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CloudGraph(tm) is a suite of Service Data Object (SDO) 2.1 services designed for relational and big-table style "cloud" databases, such as HBase and others.
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/**
 *        CloudGraph Community Edition (CE) License
 * 
 * This is a community release of CloudGraph, a dual-license suite of
 * Service Data Object (SDO) 2.1 services designed for relational and 
 * big-table style "cloud" databases, such as HBase and others. 
 * This particular copy of the software is released under the 
 * version 2 of the GNU General Public License. CloudGraph was developed by 
 * TerraMeta Software, Inc.
 * 
 * Copyright (c) 2013, TerraMeta Software, Inc. All rights reserved.
 * 
 * General License information can be found below.
 * 
 * This distribution may include materials developed by third
 * parties. For license and attribution notices for these
 * materials, please refer to the documentation that accompanies
 * this distribution (see the "Licenses for Third-Party Components"
 * appendix) or view the online documentation at 
 * . 
 */
package org.cloudgraph.hbase.io;

import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.UUID;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.cloudgraph.common.CloudGraphConstants;
import org.cloudgraph.hbase.key.CompositeRowKeyFactory;
import org.plasma.sdo.PlasmaDataGraph;
import org.plasma.sdo.PlasmaDataObject;
import org.plasma.sdo.PlasmaType;
import org.plasma.sdo.core.CoreDataObject;

import commonj.sdo.DataObject;

public abstract class WriterSupport {
    private static Log log = LogFactory.getLog(WriterSupport.class);
	protected Map rowWriterMap = new HashMap();	
	
	protected WriterSupport() {
		
	}
	
	/**
	 * Finds and return the row writer associated with the container
	 * for the given target data object
	 * @param target the target data object
	 * @return the row writer associated with the container
	 * for the given target data object
	 * @throws OperationException if no row writer found
	 */
	protected RowWriter getContainerRowWriter(DataObject target) {		
		RowWriter result = findContainerRowWriter(target);
		if (result == null)
		    throw new OperationException("no row writer associated with data object, " 
	    	    + String.valueOf(target) + ", or its containment ancestry");
		return result;
	}
	
	/**
	 * Finds and return the row writer associated with the 
	 * given target data object
	 * @param target the target data object
	 * @return the row writer associated with the 
	 * given target data object, or null if no writer found
	 */
	protected RowWriter findContainerRowWriter(DataObject target) {		
		RowWriter result = null;
		DataObject container = target.getContainer();
		while (container != null) {
			if (log.isDebugEnabled()) 
				log.debug("checking " + container + " container for " + target);
			result = this.rowWriterMap.get(container);
			if (result != null)
				return result;
			container = container.getContainer();
		}
		return null;
	}
	
	/**
	 * Traverses the container links for the given data object
	 * returning the ancestry as an ordered list. 
	 * @param target
	 * @return
	 */
	protected List getContainerAncestry(DataObject target) {		
		List result = new ArrayList();
		DataObject source = target.getContainer();
		while (source != null) {
			result.add(source);
			source = source.getContainer();
		}
		return result;
	}	

	
	/**
	 * Creates and returns a new row writer for the given (row root) data object.
	 * If an existing row key is set into the 
	 * instance property collection for the (row root) data object, the existing
	 * row key is used, otherwise a row key is generated. For objects
	 * flagged as deleted in the SDO change summary, re-generating a row key
	 * may not be possible, as for deleted operations
	 * SDO requires the removal of all properties (other than 
	 * read-only) for all deleted data objects. If such removed 
	 * properties are required for a row key, this makes re-generation 
	 * for the row key impossible, and the key generator will throw an error.     
	 * @param tableWriter the table writer
	 * @param target the target (row root) data object
	 * @return the new row writer
	 * @throws IOException
	 */
	protected RowWriter createRowWriter(TableWriter tableWriter, DataObject target) throws IOException
	{
    	CoreDataObject coreObject = (CoreDataObject)target;
		byte[] rowKey = (byte[])coreObject.getValueObject().get(
        		CloudGraphConstants.ROW_KEY);
        if (rowKey == null) {
	        CompositeRowKeyFactory rowKeyGen = new CompositeRowKeyFactory(
		        	(PlasmaType)target.getType());		        
		    rowKey = rowKeyGen.createRowKeyBytes(target); 
            coreObject.getValueObject().put(
	        		CloudGraphConstants.ROW_KEY, rowKey);
			if (target.getDataGraph().getRootObject().equals(target)) // graph root object
                ((PlasmaDataGraph)target.getDataGraph()).setId(rowKey); // FIXME: snapshot map for this? 
        }
		RowWriter rowWriter = this.createRowWriter(tableWriter,
        		target, rowKey);
		
		return rowWriter;
	}
	
	/**
	 * Creates and returns a new row writer for the given (row root) data object.
	 * @param tableContext the table context
	 * @param dataObject the (row root) data object
	 * @param rowKey the existing row key
	 * @return the new row writer
	 * @throws IOException
	 */
	protected RowWriter createRowWriter(TableWriter tableContext,
			DataObject dataObject,
	    	byte[] rowKey) throws IOException
    {   	
    	RowWriter rowContext = 
    		new GraphRowWriter(rowKey, dataObject, tableContext);

    	UUID uuid = ((PlasmaDataObject)dataObject).getUUID();
    	tableContext.addRowWriter(uuid, rowContext);
    	
    	return rowContext;
    }

	/**
	 * Creates adds and returns a new row writer for the given (row root) 
	 * data object. If an existing row key is set into the 
	 * instance property collection for the (row root) data object, the existing
	 * row key is used, otherwise a row key is generated. For objects
	 * flagged as deleted in the SDO change summary, re-generating a row key
	 * may not be possible, as for deleted operations
	 * SDO requires the removal of all properties (other than 
	 * read-only) for all deleted data objects. If such removed 
	 * properties are required for a row key, this makes re-generation 
	 * for the row key impossible, and the key generator will throw an error.    
	 * @param dataObject the target (row root) data object
	 * @param tableContext the table context
	 * @return the new row writer
	 * @throws IOException
	 */
	protected RowWriter addRowWriter( 
    		DataObject dataObject,
    		TableWriter tableContext) throws IOException
    {
		byte[] rowKey = null;
    	CoreDataObject coreObject = (CoreDataObject)dataObject;
    	rowKey = (byte[])coreObject.getValueObject().get(
        		CloudGraphConstants.ROW_KEY);
        if (rowKey == null) {
            CompositeRowKeyFactory rowKeyGen = new CompositeRowKeyFactory(
    	        	(PlasmaType)dataObject.getType());        
            rowKey = rowKeyGen.createRowKeyBytes(dataObject);
            coreObject.getValueObject().put(
            		CloudGraphConstants.ROW_KEY, rowKey);
        }
        RowWriter rowContext = new GraphRowWriter(
    		rowKey, dataObject, tableContext);
    	UUID uuid = ((PlasmaDataObject)dataObject).getUUID();
    	tableContext.addRowWriter(uuid, rowContext);
    	return rowContext;
    }
}