(deletedEntity);
+        } else if (linkQName.equals(event.asStartElement().getName())
+            || deletedLinkQName.equals(event.asStartElement().getName())) {
+
+          final DeltaLinkImpl link = new DeltaLinkImpl();
+
+          final Attribute source = event.asStartElement().getAttributeByName(QName.valueOf(Constants.ATTR_SOURCE));
+          if (source != null) {
+            link.setSource(URI.create(source.getValue()));
+          }
+          final Attribute relationship =
+              event.asStartElement().getAttributeByName(QName.valueOf(Constants.ATTR_RELATIONSHIP));
+          if (relationship != null) {
+            link.setRelationship(relationship.getValue());
+          }
+          final Attribute target = event.asStartElement().getAttributeByName(QName.valueOf(Constants.ATTR_TARGET));
+          if (target != null) {
+            link.setTarget(URI.create(target.getValue()));
+          }
+
+          if (linkQName.equals(event.asStartElement().getName())) {
+            delta.getAddedLinks().add(link);
+          } else {
+            delta.getDeletedLinks().add(link);
+          }
+        }
+      }
+
+      if (event.isEndElement() && start.getName().equals(event.asEndElement().getName())) {
+        foundEndFeed = true;
+      }
+    }
+
+    return delta;
+  }
+
+  public ResWrap<LinkCollection> linkCollection(final InputStream input) throws XMLStreamException {
+    final XMLEventReader reader = getReader(input);
+    final StartElement start = skipBeforeFirstStartElement(reader);
+    return getContainer(start, linkCollection(reader));
+  }
+
+  private LinkCollection linkCollection(final XMLEventReader reader) throws XMLStreamException {
+
+    final LinkCollectionImpl linkCollection = new LinkCollectionImpl();
+
+    boolean isURI = false;
+    boolean isNext = false;
+    while (reader.hasNext()) {
+      final XMLEvent event = reader.nextEvent();
+      if (event.isStartElement()) {
+        isURI = uriQName.equals(event.asStartElement().getName());
+        isNext = nextQName.equals(event.asStartElement().getName());
+      }
+
+      if (event.isCharacters() && !event.asCharacters().isWhiteSpace()) {
+        if (isURI) {
+          linkCollection.getLinks().add(URI.create(event.asCharacters().getData()));
+          isURI = false;
+        } else if (isNext) {
+          linkCollection.setNext(URI.create(event.asCharacters().getData()));
+          isNext = false;
+        }
+      }
+    }
+
+    return linkCollection;
+  }
+
+  private void properties(final XMLEventReader reader, final StartElement start, final EntityImpl entity)
+      throws XMLStreamException {
+
+    final Map<String, List<Annotation>> annotations = new HashMap<String, List<Annotation>>();
+
+    boolean foundEndProperties = false;
+    while (reader.hasNext() && !foundEndProperties) {
+      final XMLEvent event = reader.nextEvent();
+
+      if (event.isStartElement()) {
+        if (annotationQName.equals(event.asStartElement().getName())) {
+          final String target = event.asStartElement().
+              getAttributeByName(QName.valueOf(Constants.ATTR_TARGET)).getValue();
+          if (!annotations.containsKey(target)) {
+            annotations.put(target, new ArrayList<Annotation>());
+          }
+          annotations.get(target).add(annotation(reader, event.asStartElement()));
+        } else {
+          entity.getProperties().add(property(reader, event.asStartElement()));
+        }
+      }
+
+      if (event.isEndElement() && start.getName().equals(event.asEndElement().getName())) {
+        foundEndProperties = true;
+      }
+    }
+
+    for (Property property : entity.getProperties()) {
+      if (annotations.containsKey(property.getName())) {
+        property.getAnnotations().addAll(annotations.get(property.getName()));
+      }
+    }
+  }
+
+  private Annotation annotation(final XMLEventReader reader, final StartElement start)
+      throws XMLStreamException {
+
+    final Annotation annotation = new AnnotationImpl();
+
+    annotation.setTerm(start.getAttributeByName(QName.valueOf(Constants.ATOM_ATTR_TERM)).getValue());
+    valuable(annotation, reader, start);
+
+    return annotation;
+  }
+
+  private EntityImpl entityRef(final StartElement start) throws XMLStreamException {
+    final EntityImpl entity = new EntityImpl();
+
+    final Attribute entityRefId = start.getAttributeByName(Constants.QNAME_ATOM_ATTR_ID);
+    if (entityRefId != null) {
+      entity.setId(URI.create(entityRefId.getValue()));
+    }
+
+    return entity;
+  }
+
+  private Entity entity(final XMLEventReader reader, final StartElement start) throws XMLStreamException {
+    final EntityImpl entity;
+    if (entryRefQName.equals(start.getName())) {
+      entity = entityRef(start);
+    } else if (Constants.QNAME_ATOM_ELEM_ENTRY.equals(start.getName())) {
+      entity = new EntityImpl();
+      final Attribute xmlBase = start.getAttributeByName(Constants.QNAME_ATTR_XML_BASE);
+      if (xmlBase != null) {
+        entity.setBaseURI(xmlBase.getValue());
+      }
+
+      final Attribute etag = start.getAttributeByName(etagQName);
+      if (etag != null) {
+        entity.setETag(etag.getValue());
+      }
+
+      boolean foundEndEntry = false;
+      while (reader.hasNext() && !foundEndEntry) {
+        final XMLEvent event = reader.nextEvent();
+
+        if (event.isStartElement()) {
+          if (Constants.QNAME_ATOM_ELEM_ID.equals(event.asStartElement().getName())) {
+            common(reader, event.asStartElement(), entity, "id");
+          } else if (Constants.QNAME_ATOM_ELEM_TITLE.equals(event.asStartElement().getName())) {
+            common(reader, event.asStartElement(), entity, "title");
+          } else if (Constants.QNAME_ATOM_ELEM_SUMMARY.equals(event.asStartElement().getName())) {
+            common(reader, event.asStartElement(), entity, "summary");
+          } else if (Constants.QNAME_ATOM_ELEM_UPDATED.equals(event.asStartElement().getName())) {
+            common(reader, event.asStartElement(), entity, "updated");
+          } else if (Constants.QNAME_ATOM_ELEM_CATEGORY.equals(event.asStartElement().getName())) {
+            final Attribute term = event.asStartElement().getAttributeByName(QName.valueOf(Constants.ATOM_ATTR_TERM));
+            if (term != null) {
+              entity.setType(new EdmTypeInfo.Builder().setTypeExpression(term.getValue()).build().internal());
+            }
+          } else if (Constants.QNAME_ATOM_ELEM_LINK.equals(event.asStartElement().getName())) {
+            final LinkImpl link = new LinkImpl();
+            final Attribute rel = event.asStartElement().getAttributeByName(QName.valueOf(Constants.ATTR_REL));
+            if (rel != null) {
+              link.setRel(rel.getValue());
+            }
+            final Attribute title = event.asStartElement().getAttributeByName(QName.valueOf(Constants.ATTR_TITLE));
+            if (title != null) {
+              link.setTitle(title.getValue());
+            }
+            final Attribute href = event.asStartElement().getAttributeByName(QName.valueOf(Constants.ATTR_HREF));
+            if (href != null) {
+              link.setHref(href.getValue());
+            }
+            final Attribute type = event.asStartElement().getAttributeByName(QName.valueOf(Constants.ATTR_TYPE));
+            if (type != null) {
+              link.setType(type.getValue());
+            }
+
+            if (Constants.SELF_LINK_REL.equals(link.getRel())) {
+              entity.setSelfLink(link);
+            } else if (Constants.EDIT_LINK_REL.equals(link.getRel())) {
+              entity.setEditLink(link);
