/**
* Copyright Microsoft Corporation
*
* 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.microsoft.windowsazure.services.media.implementation;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import javax.xml.bind.JAXBElement;
import com.microsoft.windowsazure.services.media.implementation.atom.ContentType;
import com.microsoft.windowsazure.services.media.implementation.atom.EntryType;
import com.microsoft.windowsazure.services.media.implementation.atom.LinkType;
import com.microsoft.windowsazure.services.media.implementation.content.Constants;
import com.microsoft.windowsazure.services.media.models.LinkInfo;
import com.microsoft.windowsazure.services.media.models.ListResult;
/**
* Class wrapping deserialized OData entities. Allows easy access to entry and
* content types.
*
*/
public abstract class ODataEntity<T> {
private final EntryType entry;
private final T content;
protected ODataEntity(EntryType entry, T content) {
this.entry = entry;
this.content = content;
}
@SuppressWarnings({ "unchecked", "rawtypes" })
protected ODataEntity(T content) {
this.content = content;
ContentType contentElement = new ContentType();
contentElement.getContent().add(
new JAXBElement(Constants.ODATA_PROPERTIES_ELEMENT_NAME,
content.getClass(), content));
entry = new EntryType();
entry.getEntryChildren().add(
new JAXBElement(Constants.ATOM_CONTENT_ELEMENT_NAME,
ContentType.class, contentElement));
}
/**
* @return the entry
*/
protected EntryType getEntry() {
return entry;
}
/**
* @return the content
*/
protected T getContent() {
return content;
}
/**
* Test if the entity contains a link with the given rel attribute.
*
* @param rel
* Rel of link to check for
* @return True if link is found, false if not.
*/
public boolean hasLink(String rel) {
return getLink(rel) != null;
}
/**
* Get the link with the given rel attribute
*
* @param rel
* rel of link to retrieve
* @return The link if found, null if not.
*/
public <U extends ODataEntity<?>> LinkInfo<U> getLink(String rel) {
for (Object child : entry.getEntryChildren()) {
LinkType link = linkFromChild(child);
if (link != null && link.getRel().equals(rel)) {
return new LinkInfo<U>(link);
}
}
return null;
}
/**
* Get the link to navigate an OData relationship
*
* @param relationName
* name of the OData relationship
* @return the link if found, null if not.
*/
public <U extends ODataEntity<?>> LinkInfo<U> getRelationLink(
String relationName) {
return this.<U> getLink(Constants.ODATA_DATA_NS + "/related/"
+ relationName);
}
@SuppressWarnings("rawtypes")
private static LinkType linkFromChild(Object child) {
if (child instanceof JAXBElement) {
return linkFromElement((JAXBElement) child);
}
return null;
}
private static LinkType linkFromElement(
@SuppressWarnings("rawtypes") JAXBElement element) {
if (element.getDeclaredType() == LinkType.class) {
return (LinkType) element.getValue();
}
return null;
}
/**
* Is the given type inherited from ODataEntity
*
* @param type
* Type to check
* @return true if derived from ODataEntity
*/
public static boolean isODataEntityType(Class<?> type) {
return ODataEntity.class.isAssignableFrom(type);
}
/**
* Is the given type a collection of ODataEntity
*
* @param type
* Base type
* @param genericType
* Generic type
* @return true if it's List<OEntity> or derive from.
*/
public static boolean isODataEntityCollectionType(Class<?> type,
Type genericType) {
if (ListResult.class != type) {
return false;
}
ParameterizedType pt = (ParameterizedType) genericType;
if (pt.getActualTypeArguments().length != 1) {
return false;
}
Class<?> typeClass = getCollectedType(genericType);
return isODataEntityType(typeClass);
}
/**
* Reflection helper to pull out the type parameter for a List<T>, where T
* is a ODataEntity<?> derived type.
*
* @param genericType
* type object for collection
* @return The class object for the type parameter.
*/
public static Class<?> getCollectedType(Type genericType) {
ParameterizedType pt = (ParameterizedType) genericType;
if (pt.getActualTypeArguments().length != 1) {
throw new IllegalArgumentException("genericType");
}
return (Class<?>) pt.getActualTypeArguments()[0];
}
}