/**
* Copyright 2004 The Apache Software Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.lucene.gdata.server;
import java.util.Date;
import com.google.gdata.data.BaseEntry;
import com.google.gdata.data.BaseFeed;
/**
* The Service class represents an interface to access the GData service
* componentes of the GData-Server. It encapsulates all interactions with the
* GData client.
* <p>
* This class provides the base level common functionality required to access
* the GData components. It is also designed to act as a base class that can be
* extended for specific types of underlaying server components as different
* indexing or storage components.
* </p>
* <p>
* It could also encapsulate caching mechanismn build on top of the storage to
* reduce load on the storage component
* </p>
*
* @author Simon Willnauer
*
*
*/
public interface Service {
/**
* Service method to create an entry in an already created and existing
* feed. This method will create the entry and passes the entry to the
* indexing component to make the new entry accessable via <i>get-queries</i>.
* The response and the corresponding http status code will be added to the
* given <code>FeedResponse</code>.
*
* @param request -
* the current FeedRequest
* @param response -
* the current FeedResponse
* @return - the entry which has been created
* @throws ServiceException -
* if the corresponding feed does not exist or the storage can
* not be accessed
*/
public abstract BaseEntry createEntry(final GDataRequest request,
final GDataResponse response) throws ServiceException;
/**
* Service Method to delete an entry specified in the given FeedRequest.
* This method will remove the entry permanently. There will be no
* possiblity to restore the entry. The response and the corresponding http
* status code will be added to the given <code>FeedResponse</code>.
*
* @param request -
* the current FeedRequest
* @param response -
* the current FeedResponse
* @return - the entry wich has been deleted
* @throws ServiceException -
* if the entry does not exist or the storage can not be
* accessed
*/
public abstract BaseEntry deleteEntry(GDataRequest request, final GDataResponse response)
throws ServiceException;
/**
* Service method to update an existing entry in a existing feed context.
* The entry version will be checked and a <code>ServiceException</code>
* will be thrown if the version to update is outdated. The new entry will
* be passed to the indexing component to make the version accessable via
* <i>get-queries</i>.
*
* @param request -
* the current FeedRequest
* @param response -
* the current FeedResponse
* @return - the entry wich has been updated
* @throws ServiceException -
* if the corresponding feed does not exist, the storage can not
* be accessed or the version to update is out of date.
*/
public abstract BaseEntry updateEntry(final GDataRequest request,
final GDataResponse response) throws ServiceException;
/**
* Service method to retrieve a requested Feed. The feed will also be added to
* the given <code>FeedResponse</code> instance and can also be accessed
* via the <code>FeedResponse</code> object.
*
* @param request -
* the current FeedRequest
* @param response -
* the current FeedResponse
* @return - the requested feed
*
* @throws ServiceException -
* If the storage can not be accessed or the requested feed does
* not exist.
*/
public abstract BaseFeed getFeed(final GDataRequest request, final GDataResponse response)
throws ServiceException;
/**
* Service method to retrieve a requested entry. The entry will also be added to
* the given <code>FeedResponse</code> instance and can also be accessed
* via the <code>FeedResponse</code> object.
*
* @param request -
* the current FeedRequest
* @param response -
* the current FeedResponse
* @return - the requested entry
*
* @throws ServiceException -
* If the storage can not be accessed or the requested entry does
* not exist.
*/
public abstract BaseEntry getSingleEntry(final GDataRequest request, final GDataResponse response)
throws ServiceException;
/**
* will close the Service - service should not be used after this method has been called
*/
public void close();
/**
* Retruns the date of the last modification for the given feed id
* @param feedId - the id of the feed
* @return - the last modified date or the current date if the date can not be retrieved
* @throws ServiceException - if the storage can not be accessed
*/
public abstract Date getFeedLastModified(String feedId)throws ServiceException;
/**
* Retruns the date of the last modification for the given entry id
* @param entryId - the id of the entry
* @param feedId - the feed id this entry belongs to
* @return - the last modified date or the current date if the date can not be retrieved
* @throws ServiceException - if the storage can not be accessed
*/
public abstract Date getEntryLastModified(String entryId, String feedId)throws ServiceException;
}
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