+            } else if (Constants.EDITMEDIA_LINK_REL.equals(link.getRel())) {
+              final Attribute mediaETag = event.asStartElement().getAttributeByName(etagQName);
+              if (mediaETag != null) {
+                entity.setMediaETag(mediaETag.getValue());
+              }
+            } else if (link.getRel().startsWith(
+                version.getNamespaceMap().get(ODataServiceVersion.NAVIGATION_LINK_REL))) {
+
+              entity.getNavigationLinks().add(link);
+              inline(reader, event.asStartElement(), link);
+            } else if (link.getRel().startsWith(
+                version.getNamespaceMap().get(ODataServiceVersion.ASSOCIATION_LINK_REL))) {
+
+              entity.getAssociationLinks().add(link);
+            } else if (link.getRel().startsWith(
+                version.getNamespaceMap().get(ODataServiceVersion.MEDIA_EDIT_LINK_REL))) {
+
+              final Attribute metag = event.asStartElement().getAttributeByName(etagQName);
+              if (metag != null) {
+                link.setMediaETag(metag.getValue());
+              }
+              entity.getMediaEditLinks().add(link);
+            }
+          } else if (actionQName.equals(event.asStartElement().getName())) {
+            final ODataOperation operation = new ODataOperation();
+            final Attribute metadata =
+                event.asStartElement().getAttributeByName(QName.valueOf(Constants.ATTR_METADATA));
+            if (metadata != null) {
+              operation.setMetadataAnchor(metadata.getValue());
+            }
+            final Attribute title = event.asStartElement().getAttributeByName(QName.valueOf(Constants.ATTR_TITLE));
+            if (title != null) {
+              operation.setTitle(title.getValue());
+            }
+            final Attribute target = event.asStartElement().getAttributeByName(QName.valueOf(Constants.ATTR_TARGET));
+            if (target != null) {
+              operation.setTarget(URI.create(target.getValue()));
+            }
+
+            entity.getOperations().add(operation);
+          } else if (Constants.QNAME_ATOM_ELEM_CONTENT.equals(event.asStartElement().getName())) {
+            final Attribute type = event.asStartElement().getAttributeByName(QName.valueOf(Constants.ATTR_TYPE));
+            if (type == null || ContentType.APPLICATION_XML.equals(type.getValue())) {
+              properties(reader, skipBeforeFirstStartElement(reader), entity);
+            } else {
+              entity.setMediaContentType(type.getValue());
+              final Attribute src = event.asStartElement().getAttributeByName(QName.valueOf(Constants.ATOM_ATTR_SRC));
+              if (src != null) {
+                entity.setMediaContentSource(URI.create(src.getValue()));
+              }
+            }
+          } else if (propertiesQName.equals(event.asStartElement().getName())) {
+            properties(reader, event.asStartElement(), entity);
+          } else if (annotationQName.equals(event.asStartElement().getName())) {
+            entity.getAnnotations().add(annotation(reader, event.asStartElement()));
+          }
+        }
+
+        if (event.isEndElement() && start.getName().equals(event.asEndElement().getName())) {
+          foundEndEntry = true;
+        }
+      }
+    } else {
+      entity = null;
+    }
+
+    return entity;
+  }
+
+  @Override
+  public ResWrap<Entity> toEntity(final InputStream input) throws ODataDeserializerException {
+    try {
+      final XMLEventReader reader = getReader(input);
+      final StartElement start = skipBeforeFirstStartElement(reader);
+      return getContainer(start, entity(reader, start));
+    } catch (XMLStreamException e) {
+      throw new ODataDeserializerException(e);
+    }
+  }
+
+  private void count(final XMLEventReader reader, final StartElement start, final EntitySet entitySet)
+      throws XMLStreamException {
+
+    boolean foundEndElement = false;
+    while (reader.hasNext() && !foundEndElement) {
+      final XMLEvent event = reader.nextEvent();
+
+      if (event.isCharacters() && !event.asCharacters().isWhiteSpace()) {
+        entitySet.setCount(Integer.valueOf(event.asCharacters().getData()));
+      }
+
+      if (event.isEndElement() && start.getName().equals(event.asEndElement().getName())) {
+        foundEndElement = true;
+      }
+    }
+  }
+
+  private EntitySet entitySet(final XMLEventReader reader, final StartElement start) throws XMLStreamException {
+    if (!Constants.QNAME_ATOM_ELEM_FEED.equals(start.getName())) {
+      return null;
+    }
+    final EntitySetImpl entitySet = new EntitySetImpl();
+    final Attribute xmlBase = start.getAttributeByName(Constants.QNAME_ATTR_XML_BASE);
+    if (xmlBase != null) {
+      entitySet.setBaseURI(xmlBase.getValue());
+    }
+
+    boolean foundEndFeed = false;
+    while (reader.hasNext() && !foundEndFeed) {
+      final XMLEvent event = reader.nextEvent();
+      if (event.isStartElement()) {
+        if (countQName.equals(event.asStartElement().getName())) {
+          count(reader, event.asStartElement(), entitySet);
+        } else if (Constants.QNAME_ATOM_ELEM_ID.equals(event.asStartElement().getName())) {
+          common(reader, event.asStartElement(), entitySet, "id");
+        } else if (Constants.QNAME_ATOM_ELEM_TITLE.equals(event.asStartElement().getName())) {
+          common(reader, event.asStartElement(), entitySet, "title");
+        } else if (Constants.QNAME_ATOM_ELEM_SUMMARY.equals(event.asStartElement().getName())) {
+          common(reader, event.asStartElement(), entitySet, "summary");
+        } else if (Constants.QNAME_ATOM_ELEM_UPDATED.equals(event.asStartElement().getName())) {
+          common(reader, event.asStartElement(), entitySet, "updated");
+        } else if (Constants.QNAME_ATOM_ELEM_LINK.equals(event.asStartElement().getName())) {
+          final Attribute rel = event.asStartElement().getAttributeByName(QName.valueOf(Constants.ATTR_REL));
+          if (rel != null) {
+            if (Constants.NEXT_LINK_REL.equals(rel.getValue())) {
+              final Attribute href = event.asStartElement().getAttributeByName(QName.valueOf(Constants.ATTR_HREF));
+              if (href != null) {
+                entitySet.setNext(URI.create(href.getValue()));
+              }
+            }
+            if (Constants.DELTA_LINK_REL.equals(rel.getValue())) {
+              final Attribute href = event.asStartElement().getAttributeByName(QName.valueOf(Constants.ATTR_HREF));
+              if (href != null) {
+                entitySet.setDeltaLink(URI.create(href.getValue()));
+              }
+            }
+          }
+        } else if (Constants.QNAME_ATOM_ELEM_ENTRY.equals(event.asStartElement().getName())) {
+          entitySet.getEntities().add(entity(reader, event.asStartElement()));
+        } else if (entryRefQName.equals(event.asStartElement().getName())) {
+          entitySet.getEntities().add(entityRef(event.asStartElement()));
+        } else if (annotationQName.equals(event.asStartElement().getName())) {
+          entitySet.getAnnotations().add(annotation(reader, event.asStartElement()));
+        }
+      }
+
+      if (event.isEndElement() && start.getName().equals(event.asEndElement().getName())) {
+        foundEndFeed = true;
+      }
+    }
+
+    return entitySet;
+  }
+
+  @Override
+  public ResWrap<EntitySet> toEntitySet(final InputStream input) throws ODataDeserializerException {
+    try {
+      final XMLEventReader reader = getReader(input);
+      final StartElement start = skipBeforeFirstStartElement(reader);
+      return getContainer(start, entitySet(reader, start));
+    } catch (XMLStreamException e) {
