core/src/main/java/flex/messaging/io/PageableRowSetProxy.java

/*
 * 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 flex.messaging.io;

import flex.messaging.MessageException;

import javax.sql.RowSet;
import java.sql.SQLException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * A wrapped PageableRowSet instance requires custom serialization so this
 * legacy type has been made to fit the PropertyProxy interface. 
 * 
 * TODO: This proxy is similar to features made possible with Externalizable 
 * so PageableRowSet/RecordSet should be moved to an Externalizable 
 * implementation.
 */
public class PageableRowSetProxy extends AbstractProxy
{
    static final long serialVersionUID = 1121859941216924326L;

    public static final int HUGE_PAGE_SIZE = Integer.MAX_VALUE;

    /**
     * AS Object Type Name.
     */
    public static final String AS_TYPE_NAME = "RecordSet";

    public static final Integer RECORD_SET_VERSION = new Integer(1);
    
    /**
     * ActionScript (AS) Object Key Names.
     */
    public static final String TOTAL_COUNT = "totalCount";
    public static final String COLUMN_NAMES = "columnNames";
    public static final String INITIAL_DATA = "initialData";
    public static final String SERVICE_NAME = "serviceName";
    public static final String SERVER_INFO = "serverInfo";
    public static final String VERSION = "version";
    public static final String CURSOR = "cursor";
    public static final String ID = "id";

    public static final List propertyNameCache = new ArrayList();
    static
    {
        propertyNameCache.add(SERVER_INFO);
    }

    public PageableRowSetProxy()
    {
        super(null);
        alias = AS_TYPE_NAME;
    }
    
    public PageableRowSetProxy(RowSet defaultInstance)
    {
        super(defaultInstance);
        alias = AS_TYPE_NAME;
    }

    public PageableRowSetProxy(PageableRowSet defaultInstance)
    {
        super(defaultInstance);
        alias = AS_TYPE_NAME;
    }

    public String getAlias(Object instance)
    {
        return AS_TYPE_NAME;
    }
    
    public List getPropertyNames(Object instance)
    {
        return propertyNameCache;
    }

    public Class getType(Object instance, String propertyName)
    {
        if (SERVER_INFO.equals(propertyName))
        {
            return HashMap.class;
        }
        else
        {
            return null;
        }
    }

    public Object getValue(Object instance, String propertyName)
    {
        Object value = null;
        
        if (instance instanceof RowSet)
        {
            //Wrap in PageableRowSet just for its utility methods and don't create an id.
            instance = new PagedRowSet((RowSet)instance, HUGE_PAGE_SIZE, false);
        }

        if (instance instanceof PageableRowSet)
        {
            PageableRowSet prs = (PageableRowSet)instance;
            
            if (SERVER_INFO.equals(propertyName))
            {
                try
                {
                    HashMap serverInfo = new HashMap();
                    serverInfo.put(ID, prs.getID());
    
                    Map pageInfo = prs.getRecords(1, prs.getInitialDownloadCount());
        
                    serverInfo.put(TOTAL_COUNT, new Integer(prs.getRowCount()));
                    serverInfo.put(INITIAL_DATA, pageInfo.get(PageableRowSet.PAGE)); //Array of Arrays - the first page returned
                    serverInfo.put(CURSOR, pageInfo.get(PageableRowSet.CURSOR)); //Integer
                    serverInfo.put(SERVICE_NAME, prs.getServiceName());
                    serverInfo.put(COLUMN_NAMES, prs.getColumnNames());
                    serverInfo.put(VERSION, RECORD_SET_VERSION);
                    value = serverInfo;
                }
                catch (SQLException ex)
                {
                    MessageException e = new MessageException();
                    e.setMessage("Error encountered serializing RowSet.");
                    e.setRootCause(ex);
                    throw e;
                }
            }
        }

        return value;
    }

    public void setValue(Object instance, String propertyName, Object value)
    {
       // Client-to-server not supported
    }
}