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.
/**
 * 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.azure.storage;

import java.io.IOException;
import java.io.InputStream;
import java.text.ParseException;
import java.util.Stack;

import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;

import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

import com.microsoft.azure.storage.core.SR;
import com.microsoft.azure.storage.core.Utility;

RESERVED FOR INTERNAL USE. A class used to deserialize service stats.
/**
 * RESERVED FOR INTERNAL USE. A class used to deserialize service stats.
 */
final class ServiceStatsHandler extends DefaultHandler {
    
The name of the geo-replication XML element.
/**
     * The name of the geo-replication XML element.
     */
    private final static String GEO_REPLICATION_NAME = "GeoReplication";

    
The name of the status XML element.
/**
     * The name of the status XML element.
     */
    private final static String STATUS_NAME = "Status";

    
The name of the last sync time XML element.
/**
     * The name of the last sync time XML element.
     */
    private final static String LAST_SYNC_TIME_NAME = "LastSyncTime";

    private final Stack<String> elementStack = new Stack<String>();
    private StringBuilder bld = new StringBuilder();

    private final GeoReplicationStats geoReplicationStats = new GeoReplicationStats();
    private final ServiceStats stats = new ServiceStats();

    
Constructs a ServiceStats object from an XML document received from the service. 
Params:
inStream – 
           The XMLStreamReader object.
Throws:
SAXException – 
ParserConfigurationException – 
IOException – 
Returns:
 A ServiceStats object containing the properties in the XML document./**
     * Constructs a {@link ServiceStats} object from an XML document received from the service.
     * 
     * @param inStream
     *            The XMLStreamReader object.
     * @return

     *         A {@link ServiceStats} object containing the properties in the XML document.
     * 
     * @throws SAXException
     * @throws ParserConfigurationException
     * @throws IOException
     */
    public static ServiceStats readServiceStatsFromStream(final InputStream inStream)
            throws ParserConfigurationException, SAXException, IOException {
        SAXParser saxParser = Utility.getSAXParser();
        ServiceStatsHandler handler = new ServiceStatsHandler();
        saxParser.parse(inStream, handler);

        return handler.stats;
    }

    @Override
    public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
        this.elementStack.push(localName);
    }

    @Override
    public void endElement(String uri, String localName, String qName) throws SAXException {
        String currentNode = this.elementStack.pop();

        // if the node popped from the stack and the localName don't match, the xml document is improperly formatted
        if (!localName.equals(currentNode)) {
            throw new SAXException(SR.INVALID_RESPONSE_RECEIVED);
        }

        String value = this.bld.toString();
        if (value.isEmpty()) {
            value = null;
        }

        if (GEO_REPLICATION_NAME.equals(currentNode)) {
            this.stats.setGeoReplication(this.geoReplicationStats);
        }
        else if (STATUS_NAME.equals(currentNode)) {
            this.geoReplicationStats.setStatus(GeoReplicationStatus.parse(value));
        }
        else if (LAST_SYNC_TIME_NAME.equals(currentNode)) {
            try {
                this.geoReplicationStats.setLastSyncTime(Utility.isNullOrEmpty(value) ? null : Utility
                        .parseRFC1123DateFromStringInGMT(value));
            }
            catch (ParseException e) {
                throw new SAXException(e);
            }
        }

        this.bld = new StringBuilder();
    }

    @Override
    public void characters(char ch[], int start, int length) throws SAXException {
        this.bld.append(ch, start, length);
    }

}