+      throw new ODataDeserializerException(e);
+    }
+  }
+
+  private ODataError error(final XMLEventReader reader, final StartElement start) throws XMLStreamException {
+    final ODataErrorImpl error = new ODataErrorImpl();
+
+    boolean setCode = false;
+    boolean codeSet = false;
+    boolean setMessage = false;
+    boolean messageSet = false;
+    boolean setTarget = false;
+    boolean targetSet = false;
+
+    boolean foundEndElement = false;
+    while (reader.hasNext() && !foundEndElement) {
+      final XMLEvent event = reader.nextEvent();
+
+      if (event.isStartElement()) {
+        if (errorCodeQName.equals(event.asStartElement().getName())) {
+          setCode = true;
+        } else if (errorMessageQName.equals(event.asStartElement().getName())) {
+          setMessage = true;
+        } else if (errorTargetQName.equals(event.asStartElement().getName())) {
+          setTarget = true;
+        }
+      }
+
+      if (event.isCharacters() && !event.asCharacters().isWhiteSpace()) {
+        if (setCode && !codeSet) {
+          error.setCode(event.asCharacters().getData());
+          setCode = false;
+          codeSet = true;
+        }
+        if (setMessage && !messageSet) {
+          error.setMessage(event.asCharacters().getData());
+          setMessage = false;
+          messageSet = true;
+        }
+        if (setTarget && !targetSet) {
+          error.setTarget(event.asCharacters().getData());
+          setTarget = false;
+          targetSet = true;
+        }
+      }
+
+      if (event.isEndElement() && start.getName().equals(event.asEndElement().getName())) {
+        foundEndElement = true;
+      }
+    }
+
+    return error;
+  }
+
+  @Override
+  public ODataError toError(final InputStream input) throws ODataDeserializerException {
+    try {
+      final XMLEventReader reader = getReader(input);
+      final StartElement start = skipBeforeFirstStartElement(reader);
+      return error(reader, start);
+    } catch (XMLStreamException e) {
+      throw new ODataDeserializerException(e);
+    }
+  }
+
+  private <T> ResWrap<T> getContainer(final StartElement start, final T object) {
+    final Attribute context = start.getAttributeByName(contextQName);
+    final Attribute metadataETag = start.getAttributeByName(metadataEtagQName);
+
+    return new ResWrap<T>(
+        context == null ? null : URI.create(context.getValue()),
+        metadataETag == null ? null : metadataETag.getValue(),
+        object);
+  }
+}

http://git-wip-us.apache.org/repos/asf/olingo-odata4/blob/b15439ff/lib/commons-core/src/main/java/org/apache/olingo/commons/core/serialization/AtomGeoValueDeserializer.java
----------------------------------------------------------------------
diff --git a/lib/commons-core/src/main/java/org/apache/olingo/commons/core/serialization/AtomGeoValueDeserializer.java b/lib/commons-core/src/main/java/org/apache/olingo/commons/core/serialization/AtomGeoValueDeserializer.java
new file mode 100644
index 0000000..0136406
--- /dev/null
+++ b/lib/commons-core/src/main/java/org/apache/olingo/commons/core/serialization/AtomGeoValueDeserializer.java
@@ -0,0 +1,267 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.apache.olingo.commons.core.serialization;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import javax.xml.stream.XMLEventReader;
+import javax.xml.stream.XMLStreamException;
+import javax.xml.stream.events.Attribute;
+import javax.xml.stream.events.StartElement;
+import javax.xml.stream.events.XMLEvent;
+import org.apache.commons.lang3.StringUtils;
+import org.apache.olingo.commons.api.Constants;
+import org.apache.olingo.commons.api.data.GeoUtils;
+import org.apache.olingo.commons.api.edm.EdmPrimitiveTypeException;
+import org.apache.olingo.commons.api.edm.EdmPrimitiveTypeKind;
+import org.apache.olingo.commons.api.edm.geo.Geospatial;
+import org.apache.olingo.commons.api.edm.geo.GeospatialCollection;
+import org.apache.olingo.commons.api.edm.geo.LineString;
+import org.apache.olingo.commons.api.edm.geo.MultiLineString;
+import org.apache.olingo.commons.api.edm.geo.MultiPoint;
+import org.apache.olingo.commons.api.edm.geo.MultiPolygon;
+import org.apache.olingo.commons.api.edm.geo.Point;
+import org.apache.olingo.commons.api.edm.geo.Polygon;
+import org.apache.olingo.commons.api.edm.geo.SRID;
+import org.apache.olingo.commons.core.edm.primitivetype.EdmDouble;
+
+class AtomGeoValueDeserializer {
+
+  private List<Point> points(final XMLEventReader reader, final StartElement start,
+          final EdmPrimitiveTypeKind type, final SRID srid) throws XMLStreamException {
+
+    final List<Point> result = new ArrayList<Point>();
+
+    boolean foundEndProperty = false;
+    while (reader.hasNext() && !foundEndProperty) {
+      final XMLEvent event = reader.nextEvent();
+
+      if (event.isCharacters() && !event.asCharacters().isWhiteSpace()) {
+        final String[] pointInfo = event.asCharacters().getData().split(" ");
+
+        final Point point = new Point(GeoUtils.getDimension(type), srid);
+        try {
+          point.setX(EdmDouble.getInstance().valueOfString(pointInfo[0], null, null,
+                  Constants.DEFAULT_PRECISION, Constants.DEFAULT_SCALE, null, Double.class));
+          point.setY(EdmDouble.getInstance().valueOfString(pointInfo[1], null, null,
+                  Constants.DEFAULT_PRECISION, Constants.DEFAULT_SCALE, null, Double.class));
+        } catch (EdmPrimitiveTypeException e) {
+          throw new XMLStreamException("While deserializing point coordinates as double", e);
+        }
+        result.add(point);
+      }
+
+      if (event.isEndElement() && start.getName().equals(event.asEndElement().getName())) {
+        foundEndProperty = true;
+      }
+    }
+
+    // handles bad input, e.g. things like <gml:pos/>
+    if (result.isEmpty()) {
+      result.add(new Point(GeoUtils.getDimension(type), srid));
+    }
+
+    return result;
+  }
+
+  private MultiPoint multipoint(final XMLEventReader reader, final StartElement start,
+          final EdmPrimitiveTypeKind type, final SRID srid) throws XMLStreamException {
+
+    List<Point> points = Collections.<Point>emptyList();
+
+    boolean foundEndProperty = false;
+    while (reader.hasNext() && !foundEndProperty) {
+      final XMLEvent event = reader.nextEvent();
+
+      if (event.isStartElement() && event.asStartElement().getName().equals(Constants.QNAME_POINTMEMBERS)) {
+        points = points(reader, event.asStartElement(), type, null);
+      }
+
+      if (event.isEndElement() && start.getName().equals(event.asEndElement().getName())) {
+        foundEndProperty = true;
+      }
+    }
+
+    return new MultiPoint(GeoUtils.getDimension(type), srid, points);
+  }
+
+  private LineString lineString(final XMLEventReader reader, final StartElement start,
+          final EdmPrimitiveTypeKind type, final SRID srid) throws XMLStreamException {
+
+    return new LineString(GeoUtils.getDimension(type), srid, points(reader, start, type, null));
+  }
+
+  private Polygon polygon(final XMLEventReader reader, final StartElement start,
+          final EdmPrimitiveTypeKind type, final SRID srid) throws XMLStreamException {
+
+    List<Point> extPoints = null;
+    List<Point> intPoints = null;
+
+    boolean foundEndProperty = false;
+    while (reader.hasNext() && !foundEndProperty) {
+      final XMLEvent event = reader.nextEvent();
+
+      if (event.isStartElement()) {
+        if (event.asStartElement().getName().equals(Constants.QNAME_POLYGON_EXTERIOR)) {
+          extPoints = points(reader, event.asStartElement(), type, null);
+        }
+        if (event.asStartElement().getName().equals(Constants.QNAME_POLYGON_INTERIOR)) {
+          intPoints = points(reader, event.asStartElement(), type, null);
+        }
+      }
+
+      if (event.isEndElement() && start.getName().equals(event.asEndElement().getName())) {
+        foundEndProperty = true;
+      }
+    }
+
+    return new Polygon(GeoUtils.getDimension(type), srid, intPoints, extPoints);
+  }
+
+  private MultiLineString multiLineString(final XMLEventReader reader, final StartElement start,
+          final EdmPrimitiveTypeKind type, final SRID srid) throws XMLStreamException {
+
+    final List<LineString> lineStrings = new ArrayList<LineString>();
+
+    boolean foundEndProperty = false;
+    while (reader.hasNext() && !foundEndProperty) {
+      final XMLEvent event = reader.nextEvent();
+
+      if (event.isStartElement() && event.asStartElement().getName().equals(Constants.QNAME_LINESTRING)) {
+        lineStrings.add(lineString(reader, event.asStartElement(), type, null));
+      }
+
+      if (event.isEndElement() && start.getName().equals(event.asEndElement().getName())) {
+        foundEndProperty = true;
+      }
+    }
+
+    return new MultiLineString(GeoUtils.getDimension(type), srid, lineStrings);
+  }
+
+  private MultiPolygon multiPolygon(final XMLEventReader reader, final StartElement start,
+          final EdmPrimitiveTypeKind type, final SRID srid) throws XMLStreamException {
+
+    final List<Polygon> polygons = new ArrayList<Polygon>();
+
+    boolean foundEndProperty = false;
+    while (reader.hasNext() && !foundEndProperty) {
+      final XMLEvent event = reader.nextEvent();
+
+      if (event.isStartElement() && event.asStartElement().getName().equals(Constants.QNAME_POLYGON)) {
+        polygons.add(polygon(reader, event.asStartElement(), type, null));
+      }
+
+      if (event.isEndElement() && start.getName().equals(event.asEndElement().getName())) {
+        foundEndProperty = true;
+      }
+    }
+
+    return new MultiPolygon(GeoUtils.getDimension(type), srid, polygons);
+  }
+
+  private GeospatialCollection collection(final XMLEventReader reader, final StartElement start,
+          final EdmPrimitiveTypeKind type, final SRID srid) throws XMLStreamException {
+
+    final List<Geospatial> geospatials = new ArrayList<Geospatial>();
+
+    boolean foundEndCollection = false;
+    while (reader.hasNext() && !foundEndCollection) {
+      final XMLEvent event = reader.nextEvent();
+
+      if (event.isStartElement() && event.asStartElement().getName().equals(Constants.QNAME_GEOMEMBERS)) {
+        boolean foundEndMembers = false;
+        while (reader.hasNext() && !foundEndMembers) {
+          final XMLEvent subevent = reader.nextEvent();
+
+          if (subevent.isStartElement()) {
+            geospatials.add(deserialize(reader, subevent.asStartElement(),
+                    GeoUtils.getType(GeoUtils.getDimension(type), subevent.asStartElement().getName().getLocalPart())));
+          }
+
+          if (subevent.isEndElement() && Constants.QNAME_GEOMEMBERS.equals(subevent.asEndElement().getName())) {
+            foundEndMembers = true;
+          }
+        }
+      }
+
+      if (event.isEndElement() && start.getName().equals(event.asEndElement().getName())) {
+        foundEndCollection = true;
+      }
+    }
+
+    return new GeospatialCollection(GeoUtils.getDimension(type), srid, geospatials);
+  }
+
+  public Geospatial deserialize(final XMLEventReader reader, final StartElement start,
+          final EdmPrimitiveTypeKind type) throws XMLStreamException {
+
+    SRID srid = null;
+    final Attribute srsName = start.getAttributeByName(Constants.QNAME_ATTR_SRSNAME);
+    if (srsName != null) {
+      srid = SRID.valueOf(StringUtils.substringAfterLast(srsName.getValue(), "/"));
+    }
+
+    Geospatial value;
+
+    switch (type) {
+      case GeographyPoint:
+      case GeometryPoint:
+        value = points(reader, start, type, srid).get(0);
+        break;
+
+      case GeographyMultiPoint:
+      case GeometryMultiPoint:
+        value = multipoint(reader, start, type, srid);
+        break;
+
+      case GeographyLineString:
+      case GeometryLineString:
+        value = lineString(reader, start, type, srid);
+        break;
+
+      case GeographyMultiLineString:
+      case GeometryMultiLineString:
+        value = multiLineString(reader, start, type, srid);
+        break;
+
+      case GeographyPolygon:
+      case GeometryPolygon:
+        value = polygon(reader, start, type, srid);
+        break;
+
+      case GeographyMultiPolygon:
+      case GeometryMultiPolygon:
+        value = multiPolygon(reader, start, type, srid);
+        break;
+
+      case GeographyCollection:
+      case GeometryCollection:
+        value = collection(reader, start, type, srid);
+        break;
+
+      default:
+        value = null;
+    }
+
+    return value;
+  }
+
+}

http://git-wip-us.apache.org/repos/asf/olingo-odata4/blob/b15439ff/lib/commons-core/src/main/java/org/apache/olingo/commons/core/serialization/AtomGeoValueSerializer.java
----------------------------------------------------------------------
diff --git a/lib/commons-core/src/main/java/org/apache/olingo/commons/core/serialization/AtomGeoValueSerializer.java b/lib/commons-core/src/main/java/org/apache/olingo/commons/core/serialization/AtomGeoValueSerializer.java
new file mode 100644
index 0000000..8f913a0
--- /dev/null
+++ b/lib/commons-core/src/main/java/org/apache/olingo/commons/core/serialization/AtomGeoValueSerializer.java
@@ -0,0 +1,221 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.apache.olingo.commons.core.serialization;
+
+import java.util.Collections;
+import java.util.Iterator;
+import javax.xml.stream.XMLStreamException;
+import javax.xml.stream.XMLStreamWriter;
+import org.apache.olingo.commons.api.Constants;
+import org.apache.olingo.commons.api.edm.EdmPrimitiveTypeException;
+import org.apache.olingo.commons.api.edm.geo.Geospatial;
+import org.apache.olingo.commons.api.edm.geo.GeospatialCollection;
+import org.apache.olingo.commons.api.edm.geo.LineString;
+import org.apache.olingo.commons.api.edm.geo.MultiLineString;
+import org.apache.olingo.commons.api.edm.geo.MultiPoint;
+import org.apache.olingo.commons.api.edm.geo.MultiPolygon;
+import org.apache.olingo.commons.api.edm.geo.Point;
+import org.apache.olingo.commons.api.edm.geo.Polygon;
+import org.apache.olingo.commons.core.edm.primitivetype.EdmDouble;
+
+class AtomGeoValueSerializer {
+
+  private void points(final XMLStreamWriter writer, final Iterator<Point> itor, final boolean wrap)
+          throws XMLStreamException {
+
+    while (itor.hasNext()) {
+      final Point point = itor.next();
+
+      if (wrap) {
+        writer.writeStartElement(Constants.PREFIX_GML, Constants.ELEM_POINT, Constants.NS_GML);
+      }
+
+      writer.writeStartElement(Constants.PREFIX_GML, Constants.ELEM_POS, Constants.NS_GML);
+      try {
+        writer.writeCharacters(EdmDouble.getInstance().valueToString(point.getX(), null, null,
+                Constants.DEFAULT_PRECISION, Constants.DEFAULT_SCALE, null)
+                + " "
+                + EdmDouble.getInstance().valueToString(point.getY(), null, null,
+                        Constants.DEFAULT_PRECISION, Constants.DEFAULT_SCALE, null));
+      } catch (EdmPrimitiveTypeException e) {
+        throw new XMLStreamException("While serializing point coordinates as double", e);
+      }
+      writer.writeEndElement();
+
+      if (wrap) {
+        writer.writeEndElement();
+      }
+    }
+  }
+
+  private void lineStrings(final XMLStreamWriter writer, final Iterator<LineString> itor, final boolean wrap)
+          throws XMLStreamException {
+
+    while (itor.hasNext()) {
+      final LineString lineString = itor.next();
+
+      if (wrap) {
+        writer.writeStartElement(Constants.PREFIX_GML, Constants.ELEM_LINESTRING, Constants.NS_GML);
+      }
+
+      points(writer, lineString.iterator(), false);
+
+      if (wrap) {
+        writer.writeEndElement();
+      }
+    }
+  }
+
+  private void polygons(final XMLStreamWriter writer, final Iterator<Polygon> itor, final boolean wrap)
+          throws XMLStreamException {
+
+    while (itor.hasNext()) {
+      final Polygon polygon = itor.next();
+
+      if (wrap) {
+        writer.writeStartElement(Constants.PREFIX_GML, Constants.ELEM_POLYGON, Constants.NS_GML);
+      }
+
+      if (!polygon.getExterior().isEmpty()) {
+        writer.writeStartElement(Constants.PREFIX_GML, Constants.ELEM_POLYGON_EXTERIOR, Constants.NS_GML);
+        writer.writeStartElement(Constants.PREFIX_GML, Constants.ELEM_POLYGON_LINEARRING, Constants.NS_GML);
+
+        points(writer, polygon.getExterior().iterator(), false);
+
+        writer.writeEndElement();
+        writer.writeEndElement();
+      }
+      if (!polygon.getInterior().isEmpty()) {
+        writer.writeStartElement(Constants.PREFIX_GML, Constants.ELEM_POLYGON_INTERIOR, Constants.NS_GML);
+        writer.writeStartElement(Constants.PREFIX_GML, Constants.ELEM_POLYGON_LINEARRING, Constants.NS_GML);
+
+        points(writer, polygon.getInterior().iterator(), false);
+
+        writer.writeEndElement();
+        writer.writeEndElement();
+      }
+
+      if (wrap) {
+        writer.writeEndElement();
+      }
+    }
+  }
+
+  private void writeSrsName(final XMLStreamWriter writer, final Geospatial value) throws XMLStreamException {
+    if (value.getSrid() != null && value.getSrid().isNotDefault()) {
+      writer.writeAttribute(Constants.PREFIX_GML, Constants.NS_GML, Constants.ATTR_SRSNAME,
+              Constants.SRS_URLPREFIX + value.getSrid().toString());
+    }
+  }
+
+  public void serialize(final XMLStreamWriter writer, final Geospatial value) throws XMLStreamException {
+    switch (value.getEdmPrimitiveTypeKind()) {
+      case GeographyPoint:
+      case GeometryPoint:
+        writer.writeStartElement(Constants.PREFIX_GML, Constants.ELEM_POINT, Constants.NS_GML);
+        writeSrsName(writer, value);
+
+        points(writer, Collections.singleton((Point) value).iterator(), false);
+
+        writer.writeEndElement();
+        break;
+
+      case GeometryMultiPoint:
+      case GeographyMultiPoint:
+        writer.writeStartElement(Constants.PREFIX_GML, Constants.ELEM_MULTIPOINT, Constants.NS_GML);
+        writeSrsName(writer, value);
+
+        if (!((MultiPoint) value).isEmpty()) {
+          writer.writeStartElement(Constants.PREFIX_GML, Constants.ELEM_POINTMEMBERS, Constants.NS_GML);
+          points(writer, ((MultiPoint) value).iterator(), true);
+          writer.writeEndElement();
+        }
+
+        writer.writeEndElement();
+        break;
+
+      case GeometryLineString:
+      case GeographyLineString:
+        writer.writeStartElement(Constants.PREFIX_GML, Constants.ELEM_LINESTRING, Constants.NS_GML);
+        writeSrsName(writer, value);
+
+        lineStrings(writer, Collections.singleton((LineString) value).iterator(), false);
+
+        writer.writeEndElement();
+        break;
+
+      case GeometryMultiLineString:
+      case GeographyMultiLineString:
+        writer.writeStartElement(Constants.PREFIX_GML, Constants.ELEM_MULTILINESTRING, Constants.NS_GML);
+        writeSrsName(writer, value);
+
+        if (!((MultiLineString) value).isEmpty()) {
+          writer.writeStartElement(Constants.PREFIX_GML, Constants.ELEM_LINESTRINGMEMBERS, Constants.NS_GML);
+          lineStrings(writer, ((MultiLineString) value).iterator(), true);
+          writer.writeEndElement();
+        }
+
+        writer.writeEndElement();
+        break;
+
+      case GeographyPolygon:
+      case GeometryPolygon:
+        writer.writeStartElement(Constants.PREFIX_GML, Constants.ELEM_POLYGON, Constants.NS_GML);
+        writeSrsName(writer, value);
+
+        polygons(writer, Collections.singleton(((Polygon) value)).iterator(), false);
+
+        writer.writeEndElement();
+        break;
+
+      case GeographyMultiPolygon:
+      case GeometryMultiPolygon:
+        writer.writeStartElement(Constants.PREFIX_GML, Constants.ELEM_MULTIPOLYGON, Constants.NS_GML);
+        writeSrsName(writer, value);
+
+        if (!((MultiPolygon) value).isEmpty()) {
+          writer.writeStartElement(Constants.PREFIX_GML, Constants.ELEM_SURFACEMEMBERS, Constants.NS_GML);
+          polygons(writer, ((MultiPolygon) value).iterator(), true);
+          writer.writeEndElement();
+        }
+
+        writer.writeEndElement();
+        break;
+
+      case GeographyCollection:
+      case GeometryCollection:
+        writer.writeStartElement(Constants.PREFIX_GML, Constants.ELEM_GEOCOLLECTION, Constants.NS_GML);
+        writeSrsName(writer, value);
+
+        if (!((GeospatialCollection) value).isEmpty()) {
+          writer.writeStartElement(Constants.PREFIX_GML, Constants.ELEM_GEOMEMBERS, Constants.NS_GML);
+          for (final Iterator<Geospatial> itor = ((GeospatialCollection) value).iterator(); itor.hasNext();) {
+            serialize(writer, itor.next());
+          }
+          writer.writeEndElement();
+        }
+
+        writer.writeEndElement();
+        break;
+
+      default:
+    }
+  }
+
+}

http://git-wip-us.apache.org/repos/asf/olingo-odata4/blob/b15439ff/lib/commons-core/src/main/java/org/apache/olingo/commons/core/serialization/AtomSerializer.java
----------------------------------------------------------------------
diff --git a/lib/commons-core/src/main/java/org/apache/olingo/commons/core/serialization/AtomSerializer.java b/lib/commons-core/src/main/java/org/apache/olingo/commons/core/serialization/AtomSerializer.java
new file mode 100644
index 0000000..fb2a041
--- /dev/null
+++ b/lib/commons-core/src/main/java/org/apache/olingo/commons/core/serialization/AtomSerializer.java
@@ -0,0 +1,544 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.apache.olingo.commons.core.serialization;
+
+import java.io.Writer;
+import java.util.Collections;
+import java.util.List;
+
+import javax.xml.XMLConstants;
+import javax.xml.stream.XMLOutputFactory;
+import javax.xml.stream.XMLStreamException;
+import javax.xml.stream.XMLStreamWriter;
+
+import org.apache.commons.lang3.StringUtils;
+import org.apache.olingo.commons.api.Constants;
+import org.apache.olingo.commons.api.data.Annotation;
+import org.apache.olingo.commons.api.data.CollectionValue;
+import org.apache.olingo.commons.api.data.Entity;
+import org.apache.olingo.commons.api.data.EntitySet;
+import org.apache.olingo.commons.api.data.Link;
+import org.apache.olingo.commons.api.data.Property;
+import org.apache.olingo.commons.api.data.ResWrap;
+import org.apache.olingo.commons.api.data.Value;
+import org.apache.olingo.commons.api.domain.ODataOperation;
+import org.apache.olingo.commons.api.edm.EdmPrimitiveTypeKind;
+import org.apache.olingo.commons.api.edm.constants.ODataServiceVersion;
+import org.apache.olingo.commons.api.format.ContentType;
+import org.apache.olingo.commons.api.serialization.ODataSerializer;
+import org.apache.olingo.commons.api.serialization.ODataSerializerException;
+import org.apache.olingo.commons.core.data.AbstractODataObject;
+import org.apache.olingo.commons.core.data.EntityImpl;
+import org.apache.olingo.commons.core.data.EntitySetImpl;
+import org.apache.olingo.commons.core.data.LinkImpl;
+import org.apache.olingo.commons.core.edm.EdmTypeInfo;
+
+import com.fasterxml.aalto.stax.OutputFactoryImpl;
+
+public class AtomSerializer extends AbstractAtomDealer implements ODataSerializer {
+
+  private static final XMLOutputFactory FACTORY = new OutputFactoryImpl();
+
+  private final AtomGeoValueSerializer geoSerializer;
+
+  private final boolean serverMode;
+
+  public AtomSerializer(final ODataServiceVersion version) {
+    this(version, false);
+  }
+
+  public AtomSerializer(final ODataServiceVersion version, final boolean serverMode) {
+    super(version);
+    this.geoSerializer = new AtomGeoValueSerializer();
+    this.serverMode = serverMode;
+  }
+
+  private void collection(final XMLStreamWriter writer, final CollectionValue value) throws XMLStreamException {
+    for (Value item : value.get()) {
+      if (version.compareTo(ODataServiceVersion.V40) < 0) {
+        writer.writeStartElement(Constants.PREFIX_DATASERVICES, Constants.ELEM_ELEMENT,
+            version.getNamespaceMap().get(ODataServiceVersion.NS_DATASERVICES));
+      } else {
+        writer.writeStartElement(Constants.PREFIX_METADATA, Constants.ELEM_ELEMENT,
+            version.getNamespaceMap().get(ODataServiceVersion.NS_METADATA));
+      }
+      value(writer, item);
+      writer.writeEndElement();
+    }
+  }
+
+  private void value(final XMLStreamWriter writer, final Value value) throws XMLStreamException {
+    if (value.isPrimitive()) {
+      writer.writeCharacters(value.asPrimitive().get());
+    } else if (value.isEnum()) {
+      writer.writeCharacters(value.asEnum().get());
+    } else if (value.isGeospatial()) {
+      this.geoSerializer.serialize(writer, value.asGeospatial().get());
+    } else if (value.isCollection()) {
+      collection(writer, value.asCollection());
+    } else if (value.isComplex()) {
+      for (Property property : value.asComplex().get()) {
+        property(writer, property, false);
+      }
+    }
+  }
+
+  public void property(final XMLStreamWriter writer, final Property property, final boolean standalone)
+      throws XMLStreamException {
+
+    if (version.compareTo(ODataServiceVersion.V40) >= 0 && standalone) {
+      writer.writeStartElement(Constants.PREFIX_METADATA, Constants.VALUE,
+          version.getNamespaceMap().get(ODataServiceVersion.NS_DATASERVICES));
+    } else {
+      writer.writeStartElement(Constants.PREFIX_DATASERVICES, property.getName(),
+          version.getNamespaceMap().get(ODataServiceVersion.NS_DATASERVICES));
+    }
+
+    if (standalone) {
+      namespaces(writer);
+    }
+
+    if (StringUtils.isNotBlank(property.getType())) {
+      final EdmTypeInfo typeInfo = new EdmTypeInfo.Builder().setTypeExpression(property.getType()).build();
+      if (!EdmPrimitiveTypeKind.String.getFullQualifiedName().toString().equals(typeInfo.internal())) {
+        writer.writeAttribute(Constants.PREFIX_METADATA, version.getNamespaceMap().get(ODataServiceVersion.NS_METADATA),
+            Constants.ATTR_TYPE, typeInfo.external(version));
+      }
+    }
+
+    if (property.getValue().isNull()) {
+      writer.writeAttribute(Constants.PREFIX_METADATA, version.getNamespaceMap().get(ODataServiceVersion.NS_METADATA),
+          Constants.ATTR_NULL, Boolean.TRUE.toString());
+    } else {
+      value(writer, property.getValue());
+      if (property.getValue().isLinkedComplex()) {
+        links(writer, property.getValue().asLinkedComplex().getAssociationLinks());
+        links(writer, property.getValue().asLinkedComplex().getNavigationLinks());
+      }
+    }
+
+    writer.writeEndElement();
+
+    for (Annotation annotation : property.getAnnotations()) {
+      annotation(writer, annotation, property.getName());
+    }
+  }
+
+  private void property(final XMLStreamWriter writer, final Property property) throws XMLStreamException {
+    property(writer, property, true);
+  }
+
+  private void startDocument(final XMLStreamWriter writer, final String rootElement) throws XMLStreamException {
+    writer.writeStartDocument();
+    writer.setDefaultNamespace(Constants.NS_ATOM);
+
+    writer.writeStartElement(rootElement);
+
+    namespaces(writer);
+  }
+
+  private void property(final Writer outWriter, final Property property) throws XMLStreamException {
+    final XMLStreamWriter writer = FACTORY.createXMLStreamWriter(outWriter);
+
+    writer.writeStartDocument();
+
+    property(writer, property);
+
+    writer.writeEndDocument();
+    writer.flush();
+  }
+
+  private void links(final XMLStreamWriter writer, final List<Link> links) throws XMLStreamException {
+    for (Link link : links) {
+      writer.writeStartElement(Constants.ATOM_ELEM_LINK);
+
+      if (StringUtils.isNotBlank(link.getRel())) {
+        writer.writeAttribute(Constants.ATTR_REL, link.getRel());
+      }
+      if (StringUtils.isNotBlank(link.getTitle())) {
+        writer.writeAttribute(Constants.ATTR_TITLE, link.getTitle());
+      }
+      if (StringUtils.isNotBlank(link.getHref())) {
+        writer.writeAttribute(Constants.ATTR_HREF, link.getHref());
+      }
+      if (StringUtils.isNotBlank(link.getType())) {
+        writer.writeAttribute(Constants.ATTR_TYPE, link.getType());
+      }
+
+      if (link.getInlineEntity() != null || link.getInlineEntitySet() != null) {
+        writer.writeStartElement(Constants.PREFIX_METADATA, Constants.ATOM_ELEM_INLINE,
+            version.getNamespaceMap().get(ODataServiceVersion.NS_METADATA));
+
+        if (link.getInlineEntity() != null) {
+          writer.writeStartElement(Constants.ATOM_ELEM_ENTRY);
+          entity(writer, link.getInlineEntity());
+          writer.writeEndElement();
+        }
+        if (link.getInlineEntitySet() != null) {
+          writer.writeStartElement(Constants.ATOM_ELEM_FEED);
+          entitySet(writer, link.getInlineEntitySet());
+          writer.writeEndElement();
+        }
+
+        writer.writeEndElement();
+      }
+
+      for (Annotation annotation : link.getAnnotations()) {
+        annotation(writer, annotation, null);
+      }
+
+      writer.writeEndElement();
+    }
+  }
+
+  private void common(final XMLStreamWriter writer, final AbstractODataObject object) throws XMLStreamException {
+    if (StringUtils.isNotBlank(object.getTitle())) {
+      writer.writeStartElement(Constants.ATOM_ELEM_TITLE);
+      writer.writeAttribute(Constants.ATTR_TYPE, TYPE_TEXT);
+      writer.writeCharacters(object.getTitle());
+      writer.writeEndElement();
+    }
+  }
+
+  private void properties(final XMLStreamWriter writer, final List<Property> properties) throws XMLStreamException {
+    for (Property property : properties) {
+      property(writer, property, false);
+    }
+  }
+
+  private void annotation(final XMLStreamWriter writer, final Annotation annotation, final String target)
+      throws XMLStreamException {
+
+    writer.writeStartElement(Constants.PREFIX_METADATA, Constants.ANNOTATION,
+        version.getNamespaceMap().get(ODataServiceVersion.NS_METADATA));
+
+    writer.writeAttribute(Constants.ATOM_ATTR_TERM, annotation.getTerm());
+
+    if (target != null) {
+      writer.writeAttribute(Constants.ATTR_TARGET, target);
+    }
+
+    if (StringUtils.isNotBlank(annotation.getType())) {
+      final EdmTypeInfo typeInfo = new EdmTypeInfo.Builder().setTypeExpression(annotation.getType()).build();
+      if (!EdmPrimitiveTypeKind.String.getFullQualifiedName().toString().equals(typeInfo.internal())) {
+        writer.writeAttribute(Constants.PREFIX_METADATA, version.getNamespaceMap().get(ODataServiceVersion.NS_METADATA),
+            Constants.ATTR_TYPE, typeInfo.external(version));
+      }
+    }
+
+    if (annotation.getValue().isNull()) {
+      writer.writeAttribute(Constants.PREFIX_METADATA, version.getNamespaceMap().get(ODataServiceVersion.NS_METADATA),
+          Constants.ATTR_NULL, Boolean.TRUE.toString());
+    } else {
+      value(writer, annotation.getValue());
+    }
+
+    writer.writeEndElement();
+  }
+
+  private void entity(final XMLStreamWriter writer, final Entity entity) throws XMLStreamException {
+    if (entity.getBaseURI() != null) {
+      writer.writeAttribute(XMLConstants.XML_NS_URI, Constants.ATTR_XML_BASE, entity.getBaseURI().toASCIIString());
+    }
+
+    if (serverMode && StringUtils.isNotBlank(entity.getETag())) {
+      writer.writeAttribute(
+          version.getNamespaceMap().get(ODataServiceVersion.NS_METADATA),
+          Constants.ATOM_ATTR_ETAG, entity.getETag());
+    }
+
+    if (entity.getId() != null) {
+      writer.writeStartElement(Constants.ATOM_ELEM_ID);
+      writer.writeCharacters(entity.getId().toASCIIString());
+      writer.writeEndElement();
+    }
+
+    writer.writeStartElement(Constants.ATOM_ELEM_CATEGORY);
+    writer.writeAttribute(Constants.ATOM_ATTR_SCHEME, version.getNamespaceMap().get(ODataServiceVersion.NS_SCHEME));
+    if (StringUtils.isNotBlank(entity.getType())) {
+      writer.writeAttribute(Constants.ATOM_ATTR_TERM,
+          new EdmTypeInfo.Builder().setTypeExpression(entity.getType()).build().external(version));
+    }
+    writer.writeEndElement();
+
+    if (entity instanceof AbstractODataObject) {
+      common(writer, (AbstractODataObject) entity);
+    }
+
+    if (serverMode) {
+      if (entity.getEditLink() != null) {
+        links(writer, Collections.singletonList(entity.getEditLink()));
+      }
+
+      if (entity.getSelfLink() != null) {
+        links(writer, Collections.singletonList(entity.getSelfLink()));
+      }
+    }
+
+    links(writer, entity.getAssociationLinks());
+    links(writer, entity.getNavigationLinks());
+    links(writer, entity.getMediaEditLinks());
+
+    if (serverMode) {
+      for (ODataOperation operation : entity.getOperations()) {
+        writer.writeStartElement(
+            version.getNamespaceMap().get(ODataServiceVersion.NS_METADATA), Constants.ATOM_ELEM_ACTION);
+        writer.writeAttribute(Constants.ATTR_METADATA, operation.getMetadataAnchor());
+        writer.writeAttribute(Constants.ATTR_TITLE, operation.getTitle());
+        writer.writeAttribute(Constants.ATTR_TARGET, operation.getTarget().toASCIIString());
+        writer.writeEndElement();
+      }
+    }
+
+    writer.writeStartElement(Constants.ATOM_ELEM_CONTENT);
+    if (entity.isMediaEntity()) {
+      if (StringUtils.isNotBlank(entity.getMediaContentType())) {
+        writer.writeAttribute(Constants.ATTR_TYPE, entity.getMediaContentType());
+      }
+      if (entity.getMediaContentSource() != null) {
+        writer.writeAttribute(Constants.ATOM_ATTR_SRC, entity.getMediaContentSource().toASCIIString());
+      }
+      writer.writeEndElement();
+
+      writer.writeStartElement(version.getNamespaceMap().get(ODataServiceVersion.NS_METADATA), Constants.PROPERTIES);
+      properties(writer, entity.getProperties());
+    } else {
+      writer.writeAttribute(Constants.ATTR_TYPE, ContentType.APPLICATION_XML);
+      writer.writeStartElement(version.getNamespaceMap().get(ODataServiceVersion.NS_METADATA), Constants.PROPERTIES);
+      properties(writer, entity.getProperties());
+      writer.writeEndElement();
+    }
+    writer.writeEndElement();
+
+    for (Annotation annotation : entity.getAnnotations()) {
+      annotation(writer, annotation, null);
+    }
+  }
+
+  private void entityRef(final XMLStreamWriter writer, final Entity entity) throws XMLStreamException {
+    writer.writeStartElement(Constants.ATOM_ELEM_ENTRY_REF);
+    writer.writeNamespace(StringUtils.EMPTY, version.getNamespaceMap().get(ODataServiceVersion.NS_METADATA));
+    writer.writeAttribute(Constants.ATOM_ATTR_ID, entity.getId().toASCIIString());
+  }
+
+  private void entityRef(final XMLStreamWriter writer, final ResWrap<Entity> container) throws XMLStreamException {
+    writer.writeStartElement(Constants.ATOM_ELEM_ENTRY_REF);
+    writer.writeNamespace(StringUtils.EMPTY, version.getNamespaceMap().get(ODataServiceVersion.NS_METADATA));
+    addContextInfo(writer, container);
+    writer.writeAttribute(Constants.ATOM_ATTR_ID, container.getPayload().getId().toASCIIString());
+  }
+
+  private void entity(final Writer outWriter, final Entity entity) throws XMLStreamException {
+    final XMLStreamWriter writer = FACTORY.createXMLStreamWriter(outWriter);
+
+    if (entity.getType() == null && entity.getProperties().isEmpty()) {
+      writer.writeStartDocument();
+      writer.setDefaultNamespace(version.getNamespaceMap().get(ODataServiceVersion.NS_METADATA));
+
+      entityRef(writer, entity);
+    } else {
+      startDocument(writer, Constants.ATOM_ELEM_ENTRY);
+
+      entity(writer, entity);
+    }
+
+    writer.writeEndElement();
+    writer.writeEndDocument();
+    writer.flush();
+  }
+
+  private void entity(final Writer outWriter, final ResWrap<Entity> container) throws XMLStreamException {
+    final Entity entity = container.getPayload();
+
+    final XMLStreamWriter writer = FACTORY.createXMLStreamWriter(outWriter);
+
+    if (entity.getType() == null && entity.getProperties().isEmpty()) {
+      writer.writeStartDocument();
+      writer.setDefaultNamespace(version.getNamespaceMap().get(ODataServiceVersion.NS_METADATA));
+
+      entityRef(writer, container);
+    } else {
+      startDocument(writer, Constants.ATOM_ELEM_ENTRY);
+
+      addContextInfo(writer, container);
+
+      entity(writer, entity);
+    }
+
+    writer.writeEndElement();
+    writer.writeEndDocument();
+    writer.flush();
+  }
+
+  private void entitySet(final XMLStreamWriter writer, final EntitySet entitySet) throws XMLStreamException {
+    if (entitySet.getBaseURI() != null) {
+      writer.writeAttribute(XMLConstants.XML_NS_URI, Constants.ATTR_XML_BASE, entitySet.getBaseURI().toASCIIString());
+    }
+
+    if (entitySet.getCount() != null) {
+      writer.writeStartElement(
+          version.getNamespaceMap().get(ODataServiceVersion.NS_METADATA), Constants.ATOM_ELEM_COUNT);
+      writer.writeCharacters(Integer.toString(entitySet.getCount()));
+      writer.writeEndElement();
+    }
+
+    if (entitySet.getId() != null) {
+      writer.writeStartElement(Constants.ATOM_ELEM_ID);
+      writer.writeCharacters(entitySet.getId().toASCIIString());
+      writer.writeEndElement();
+    }
+
+    if (entitySet instanceof AbstractODataObject) {
+      common(writer, (AbstractODataObject) entitySet);
+    }
+
+    for (Entity entity : entitySet.getEntities()) {
+      if (entity.getType() == null && entity.getProperties().isEmpty()) {
+        entityRef(writer, entity);
+        writer.writeEndElement();
+      } else {
+        writer.writeStartElement(Constants.ATOM_ELEM_ENTRY);
+        entity(writer, entity);
+        writer.writeEndElement();
+      }
+    }
+
+    if (serverMode) {
+      if (entitySet.getNext() != null) {
+        final LinkImpl next = new LinkImpl();
+        next.setRel(Constants.NEXT_LINK_REL);
+        next.setHref(entitySet.getNext().toASCIIString());
+
+        links(writer, Collections.<Link> singletonList(next));
+      }
+      if (entitySet.getDeltaLink() != null) {
+        final LinkImpl next = new LinkImpl();
+        next.setRel(Constants.DELTA_LINK_REL);
+        next.setHref(entitySet.getDeltaLink().toASCIIString());
+
+        links(writer, Collections.<Link> singletonList(next));
+      }
+    }
+  }
+
+  private void entitySet(final Writer outWriter, final EntitySet entitySet) throws XMLStreamException {
+    final XMLStreamWriter writer = FACTORY.createXMLStreamWriter(outWriter);
+
+    startDocument(writer, Constants.ATOM_ELEM_FEED);
+
+    entitySet(writer, entitySet);
+
+    writer.writeEndElement();
+    writer.writeEndDocument();
+    writer.flush();
+  }
+
+  private void entitySet(final Writer outWriter, final ResWrap<EntitySet> entitySet) throws XMLStreamException {
+    final XMLStreamWriter writer = FACTORY.createXMLStreamWriter(outWriter);
+
+    startDocument(writer, Constants.ATOM_ELEM_FEED);
+
+    addContextInfo(writer, entitySet);
+
+    entitySet(writer, entitySet.getPayload());
+
+    writer.writeEndElement();
+    writer.writeEndDocument();
+    writer.flush();
+  }
+
+  private void link(final Writer outWriter, final Link link) throws XMLStreamException {
+    final XMLStreamWriter writer = FACTORY.createXMLStreamWriter(outWriter);
+
+    writer.writeStartDocument();
+
+    writer.writeStartElement(Constants.ELEM_LINKS);
+    writer.writeDefaultNamespace(version.getNamespaceMap().get(ODataServiceVersion.NS_DATASERVICES));
+
+    writer.writeStartElement(Constants.ELEM_URI);
+    writer.writeCharacters(link.getHref());
+    writer.writeEndElement();
+
+    writer.writeEndElement();
+
+    writer.writeEndDocument();
+    writer.flush();
+  }
+
+  public <T> void write(final Writer writer, final T obj) throws ODataSerializerException {
+    try {
+      if (obj instanceof EntitySet) {
+        entitySet(writer, (EntitySet) obj);
+      } else if (obj instanceof Entity) {
+        entity(writer, (Entity) obj);
+      } else if (obj instanceof Property) {
+        property(writer, (Property) obj);
+      } else if (obj instanceof Link) {
+        link(writer, (Link) obj);
+      }
+    } catch (final XMLStreamException e) {
+      throw new ODataSerializerException(e);
+    }
+  }
+
+  @SuppressWarnings("unchecked")
+  public <T> void write(final Writer writer, final ResWrap<T> container) throws ODataSerializerException {
+    final T obj = container == null ? null : container.getPayload();
+
+    try {
+      if (obj instanceof EntitySet) {
+        this.entitySet(writer, (ResWrap<EntitySet>) container);
+      } else if (obj instanceof Entity) {
+        entity(writer, (ResWrap<Entity>) container);
+      } else if (obj instanceof Property) {
+        property(writer, (Property) obj);
+      } else if (obj instanceof Link) {
+        link(writer, (Link) obj);
+      }
+    } catch (final XMLStreamException e) {
+      throw new ODataSerializerException(e);
+    }
+  }
+
+  private <T> void addContextInfo(
+      final XMLStreamWriter writer, final ResWrap<T> container) throws XMLStreamException {
+
+    if (container.getContextURL() != null) {
+      String base = container.getContextURL().getServiceRoot().toASCIIString();
+      if (container.getPayload() instanceof EntitySet) {
+        ((EntitySetImpl) container.getPayload()).setBaseURI(base);
+      }
+      if (container.getPayload() instanceof Entity) {
+        ((EntityImpl) container.getPayload()).setBaseURI(base);
+      }
+
+      writer.writeAttribute(
+          version.getNamespaceMap().get(ODataServiceVersion.NS_METADATA),
+          Constants.CONTEXT,
+          container.getContextURL().getURI().toASCIIString());
+    }
+
+    if (StringUtils.isNotBlank(container.getMetadataETag())) {
+      writer.writeAttribute(
+          version.getNamespaceMap().get(ODataServiceVersion.NS_METADATA),
+          Constants.ATOM_ATTR_METADATAETAG,
+          container.getMetadataETag());
+    }
+  }
+}

http://git-wip-us.apache.org/repos/asf/olingo-odata4/blob/b15439ff/lib/commons-core/src/main/java/org/apache/olingo/commons/core/serialization/JsonDeltaDeserializer.java
----------------------------------------------------------------------
diff --git a/lib/commons-core/src/main/java/org/apache/olingo/commons/core/serialization/JsonDeltaDeserializer.java b/lib/commons-core/src/main/java/org/apache/olingo/commons/core/serialization/JsonDeltaDeserializer.java
new file mode 100644
index 0000000..c6df8f3
--- /dev/null
+++ b/lib/commons-core/src/main/java/org/apache/olingo/commons/core/serialization/JsonDeltaDeserializer.java
@@ -0,0 +1,102 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.apache.olingo.commons.core.serialization;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URI;
+import java.util.Iterator;
+
+import org.apache.commons.lang3.StringUtils;
+import org.apache.olingo.commons.api.Constants;
+import org.apache.olingo.commons.api.data.ContextURL;
+import org.apache.olingo.commons.api.data.Delta;
+import org.apache.olingo.commons.api.data.ResWrap;
+import org.apache.olingo.commons.api.edm.constants.ODataServiceVersion;
+import org.apache.olingo.commons.api.serialization.ODataDeserializerException;
+import org.apache.olingo.commons.core.data.DeletedEntityImpl;
+import org.apache.olingo.commons.core.data.DeltaLinkImpl;
+import org.apache.olingo.commons.core.data.v4.DeltaImpl;
+
+import com.fasterxml.jackson.core.JsonFactory;
+import com.fasterxml.jackson.core.JsonParser;
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+
+public class JsonDeltaDeserializer extends JsonDeserializer {
+
+  public JsonDeltaDeserializer(final ODataServiceVersion version, final boolean serverMode) {
+    super(version, serverMode);
+  }
+
+  protected ResWrap<Delta> doDeserialize(final JsonParser parser) throws IOException {
+
+    final ObjectNode tree = parser.getCodec().readTree(parser);
+
+    final DeltaImpl delta = new DeltaImpl();
+
+    final URI contextURL = tree.hasNonNull(Constants.JSON_CONTEXT) ?
+        URI.create(tree.get(Constants.JSON_CONTEXT).textValue()) : null;
+    if (contextURL != null) {
+      delta.setBaseURI(StringUtils.substringBefore(contextURL.toASCIIString(), Constants.METADATA));
+    }
+
+    if (tree.hasNonNull(jsonCount)) {
+      delta.setCount(tree.get(jsonCount).asInt());
+    }
+    if (tree.hasNonNull(jsonNextLink)) {
+      delta.setNext(URI.create(tree.get(jsonNextLink).textValue()));
+    }
+    if (tree.hasNonNull(jsonDeltaLink)) {
+      delta.setDeltaLink(URI.create(tree.get(jsonDeltaLink).textValue()));
+    }
+
+    if (tree.hasNonNull(Constants.VALUE)) {
+      JsonEntityDeserializer entityDeserializer = new JsonEntityDeserializer(version, serverMode);
+      for (final Iterator<JsonNode> itor = tree.get(Constants.VALUE).iterator(); itor.hasNext();) {
+        final ObjectNode item = (ObjectNode) itor.next();
+        final ContextURL itemContextURL = item.hasNonNull(Constants.JSON_CONTEXT)
+            ? ContextURL.getInstance(URI.create(item.get(Constants.JSON_CONTEXT).textValue())) : null;
+        item.remove(Constants.JSON_CONTEXT);
+
+        if (itemContextURL == null || itemContextURL.isEntity()) {
+          delta.getEntities().add(entityDeserializer.doDeserialize(item.traverse(parser.getCodec())).getPayload());
+        } else if (itemContextURL.isDeltaDeletedEntity()) {
+          delta.getDeletedEntities().add(parser.getCodec().treeToValue(item, DeletedEntityImpl.class));
+        } else if (itemContextURL.isDeltaLink()) {
+          delta.getAddedLinks().add(parser.getCodec().treeToValue(item, DeltaLinkImpl.class));
+        } else if (itemContextURL.isDeltaDeletedLink()) {
+          delta.getDeletedLinks().add(parser.getCodec().treeToValue(item, DeltaLinkImpl.class));
+        }
+      }
+    }
+
+    return new ResWrap<Delta>(contextURL, null, delta);
+  }
+
+  public ResWrap<Delta> toDelta(InputStream input) throws ODataDeserializerException {
+    try {
+      JsonParser parser = new JsonFactory(new ObjectMapper()).createParser(input);
+      return doDeserialize(parser);
+    } catch (final IOException e) {
+      throw new ODataDeserializerException(e);
+    }
+  }
+}